Talk:Concrete/Archive 1

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Archive 1

Cracking

I changed the third sentence in the first paragraph of section 3.4 ("Cracking") from "Extending the period concrete stays damp during curing increases its strength." to "The strength of the concrete can be increased by keeping it damp for a longer period during the curing process."

I think it is easier to understand this way.

Truly confused. You say: it is both particular and *an individual*, hence occupying some space and time. But an individual as a noun refers to a person. I think you want to say that: it is both particular and individual, hence occupying some space and time. Then you expand on this and compound the confusion with: So, to say that something is concrete is to say that it is a particular *individual* that is located at a particular place and time. Are only individuals, i.e. people, concrete? I always thought my PC was concrete. I guess I had better look at it. An abstract PC will be little help in disputing this definition. Please clarify.

'Individuals' (as in P. F. Strawson's book by the title) in philosophical jargon refer not just to individual human beings but to any individual (numerically singular) thing.

A beautiful pun one of my profs made, completely unintentionally: Sometimes being concrete actually makes things harder. We need a place to put information about sidewalk-stuff, too.

:-) Hopefully, we'll be able to start disambiguating words with parentheses; then I'll direct you to concrete (metaphysics), I suppose.----

"In general, a [[concept]] is considered concrete if it is not abstract..."(from concrete)
"A concept is an abstract, universal mental entity that serves to designate a category or class of entities, events or relations."(from concept link)
I think I'm confused:)

The article mentions John Smeaton as the pioneer of the use of portland cement in concrete. John Smeaton's article, however, makes no mention of this, and both the [portland cement] and the [Joseph Aspdin] article cite Joseph Aspdin as its inventor. Can someone clarify/confirm? Uly 12:04, 12 May 2005 (UTC)

I need some help and advice on the production of cement and concrete in the 19th century. This relates to Oak Island (see entry in Wikipedia). I also have a website for collaborative study on this (some content has restricted access - pls just ask): http://oakisland.esolutionswork.com). Thanks - John Bartram

Poured concrete, esp. for naval architecture

Does anybody know how Poured Concrete Construction is done, especially for naval artictecutre? ---User:kstephent 14:06 (EST), 09 March 2006. (By the way, did you know Hermann Georing suggested a concrete locomotive?)

If you're talking about ferrocement boat hulls, isn't that usually gunnite/shotcrete sprayed onto rebar set in a plywood form that creates the outer, smooth shape of the hull? If so, the linked article has a section on that. Or are you asking a different question when you say "naval architecture?

Atlant 19:35, 9 March 2006 (UTC)

All concrete poured?

Surly all concrete is poured unless we place a distinction between those drier materials used for road bases or machine laid pavement quality concretes which have litle workability (or consistence as now termed in European standards). Perhaps the distinction shouldbe precast as opposed insitu?

One area of confusion that is bound to occur is the difference in terminology between America concrete industy and the European counterpart.

Actually, not all concrete is poured. Certain low-tech concrete products (such as the kind you set your mailbox post into) are set as powder in the hole or mixed with earth in the hole, then watered "in place". I'm not sure, but a similar process may sometimes be used to form rammed earth construction blocks.

Closer to reality ( :-) ), shotcrete really isn't poured.

Atlant 01:02, 21 March 2006 (UTC)

At least all concrete is placed by some sort of action.. Oyvind 07:55, 21 March 2006 (UTC)

Roman concrete was pretty stiff. it was done in layers. the workers placed fist sized stones in a layer, and then the concrete was tamped into place with bars. -- Dullfig 23:57, 23 March 2006 (UTC)

Hi, yes, when one comes to think of it not all concrete is poured. The strength of concrete is determined by the water cement ratio, the less water in the mix the higher the final cured strength. We also get rollcrete used in the construction of large dams. Some mixes are very dry when placed in moulds which are rammed hydraulicly to provide required compaction. Some is pumped too. Regards, Gregorydavid 07:14, 24 March 2006 (UTC)

Glasscrete ?

Does anyone have information on substituting recycled glass for the sand and/or aggregate? I've heard it can be substituted up to 50% and can change the appearance of the finished concrete noticeably. Make it decorative and mottled, or more reflective, or more irridescent. Bill 17:53, 12 April 2006 (UTC)

Removed subsection

The subsection removed in this diff was a copy and paste from the link it contained, and I couldn't see anything granting the right the GFDL the text. - Taxman ^Talk 04:12, 1 July 2006 (UTC)

I've replaced the removed section with my own paraphrase of a different source. The subsection should be included, as it's an interesting way of placing concrete, but we shouldn't be copyvio here. Argyriou 05:19, 1 July 2006 (UTC)

Great, thank you. I didn't know enough to know if it was important enough, but I figured someone here would. - Taxman ^Talk 14:55, 1 July 2006 (UTC)

Discussion pertaining to worldwide useage and practice

Is there any disagreement about anything in the article? Gregorydavid 11:18, 26 May 2006 (UTC)

Although I am not responsible for the globalisation banner I appreciate why it's there, having read the article it comes across as US biased. Out of interest do you think there are enough editors with knowledge of concrete to give this article a real improvement drive? The basis is there but still alot of work to do, ie. no references, thoughts anyone? Grahams Child 20:53, 27 May 2006 (UTC)

I know a very little about non-US concrete practice, but engineering research into concrete is international, and my impression is that basic concrete practice is similar across the world. Argyriou 23:17, 1 June 2006 (UTC)

Yes, I think there is consensus worldwide regarding what constitutes good and bad practice, ie generally accepted practice by experts. "Concrete technology" focuses on mix design and related topics while "Concrete design" relates to the structural and stress related aspects of concrete usage.

So the article needs to refined a bit more..Gregorydavid 17:58, 9 August 2006 (UTC)

Concrete building techniques

There should be a section of concrete building techniques containing the techniques used in building with concrete such as:

pressurized concrete
prestressed concrete
as well as other techniques

Examples could be given aswell of other techniques such as those used in bunkers to strengthen the structure (or building).

This is Wikipedia, so you know what to do: be bold and start editing!

Atlant 12:36, 10 August 2006 (UTC)

Annual concrete production

The article says: As of 2005, over six billion tons of concrete are made each year, amounting to the equivalent of one ton for every person on Earth. Shouldn't it be six billion qubic metres (instead of tons)? According to Cement statistics (pdf), in 2002 the world production of cement was 1800,000,000 tons. Assuming 320 kg cement per qubic meter concrete in average, the concrete production in 2002 was 1800,000,000 / 0.32 = 5,625,000,000 m3 concrete. Mr. Carpenter 16:16, 11 August 2006 (UTC)

AfD Nomination: Eco-cement

The article Eco-cement has been listed at Wikipedia:Articles for deletion/Eco-cement. Please consider contributing to the discussion. Thank you. Argyriou 00:43, 24 August 2006 (UTC)

Length

As I was reading this article, I realized that it is rather long. It goes into greater detail than would seem (to me) optimal for Wiki.LorenzoB 04:36, 22 October 2006 (UTC)

External links

It seemed to me that the external links were mostly WP:SPAM. I pruned them, but may have deleted something useful. If so, it would be good to make it a WP:FN, instead of an WP:EL. --Walter Siegmund (talk) 04:28, 23 October 2006 (UTC)

Water impermeability and porosity

I'd be interested to know about the characteristics of concrete which relate to water impermeability and porosity. Some concretes are clearly very water resistant, and can be used to create ponds and lakes, while others are less so. Some concrete structures, even ponds, are coated with water resistant surface material to reduce leakage, or water penetration. One of the failure modes of reinforced or prestressed concrete is, I think, due to failure of the metal reinforcement due to water ingress. Concrete used to create foundations could retain a significant amount of water if allowed to become wet (after curing). It'd be interesting to have a few more pointers to all this. David Martland 17:33, 30 November 2006 (UTC)

Italic textThe permiability of concrete is controlled by it's porosity. As the water/cement ratio reduces, the products of hydration occupy more space within the matrix resulting in a lower porosity. At water/cement ratios greater than 0.38, there is not sufficient volume of gel formed to fully fill the space available to it and so leaves capillary pores. At water/cemet ratios less than about 0.7 (depending on the fineness of the cement used), the capillary pores will become discontinuous so reducing permiability if the concrete is allowed to mature sufficiently by wet curing.

Corrosion of the reinforcement can only occur if the concrete has carbonated which can be a slow process in a buried foundation. The design life of the structure can be easly met by ensuring adequate cover to the reinforcement and a sufficiently low water/cement ratio.

Severe vandalism

There has been severe vandalism by anon ip users to this article. [1] [2] [3] [4] --Parker007 02:52, 21 January 2007 (UTC)

Chemistry

Maybe there should be a section with the general chemistry in it... Sikkema 10:45, 22 January 2007 (UTC)

There may be a factual error in the carbonation section. The last line says if the crack is not an instance of carbonation (is still alkaline) a solution of phenolphthalein poured on the crack will turn violet. Generally phenolphthalein solutions are colorless in acid and pink (fuchsia) in basic (alkaline) solutions.

Smeaton/Portland cement

Since Portland cement was invented in 1826, John Smeaton couldn't have used it in 1756. Smeaton used various limes in mortar and concrete, and noted that the more argillaceous limes were more hydraulic. He also compared the color of his concrete to "good Portland stone", and so may have inspired Joseph Aspdin to name his 1826 product "Portland cement". But Portland cement, which was initially an ultra-fast setting stuccoing material, was not used in concrete until the modern, hard-burned product was introduced by William Aspdin in the 1840s. Click the links for more info on this. . . . LinguisticDemographer 22:18, 17 July 2007 (UTC)

Mix Ratios and Yields

I have scowered many web site and tech manuals but have failed to come up with a good description of how to mix concrete given the proper ratios of cement/sand/aggregate(gravel)/water. Many web sites work with either Metric or Pounds (Mass). These are not practical for the person who is preparing the mixture and is interested in Volume i.e.: How much cement/sand/aggregate(gravel)/water will produce how many m³ or ft³ etc.. Note that a sack of cement bought in the USA = 1ft^3 = 94 lbs = 42.6 kgs = .02832 m^3 while a sack of cement bought in Mexico = 1.17ft^3 = 110 lbs = 50 kgs = .03321m^3

The average (non-commercial) work site does not have a scale, but does have shovels, buckets, usually a mixer and a wheel barrow used to prepare and measure porportions.

Sam@leapofaith.net 02:20, 1 February 2007 (UTC)

Wikipedia is not an instruction manual. If you're mixing concrete on your jobsite, you should get a scale, or have a reasonably good idea of the bulk density of your sand and gravel, and do the volume conversions ahead of time based on some standard volume measure the jobsite will have, like 5-gallon buckets. Αργυριου (talk) 00:33, 4 May 2007 (UTC)

I agree that the wikipedia entry for concrete should have some basic information or examples of concrete formulas, such as the percentage (by weight) of cement, sand, and stone to make a typical batch. While it is said that the strength of a batch is determined by the w/c ratio, what is not mentioned is the c/a ratio (cement to agreggate ratio) or the sand/stone ratio. I make a typical batch as follows:

Cement: 23 lbs Stone (1/2" or 3/4"): 88 lbs Sand: 59 lbs

This gives a c/a ratio of 15.6%, and a sand/stone ratio of 67%. —Preceding unsigned comment added by 65.93.89.28 (talk • contribs) 04:19, 26 July 2007 (UTC)

A rule of thumb for home made concrete, I call it the "1, 2, 3 rule" (by volume): 1 part Cement 2 parts Sand 3 parts Stones 0.6 Water Add a bit of washing up liquid to improve workability.

What I'm doing

As those of you that may have been watching the history may have noticed, I'm attempting to slowly beat the article into a more readable, concise shape.

My current plans are more or less to smash most of the 'types of concrete' heading into one comparatively easy to understand at a glance table, listing major constituents (water, cement, aggregate, special features, uses) with a new types of concrete or similar article.

concrete failure modes swallows much of the cracking and environmental damage sections, with a short sentence or table detailing each of the failure modes.

Perhaps instead a concrete engineering practice entry, covering in a little more detail some aspects of this article, and also add more on crack control, stopping short of a full blown concrete-textbook.

Also more clearly separate cementatitious concrete from others in this article, highlighting differences and commonalities.

--Speedevil (talk) 05:41, 28 January 2008 (UTC)

Concrete vs Mortar

As it is defined now in this article there is no difference between mortar and concrete (check mortar article) other than usage when in reality mortar and concrete are different preparations. Mortar has only fine granulometry aggregate while concrete has both fine and coarse granulometry aggregates. Without the coarse aggregate the preparation is mortar not concrete. —Preceding unsigned comment added by 80.36.158.120 (talk) 02:54, 17 April 2008 (UTC)

Geopolymer green concrete

I added this section: I was surprised it wasn't mentioned here already as it seems to be the green-est concrete going. According to the manufacturer anyway. I moved the reference to the company to a footnote so as not to appear like an advertisement. But given that is where mostly the info came from and a tele-documentary, and, as they are they only ones making it commercially and not just academically, as far as I am aware, I think the footnote should stay. So by all means edit it but please dont DONT edit it out otherwise readers wont know where to go to find out more. (BTW: I have absolutely nothing whatsoever to do with the company or even the industry for that matter. (Although I would like to buy some of their stock ;-)) ) Regards, 122.148.173.37 (talk) 11:43, 22 May 2008 (UTC)

Missing Header?

I'm not sure, but is this article missing a header? --Kelvin_HO^{Wiknerd(talk)} 12:54, 23 June 2008 (UTC)

Plagiarised content

the entire hyrdation section, that has now been moved and appended to the section on water, appears to be plagiarised from http://www.understanding-cement.com/hydration.html. Schmidt455 (talk) 01:27, 3 August 2008 (UTC)

Blanked this - firstly it's plagarised - secondly, it's in way too much detail for a general article on concrete.

It should at best be on its own article. --Speedevil (talk) 22:09, 17 August 2008 (UTC)

Errors of Omission

re: Troll A platform

Totally amazing that the terms continuous forming or slip forming are missing and topically missing in the article. When you all take a sanity break, please connect the link Slip forming using an anchor or redirect to section, et. al. // FrankB 17:25, 2 October 2008 (UTC)

Cement trucks

Hi, I wonder if someone could answer a couple of trivia questions: 1) Is there something preventing concrete from hardening in those rotating cement mixer trucks, or are they just hoping that they'll get to their destination in time? 2) What happens if it does harden in there? Do they just discard the barrel, or is there some way to deconstruct it and get it off the concrete plug? Thanks! --Sean 20:56, 10 August 2007 (UTC)

The concrete has to be delivered and poured within a certain time. You can add additives that make the concrete dry quicker, slower, more dense, to make air bubbles, more fluid (SCC), ect… ect…

If the concrete has dried to much (still liquid) by the time it reaches a building site, the barrel will have to be emptied, back at the mixing plant (or in extreme cases where it stands).

--LJ 13:29, 12 September 2007 (UTC)

The concrete in the truck is usally a dry mixture, which cannot harden. The water is stored in a tank, which is behind the drivers cabin and is only added 15-20 minutes before the mixture is used up (so it can be mixed well). Should the concrete harden in the barrel, then workers can climb in through the small hole in the sid (which is usally sealed off) and break it up with a jackhammer. It's a hard job, but the truck is worth it. Hthomasxx (talk) 20:17, 9 December 2007 (UTC)

This is not commonly the case in California - concrete is batched wet and poured into the truck. Argyriou (talk) 05:55, 10 December 2007 (UTC)

Concrete is mixed in the drum. Water is not added once they get to the job. You have moisture in the sand so you already have a product where hydration has started. The mix is measured in what concrete producers call slump. Once the load is put into the truck the driver has to go straight to the job. Hoping there are no delays. Depending on the outside tempurature concrete is usually good for 90 minutes. But if it gets hot inside the drum the last edit is what can happen and that is not fun. —Preceding unsigned comment added by 214.13.3.165 (talk) 09:57, 15 January 2008 (UTC)

My dad told me that if a truck broke down and couldn't get to the job site or a place to dump the load, sometimes they'd put a lot of sugar in the load to prevent setting - i'm not sure how much they would use, would seem to need a lot. On the other hand, my dad also jackhammered and blasted a lot of concrete out of mixer barrels... --Wtshymanski (talk) 04:15, 20 December 2008 (UTC)

Merging "Concrete Curing" Article with "Concrete"

It has been recommended that I merge an article titled "Concrete Curing" with this article. How do I go about doing this and being sure it is done so correctly? ConcreteCuring (talk) 15:39, 7 January 2009 (UTC)

Welcome to Wikipedia. You should read all the tutorial material and style guides (starting at Wikipedia:Your first article) or at least look at them. The idea is that you want your contributions to look like the rest of the articles. The content at Concrete curing needs to be properly referenced to at least a couple of sources - you can do this with the <ref>...<ref/> . A "Power Point" presentation is not a good reference unless it's readily available (on the Web, say) - the point of references is that they are verifiable and accessible to other editors. Headings don't have semicolons at the end and are all lower case except tthe first word or proper names. Encyclopedia articles don't use second-person address so don't say "you will have a rough floor" etc. Try to avoid hyperbole - no need to say "enormous importance", strive for a dryer, less emotive and more technical tone - you're not selling anything here. Check for spelling errors and homonyms - you mean "effect", not "affect", for example. Redundancy - cut out needless duplication, for example you list the methods of accelerated curing twice and in very roundabout fashion. Dont say three (3)- this is redundant.

There's not much physical description of what is happening during concrete curing - the mechanism by which the cement paste gains strength by changing its crystalline form. It would be good to describe the chemistry and physics in some way, to give the reader an idea of the chemical changes going on as the concrete cures.

Properly boiled down, that whole article will make a very nice paragraph in this article, possibly even a heading of its own. And when you've finished, you can put a #REDIRECT [[Concrete]] at the top of the now-empty former Concrete curing article so anyone searching for that phrase will come to the Concrete article instead. ( Use "preview" to check your edits before you hit "save"!)--Wtshymanski (talk) 17:50, 7 January 2009 (UTC)

I'll do it in a couple of days probably. Much of it is already there, albeit spread around somewhat and merely needs additional mentions of carbon dioxide to it. It also has no citations, which I'll look for at the same time. It does have additional info - there isn't an explicit mention of misting equipment for example. --Speedevil (talk) 17:41, 7 January 2009 (UTC)

Self-repairing concrete

Self-repairing concrete (invented by Henk Jonkers) should be added in its own section. See http://www.citg.tudelft.nl/live/pagina.jsp?id=d6b29f69-f453-40e6-b6cb-01714077ed69&lang=en —Preceding unsigned comment added by 81.245.184.134 (talk) 15:19, 14 April 2009 (UTC)

Also mention that roman concrete was also self-healing. This as the potassium contained in it would fill up cracks after every shower. see [5]

Reactive Powder Concrete

I noted that the discussion on Strength (a subsection under Properties) listed information from an article that appeared in Wired magazine which implied that the highest strength concrete ever made might appear in bomb-resistant bunkers in Iran.

The article mentioned a student project that was entered in a competition in a way that was at best, anecdotal. But concretes of even higher strength have been prepared in the lab, have been featured in scholarly jounals, and have been patented. The Wikipedia article inspired me to research this, and almost all the higher-strength formulations that I found could be described as reactive powder concrete.

Perhaps this subject deserves its own Wikipedia article, or perhaps this should be moved to a new entry in this article in the "types of concretes" section. I did give a cite (and external link) to a 2003 paper that discuses RP concretes and gives the strength figure that I used. At any rate, the new "strongest concrete" information should be a little more authoritative than the Wired article.Eljefe3126 (talk) 18:23, 1 May 2009 (UTC)

CAN SOMEONE PLEASE ANSWER WHY ALL UNIT ARE NOT IN SI UNITS, I FIND THIS REALLY ANNOYING? I REALLY HATE AMERICAN UNITS, ITS A LITTLE BACKWARDS AND CAUSES ALOT OF CONFUSION DUE TO THE FACT THAT THE MAJORITY OF THE WORLD USES SI UNITS. —Preceding unsigned comment added by 81.153.78.104 (talk) 20:10, 17 May 2009 (UTC)

environmental issues

I have heard a couple of times that concrete is rather environmentally unfriendly and came here hoping to find out more. The article seems a bit lacking in this respect, apart from part of a sentence in the History section. This isn't meant as a complaint but as a suggestion for expansion.81.174.226.229 (talk) 10:01, 8 January 2008 (UTC)

If concrete is not used with common sense in the plastic state it can be a hazard to the enviroment. But once it sets it is used a protection layer for the enviroment. Do some searching on Pervious concrete. It is being used for alot of stormwater runoff. —Preceding unsigned comment added by 214.13.3.165 (talk) 10:01, 15 January 2008 (UTC)

I was referring more to quarrying and to the energy used (and carbon dioxide released) in its production.81.174.226.229 (talk) 10:20, 16 January 2008 (UTC)

I just watched a program (grand designs) that said the concrete industry created more co2 than the airlines and gave the frightening statistic of something like a ton of co2 per ton of concrete, however a quick search comes up with the website http://www.sustainableconcrete.org.uk/ which instead says The embodied carbon dioxide (ECO2) of a tonne of concrete varies with mix design and is in the range of: 75-176kg CO2/tonne to complete the topic the enviormental aspect has to be coveredBack ache (talk) 23:24, 27 March 2008 (UTC)

I think, but am not sure, that the CO2 produced in concrete manufacture comes from the making of the cement - the emission of CO2 during cement making and its reabsorption during setting and that the CO2 produced by the energy used in heating the limestone to 1500C is not included. Nor are the emissions created by transporting the stuff to site included. A paper to AWEA windpower conference at Houston June 2008 "Wind turbine foundations behaviour and design considerations" by Garrad Hassan America Ltd evidenced that a 3MW turbine requires a concrete footing of about 500 cu ft (i.e. about 325 tonnes) of concrete. Can anyone estimate what the carbon footprint of such a wind turbine might be - including the carbon cost of heating the cement as well as the emission and reabsorption of CO2 during manufacture and setting? Information such as this should be readily available here to inform decision makers. Or at least to prompt interest in the realities of the concrete industry. Lest this be thought to be a partisan suggestion - nuclear plants require a lot of concrete too! Fenton Robb (talk) 14:20, 18 July 2009 (UTC)

An alternative to concrete is Trass, its ecologic and feautures about the same strength/feautures as concrete (some advantages over concrete too as quicker hardening (3x quicker), elasticity, water density, drying, less skin-aggressive, ... ; include in article.

Thanks, KVDP (talk) 07:11, 13 May 2008 (UTC)

I came to this article looking for the same thing. This information should be incorporated into the article.--Yannick (talk) 15:56, 10 April 2009 (UTC)

Concrete Shelters

Concrete Canvas Shelters are rapidly deployable hardened shelters that require only water and air for construction. The 25sqm variant can be deployed by 2 people without any training in under an hour and is ready to use in only 24 hours.

The key to CCS is the use of inflation to create a surface that is optimised for compressive loading. This allows thin walled concrete structures to be formed which are both robust and lightweight. CCS consist of a cement impregnated fabric (Concrete Cloth) bonded to the outer surface of a plastic inner which forms a Nissen-Hut shaped structure once inflated.

The Need “While starvation occurs over a period of weeks, death from exposure can occur in a single night” UN Co-ordinator for Afghanistan

There are currently over 35 million refugees worldwide. The aid agencies and troops that help save lives in emergency situations require accommodation, field offices and medical clinics. Current solutions are either soft-skinned and offer inadequate protection, or are expensive and difficult to transport. For example, in Afghanistan the useable life of some tents has been less than 3 weeks due to wind damage. —Preceding unsigned comment added by 81.129.166.237 (talk) 16:28, 24 August 2009 (UTC)

Comment

Concrete was first incorporated by the Egyptians it is fairly relevant and easy to see due to the pyramids. not meaning to burst a bubble. In 3000 BC the Egyptians used mud mixed with straw to bind dried bricks. They also used gypsum mortars and mortars of lime in the pyramids. It was the first idea of concrete. i think that it should be in your history section. -a high school student in the middle of nowhere —Preceding unsigned comment added by 140.211.185.1 (talk) 17:43, 8 October 2009 (UTC)

Concrete failure

I've taken the liberty of moving this section to its own article. That's trimmed the article down to 59K from 68K. Josh Parris 00:39, 6 November 2009 (UTC)

Concrete Properties

I've moved this section, and the section on testing, off to Concrete Properties, reducing the article to 47K. Josh Parris 20:59, 28 November 2009 (UTC)

Self-consolidating concretes - how are they made?

Can the section on Self-consolidating concretes be expanded to include a little bit of detail as to what is done (or what is added) to create Self-consolidating concrete?

For example, is it just that more water is added, or more plasticizer, or some other "secret" ingredient? —Preceding unsigned comment added by 74.12.202.245 (talk) 23:34, 26 August 2008 (UTC)

Another new technology of self consolidating concrete is a product that is patened by Lafarge Concrete. The product is called Agilia and is used to form a smooth surface with no consolidation. It is also used for feature walls in many buildings or in areas with mass amounts of reinforcing steel and little space between bars. —Preceding unsigned comment added by Nerdo18 (talk • contribs) 18:22, 19 February 2010 (UTC)

concrete

do ashes from a fire that settle in a swimming pool damage concrete surface? —Preceding unsigned comment added by Shellsea (talk • contribs) 14:34, 11 March 2010 (UTC)

Problems

Footnote 50 does not lead to a article that has anything to do with what the proceding paragraphs were about. The preceding paragraphs talk about the merits of building with concrete while the footnote leads to an article on sound tranmission of concrete. These paragraphs sound like a sales pitch for someone who works in that industry and backed up with the shabby footnoting is entirely possible that it is an actual sales pitch by someone in the industry. —Preceding unsigned comment added by 142.162.17.236 (talk) 22:36, 16 March 2010 (UTC)

Oxygen absorption by concrete in the Biosphere 2 project building

the section "CO2 uptake by concrete in the Biosphere 2 project building" was originally about oxygen but someone deleted any mention of oxygen absorption and made it about CO2 absorption. Some thing (talk) 00:55, 28 November 2009 (UTC)

This diff shows User:Shinkolobwe made the change you're complaining about; the comment was "(→Oxygen depletion: Rename: the title of this section is misleading: per se, concrete does not absorb oxygen, nor deplete the atmosphere in O2)". Have a chat with them and find out why the change was made. Josh Parris 01:24, 28 November 2009 (UTC)

I modified this section simply because the content was likely wrong. Chemically, concrete aging cannot absorb molecular oxygen. At the contrary, portlandite, Ca(OH)₂, present in cement can easily undergo carbonation with CO₂ present in the air to produce CaCO₃. As a consequence, it affects the mass balance calculations of the photosynthesis / respiration processess taken into account in the biosphere project. The only physical process able to trap O₂ could be the physical adsorption of oxygen gas onto the CSH minerals present in the concrete, or O₂ dissolved in the cement porewater. In my opinion, these two last processes are minor and could be omitted without problem in the model simplification. Anyway, if any, the exact process possibly responsible for the observed artefact in the biosphere project should be clearly mentioned and documented in a verifiable and understandable way. Moreover, I think that this information should be best given and discussed in the biosphere project itself where it is relevant to the context than in the page on concrete where it appears very anecdotic and misleading. The more misleading point is that by reading this original section a "non-scientifically educated" normal reader could easily imagine that oxygen in a close and confined space could be simply depleted by its interaction with the concrete to hypoxic conditions and presents a safety risk. If I missed a an important point, I would be pleased to understand the real processes at work for a direct oxygen capture into concrete. Best regards, Shinkolobwe (talk) 11:08, 9 May 2010 (UTC)

project to be carried out

i have project on this topic to carry out "the effect of the prolonged mix on the effect of the concrete". Help me out. —Preceding unsigned comment added by 204.106.8.56 (talk) 10:44, 28 August 2010 (UTC)

Pre-roman, Roman and Medieval Concrete

I have a book that explains the whole topic of Roman Concrete. Roman concrete was a mixture of quicklime and pozolan. Quicklime had already been used as a mortar, but when pozolan was added, the romans discovered that the resulting mixture had hydraulic properties, in other words, the concrete would set underwater. Since quicklime is more flexible than modern day portland cement, roman constructions have lasted 2000 years without the need for expansion joints.

Should we add a seperate topic for roman concrete? -- Dullfig 19:47, 11 February 2006 (UTC)

Probably just fleshing-out the subheading would suffice. If you wanted to get really technical, you could fill a book with it (but then it wouldn't be an encyclopedia entry anymore). I did a project on ancient Roman concrete for one of my masters courses. --King aardvark 18:08, 24 February 2006 (UTC)

Roman concrete is a very important topic (I would rather know about it than all of the boring modern crap) which deserves a full section. — Chameleon 07:31, 15 August 2007 (UTC)

The Italian word for concrete is calcestruzzo, which is lime ostrich. Why do the Italians consider concrete to be lime ostrich please? Thank you for helping me to understand this. --Prospect Vale 19:47, 21 October 2007

Not exclusively roman:

We have example of hydraulic cement after the fall of Rome and before the advent of Portland cement. In

Znachko-Iavorskii, I.L., New Methods for the Study and Contemporary Aspects of the History of Cementing Materials. Technology and Culture, Vol. 18, No. 1, 1977, the author describes a great deal of hydraulic lime mortar from all over the world before and after the fall of Rome, made from a startling variety of materials - things like egg whites, cheese and sour cream were used to achieve it. He has recipes from the high medieval period, and analysis of 11th century mortars that could set under water. The section detailing the uniqueness of roman concrete should be modified.

I have removed the non-sequitur that suggested a "continuous" use of concrete since Roman times on the evidence that the Canal du Midi was constructed using concrete in the 17th c. How do we possibly go from the proposal that concrete was lost for 13 centuries to "continuous use" on the evidence from du Midi? All this does is suggest it was lost not for 13 but 12 centuries. The evidence from Finland, if cited, could push it back one more century. The material on the Middle Ages discussed above should be added - this will fill out the history much more. But we are still far away from reputing the idea that the knowledge of concrete was lost and rediscovered. —Preceding unsigned comment added by 24.91.119.28 (talk) 01:21, 27 September 2010 (UTC)

concreat/yard

how do you fig out how many yards you need for a job? —Preceding unsigned comment added by 72.161.56.55 (talk) 00:22, 28 April 2009 (UTC) L in feet) x W (in feet) x H (in feet) / 27 BobV01 (talk) 04:00, 8 November 2010 (UTC)

Neutrality of section "building with concrete"

I am a bit suspicious of the section "Building with concrete" , it sounds a bit too much like a massaged press release from the concrete industry. This press release seems to contain many of the facts repeated in the section of the article. I'm not saying the facts are necessarily wrong, but I think they need to be at least reworded, trimmed down and tagged with more citations. I'll work on it when I have time, but if someone wants to have a crack at it before me then please feel free! — QuantumEleven 14:20, 17 August 2010 (UTC) Concrete Masons, Engineers, Fire Protection Officals, Hurricane/Wind Stress Officals, Architects and Designers and Planning Officals seem also to use the same lanquage: I would bet that after endless seminars, AGC, AIA, SI, and NFTB working groups not to mention AIS who love to standardize various properties: there probably has become s standard set of describtors for concrete and that roten concrete industry had the unmitigated gall to use it in apress release. Despite having vital information butchered out for the sake of memory consumed here in one shot, one place, one page is a rather comprehensive treatment of most of the body of inquiry into the field. The nit picking and whining over this as I read it here is amazing to me. Hatsoff to he who started this, was patient and perserverant I humbly suggest the nuetrality challenge be resolved that nuetrality exists as described at Wiki and the flag and challenge be removed BobV01 (talk) 02:44, 8 November 2010 (UTC) I removed the NPOV template BobV01 (talk) 04:02, 8 November 2010 (UTC)

Melting temperature?

Does someone know sources at which temperatures concrete could melt or break due to heat? Thx. --Trofobi (talk) 18:40, 17 March 2011 (UTC)

It is a complicated issue: there is typically a lot of water in the cement pores, and therefore when exposed to fire, concrete tends to spall. The behaviour will also differ depending on whether the concrete is reinforced or not: heat will soften the reinforcement bars, which might lead to structural problems. Cement itself will start to decompose at around 420 °C, and have completely decomposed at around 1000 °C. The temperature at which the aggregates in the concrete will melt is much higher.CyrilleDunant (talk) 19:13, 17 March 2011 (UTC)

Thanks a lot :) Yes, difficult to tell, one has to know the specific composition. I just looked up the melting ponits of some minerals and the temp. range of Magma. Then finally found this: Corium (nuclear reactor)#Corium-concrete interactions The fast erosion phase of the concrete basemat lasts for about an hour and progresses into about one meter depth, then slows to several centimeters per hour, and stops completely when the melt cools below the decomposition temperature of concrete (about 1100 °C). Complete melt-through can occur in several days even through several meters of concrete; the corium then penetrates several meters into the underlying soil, spreads around, cools and solidifies. (Ref: Jacques Libmann (1996). Elements of nuclear safety. L'Editeur : EDP Sciences. p. 194. ISBN 2868832865.) --Trofobi (talk) 19:41, 17 March 2011 (UTC)

Sources, Images, Advert like

Can sources that are susceptible to bias be avoided eg [6]. Also please place images into relavent sections, not randomly, and do not add so many images that they extend beyond sections causing formatting problems.Imgaril (talk) 17:17, 23 July 2011 (UTC)

Also advert (diff) reads like an advert for concrete construction. Concrete isn't flammable.Imgaril (talk) 17:39, 23 July 2011 (UTC)

Also Repair diff this section was not about concrete repair generally, but about concrete road repair -too specialised - moved to Road surface. A section on repair might be a good idea by the way.

Apart from the haircut and few flaws I like the article , well done :) Imgaril (talk) 17:43, 23 July 2011 (UTC)

Environmental impact of concrete

I've taken the liberty of splitting off the Environmental and health section off into a new article Environmental impact of concrete. This has brought the article size down to 149 kB, with Prose size (text only): 25 kB (4047 words) "readable prose size" Josh Parris 08:35, 12 January 2012 (UTC)

Not neutral, many citations needed

I think that such a ubiquitous and amazing material such as concrete should get the proper Wikipedia treatment it deserves. This article seems a bit too biased toward the wonders of concrete, and many statements are lacking citations. I feel that the article is extremely biased in favor of concrete and should be made a bit more neutral. — Preceding unsigned comment added by Kosmoraios (talk • contribs) 02:31, 9 March 2012 (UTC)

You are probably right, but do not forget that Wikipedia is often maintained by specialists working in the field and sharing their knowledge, and so they are also often quite enthusiast. Enthusiasm is probably the driving force of Wikipedia and nothing is perfect. But I agree, citations are always needed and it can be improved. Best regards, Shinkolobwe (talk) 15:27, 18 March 2012 (UTC)

electrical properties?

This is an interesting entry, everything I could possibly want to know about concrete except for electrical properties. Houses now require putting a "ufer?" ground for the electrical panel so I assume concrete conducts to some extent. Could somebody who knows about concrete electrical properties please add this? Thanks! Paul Kinzelman (talk) 03:25, 18 June 2008 (UTC)

IIRC, the National Electrical Code requires that the metal rebar in poured concrete must be tied into a building's electrical ground system. I don't recall if this is in addition to a copper rod driven into the earth as the grounding electrode, or if the building's rebar could -be- the grounding electrode. In any event, the purpose is to make sure that an electrical fault can't energize the frame of the building so that just touching a piece of metal (steel frame or steel 2x4) won't give you a shock. --Paul E Musselman Paulmmn (talk) 16:38, 18 April 2012 (UTC)

Fire safety niggle

There have been a few attempts to qualify the statement that concrete does not burn (not authored by me btw!). For example, one tried to introduce electric fires as an exception. All these have been reverted, and of course, correctly so. I am however bothered because although concrete will not burn under normal circumstances (we are not after all concerned with special cases such as fluorine atmospheres or cesium baths) there is a functional reservation at issue, namely the nature of the limitations of the resistance of concrete to fire hazards. Irrespective of red herrings, such as whether concrete burns or not, it seems to me that the article lacks substantial discussion of the topic of fire resistance, which has only contingent relevance to the question of combustion as such. Even in the article on the Collapse of the World Trade Center there is very limited discussion of that aspect of the topic. I strongly urge that some editors with expertise in the matter or with information available on the topic, contribute a coherent discussion of the matter to this section. If it already has been discussed adequately in some article that I am not aware of, then at the very least there should be a link to such an article. I don't mind assisting if anyone is interested in such a topic, but it is not my field of expertise, so I hesitate to undertake it on my own authority. JonRichfield (talk) 07:48, 10 October 2012 (UTC)

Slump

I have a real problem with the rules of thumb for improving slump in this article. Slump should NEVER be increased by arbitrarily adding water - it is extremely bad practice. If concrete doesn't have the right slump then it should be rejected, and a concrete with the required slump ordered from the producer. Alternatively, if you are making the concrete yourself, you again reject the concrete and adjust the mix proportions to get the slump you want. Does anyone agree that it should be deleted? —The preceding unsigned comment was added by Kpeyn (talk • contribs) .

Increasing a slump by adding a water will increase w/c ratio, lower the strength, and increase concrete penetreability reducing thus its durability. Slump may be increased during concrete mixing by adding superplasticizers and water reducers (see eg. Concretenetwork.com). petr.konec 21 August 2006

It all depends on what you're doing. If you are using concrete or another cement-based material in an application where strength doesn't matter (say, for fill around a temporary pile) then increasing the slump by adding water is perfectly acceptable. Not all concrete is used in important, permanent structures.

Why complicate the things. The information on wekipedia should be relevant to most of the common examples and should give the universal truth; that the strength , durability of concrete drops with increase in water / cement ratio.One should not give an examples of a very very rear usage of concrete such as fill around a temporary pile. — Preceding unsigned comment added by Cdcpune (talk • contribs) 07:55, 26 October 2012 (UTC)

Disputed neutrality?

Okay, I recently found a cool source of concrete/cement references. (Yes, I understand 'concrete' and 'cool' don't really mix, I have strange interests, sue me.) So I decided to pop over to this article and cite away....

And there's a point of view tag? On CONCRETE?

I read the talk page, and the editor that put the tag on did not explain what was non-neutral. So, I thought I'd post here to see if we can get some discussion going about how to improve this topic.

Concrete? Not-neutral? I just don't get it. Please clarify.

Morg00 (talk) 05:07, 8 January 2013 (UTC)

History section could be improved by details about widespread adoption

The history section focusses more on exceptional early uses and doesn't really address the question of when and how concrete became commonplace. True the Romans had it and there might be occasional buildings from the 1600s, but still most buildings I know from 1900 were brick while buildings from the 1950s were often concrete. How did this change happen? Andrew Hennigan (talk) 16:31, 5 August 2012 (UTC)

I also came here looking for the same thing and didn't find it. When & how did we make the widespread transformation from wood or stone foundations to concrete? When did it become a mainstream building material? When did we start using it everywhere as flatwork in our homes? When did it begin widespread use for paving roads?--Tom Hulse (talk) 19:18, 17 October 2012 (UTC)

To quote the Wikipedia article on Robert Maillart "The first use of concrete as a major bridge construction material was in 1856. It was used to form a multiple-arch structure on the Grand Maître Aqueduct in France. The concrete was cast in its crudest form, a huge mass without reinforcement. Later in the nineteenth century, engineers explored the possibilities of reinforced concrete as a structural material. They found that the concrete carried compressive forces, while steel bars carried the tension forces. This made concrete a better material for structures". Robert Maillart was a Swiss engineer who pioneered the use of reinforced concrete construction. From this we can see that the use of concrete for structural engineering definitely started within 30 years of the development of Portland Cement. Everybody got to be somewhere! (talk) 23:58, 19 February 2013 (UTC)

Eugène Freyssinet took concrete design a step further by developing prestressed concrete. He was active in the first half of the 20th century. He was a graduate of France's École Nationale des Ponts et Chaussées, an institute that has played a pre-eminent role in structural engineering since Napoleonic times. Everybody got to be somewhere! (talk) 00:10, 20 February 2013 (UTC)

"a complex mixture of not entirely negative effects"

Are you kidding me? The hell is that even supposed to mean? It's in this article twice and also in Environmental impact of concrete but it's uninformative and borderline ridiculous. 64.229.236.8 (talk) 13:21, 15 January 2013 (UTC)

You can't be serious; it is not at all borderline ridiculous. I did a bit of damage control. JonRichfield (talk) 06:21, 15 March 2013 (UTC)

concrete forms/removable forms

Bulleted list item

Numbered list item

for thousands of years concrete forms were "tacked" together with nails or cut to interlock so as to hold the wet concrete in the desired shape until the curing could occur. when special finished look was desired the forms needed to be removed quickly w/o damage to the finish so the duplex head nail was invented and used extensivly for over a hundred years "sez thomas hunt, hunt construction escondido ca." then in 1983 a nubie superintendent to the construction field brought to the job site a 7.2v battery powered screw gun and proceded to teach the undocumented labors in his concrete crew the new way to put the forms together with screws . his name is roger jimerson an inventor of many work saving tools tequnics and systems 184.76.106.221 (talk) 05:26, 11 December 2013 (UTC)--184.76.106.221 (talk) 05:26, 11 December 2013 (UTC)--184.76.106.221 (talk) 05:26, 11 December 2013 (UTC)--184.76.106.221 (talk) 05:26, 11 December 2013 (UTC)--184.76.106.221 (talk) 05:26, 11 December 2013 (UTC)

Concrete articles

Please see WT:ARCH#Concrete articles. Simply south...... disorganising disorganisation for just 7 years 12:01, 25 January 2014 (UTC)

Worldwide CO₂ emissions and global change

The following content was vandalised. I copy it as a backup and also for verification and further development of this information. Comments and additional information are welcome. Shinkolobwe (talk) 10:37, 9 May 2010 (UTC)

The cement industry is one of two primary producers of carbon dioxide (CO₂), creating up to 5 percent of worldwide emissions of this gas. The embodied carbon dioxide (ECO₂) of one tonne of concrete varies with mix design and is in the range of 75 – 175 kg CO₂/tonne concrete.^[1] The CO₂ emission from the concrete production is directly proportional to the cement content used in the concrete mix. Indeed, 900 kg of CO₂ are emitted for the fabrication of every ton of cement.^[2] Cement manufacture contributes greenhouse gases both directly through the production of carbon dioxide when calcium carbonate is thermally decomposed, producing lime and carbon dioxide,^[3] and also through the use of energy, particularly from the combustion of fossil fuels. The cement industry produces 5 % of global man-made CO₂ emissions, of which 50 % is from the chemical process, and 40 % from burning fuel.^[4]

References

^ http://www.sustainableconcrete.org.uk/main.asp?page=0
^ Mahasenan, Natesan (2003). "The Cement Industry and Global Climate Change: Current and Potential Future Cement Industry CO₂ Emissions". Greenhouse Gas Control Technologies - 6th International Conference. Oxford: Pergamon. pp. 995–1000. ISBN 9780080442761. {{cite book}}: |access-date= requires |url= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ EIA - Emissions of Greenhouse Gases in the U.S. 2006-Carbon Dioxide Emissions
^ The Cement Sustainability Initiative: Progress report, World Business Council for Sustainable Development, published 2002-06-01

Carbon Capture and Storage

Deletion of a non-sense or confuse phrase:

"Another approach is by making the concrete using a biocatalyst called carbonic anhydrase.^[1]"

References

^ Use of carbonic anhydrase in concrete production

This does not make any sense ! The reader will think that the carbonic anhydrase enzyme is used as a catalyst specially incorporated into cement or concrete to facilitate the CO₂ uptake by the hardened cement paste. Portlandite and alkaline oxides have a sufficient high affinity for CO₂ that this is not necessary to accelerate it.

Moreover:

Concrete carbonation is a diffusion-controlled process detrimental for the corrosion of steel reinforcements and reduces the service life of the installation.
No enzyme can work in the solid phase, and certainly not at very alkaline pH (12.5 – 13.5). Indeed, enzymes need water and conditions under which their are not desactivated or hydrolysed.

After verification of the citation, it appears that the carbonic anhydrase enzyme could be used in CO₂ scrubber system specially installed behind the kiln at the cement factory in place of amine in order to more efficiently trap the CO₂ with less energetical expenses. Anyway it is related to a capture system designed to trap CO₂ directly at the outlet of the clinker kiln and not to an admixture to be added to the concrete.

Any contributor adding an information to this page should at least understand himself the basic processes or phenomena with a minimum of knowledge. Or perhaps it was simple vandalism. Shinkolobwe (talk) 14:38, 3 July 2010 (UTC)

The reference that was cited leads to the "CO2 Solutions" website, but the page linked to has now been deleted. Apparently not even the CO2 Solutions people could stomach the nonsense. Thanks for cleaning this out. 42GeoCPU (talk) 15:31, 25 August 2014 (UTC)

Bad section

Removed this : diff

===Environmentally sustainable=== With its 100-year service life, concrete conserves resources by reducing the need for reconstruction. Its ingredients are cement and readily available natural materials: water, aggregate (sand and gravel or crushed stone). Concrete does not require any CO2 absorbing trees to be cut down. The land required to extract the materials needed to make concrete is only a fraction of that used to harvest forests for [[lumber]]. [[File:BathsOfCaracalla.jpg|thumb|The [[Baths of Caracalla]], Rome, Italy, in 2003.]] Concrete absorbs CO2 throughout its lifetime through carbonation, helping reduce its carbon footprint. A recent study<ref>Nordic Innovation Centre Project 03018 http://www.nordicinnovation.net/img/03018_carbon_dioxide_uptake_in_demolished_and_crushed_concrete.pdf {{dead link|date=April 2011}}</ref> indicates that in countries with the most favorable recycling practices, it is realistic to assume that approximately 86% of the concrete is carbonated after 100 years. During this time, the concrete will absorb approximately 57% of the CO2 emitted during the original calcination. About 50% of the CO2 is absorbed within a short time after concrete is crushed during recycling operations. Concrete consists of between 7% and 15% cement, its only energy-intensive ingredient. A study<ref>Pentalla, Vesa, Concrete and Sustainable Development, ACI Materials Journal, September- October 1997, American Concrete Institute, Farmington Hills, MI, 1997</ref> comparing the CO2 emissions of several different building materials for construction of residential and commercial buildings found that concrete accounted for 147 kg of CO2 per 1000 kg used, metals accounted for 3000 kg of CO2 and wood accounted for 127 kg of CO2. The quantity of CO2 generated during the cement manufacturing process can be reduced by changing the raw materials used in its manufacture. A new environmentally friendly blend of cement known as Portland-limestone cement (PLC) is gaining ground all over the world. It contains up to 15% limestone, rather than the 5% in regular Portland cement and results in 10% less CO2 emissions from production with no impact on product performance. Concrete made with PLC performs similarly to concrete made with regular cement and thus PLC-based concrete can be widely used as a replacement. In Europe, PLC-based concrete has replaced about 40% of general use concrete. In Canada, PLC will be included in the National Building Code in 2010. The approval of PLC is still under consideration in the United States.

Trying to present concrete as enviromentally friendly in the manner above is wrong. It's a joke. A few points may have been fair, such as the long service life. Fluff articles such as "Concrete and Sustainable Development" from the "American Concrete Institute" aren't acceptable either, as there are clear issues with bias. No thanks.83.100.181.138 (talk) 16:13, 23 July 2011 (UTC)

I agree that that text was a bad sample of fluff, but the response was not a lot better; the wording, no doubt inadvertently, suggests unconditional aversion to concrete. I would have found the remark and action more favourably impressive if it had been associated with a more balanced discussion of the same information. I assume that you were too busy, but aren't we all? (I btw have no connection with any concrete related industry whatsoever, which takes a bit of doing nowadays! Nor do I have the least idea who contributed the material in the first place.) I'll try to remember to look in with better material, but I obviously am not the best person for the job. JonRichfield (talk) 08:50, 13 April 2012 (UTC)

I have to say that the justification for completely removing the material is much more biased than was the material removed. The material was not a joke. Much better to have adjusted the wording for a more balance presentation. Would one reject NASA sources for material about NASA projects? No. So why reject ACI sources for material about PCC? FYI, I'm a geologist and civil engineer that currently works for a state DOT managing research in geotechnical, hydrologic and environmental subject areas. I don't have a horse in the merits and demerits of PCC, but I am in a position to be well informed about the material and its environmental issues. The wholesale removal of the passage in question was biased censorship, plain and simple. The article has evolved since the removal and the topics addressed in the removed material seem to be addressed in the current article. I just hope that in the future, flawed reasoning such as used by 83.100.181.138 isn't accepted. 42GeoCPU (talk) 15:56, 25 August 2014 (UTC)

Cement versus concrete

Since cememt is redirected to concrete, could someone give the differences between the two perhaps structurally and in their uses? 69.181.82.210 06:01, 30 August 2005 (UTC)

Concrete is the complete mixture: Portland cement, water, the aggregate (for example, crushed rock), and any other additives.

Technically speaking, cement is just the Portland cement that glues the aggregate together. But it's often used colloquially (and incorrectly) as a synonym for concrete.

Atlant 14:22, 30 August 2005 (UTC)

Redirection of Cement is fixed. The Cement topic is up and running again.
Oyvind 17:09, August 30, 2005 (UTC)

Portland cement concrete is the default meaning of "concrete" in this context, but there are other types of concrete. For example, asphalt is sometimes called "bituminous concrete". Polymer concrete uses resins as the binder/cement; cultured marble, which is commonly used for bathroom sinks, is one example of polymer concrete. --Leo Schlosberg 21:07, 3 November 2005 (UTC)

If portland cement was invented in 1824, how could smeaton have pioneered the use of it in concrete in 1756?

The romans pioneered concrete even before that. You don't neet portland cement to make concrete. -- Dullfig 17:54, 27 February 2006 (UTC)

Just to wrap this one up, "Cement" no longer redirects to "Concrete" in Wikipedia. It never should have, because they are far from interchangeable terms.42GeoCPU (talk) 16:16, 25 August 2014 (UTC)

Section on Cement now duplicates information in that article

The information in the section "Cement" duplicates to a great extent information in the main article "Cement". Also, the section on "History" has a great overlap with the "History" section in the article "Cement". Since this article is already very long, and since an article on cement already exists, it would seem reasonable to me to edit down the information in the cement section in this article (ensuring of course that all relevant information is migrated to the article "cement"). By the way, it seems to me that, in history, the key innovations and developments have been in cement (the binder for concrete), with the exception of the introduction of reinforcement (the key development in the history of concrete). Should not the history section of this article be cleaned up with this distinction in mind?ArthurOgawa (talk) 17:32, 31 October 2014 (UTC)

Portland cement and PC concrete are very tied together. In general it is acceptable to repeat the information in two articles. The article is long however but it does not seem like any section is all that long. I would say that I slightly oppose the idea, but could be convinced it is a good idea. XFEM Skier (talk) 18:32, 31 October 2014 (UTC)

Thanks for weighing in. Here's my perspective: at present, particularly in the area of High Performance Concrete, we are now at a point where many of the elements of "standard" concrete and cement now have alternative forms.

For example, reinforcing material for concrete (rebar) has been predominantly steel. However, as the article on rebar mentions, there is now on the market (and moving towards certification) an alternative "basalt rebar", which is composed of rods formed of multiple fibers of basalt filaments. This reinforcing material, because it does not corrode, is not electrically conductive, and so on, is transforming concrete in a number of ways (in particular, the requirement for the rebar to lie a minimum of 3 inches from the surface of the concrete, a requirement stemming from the need to protect the steel from chloride ions).

As another example, geopolymer concrete, which uses geopolymer cement as its binder, offers a (chemically distinct) alternative to concrete that uses Portland cement as its binder. So, we have to consider that Concrete cannot be assumed to employ Portland cement as its binder, and Reinforced concrete cannot be assume to use steel as its reinforcment. In an article with a generic title like Concrete, or Cement, we must not fall prey to assuming that the former must refer to Portland-cement concrete and the latter to Portland cement.

Untangling these assumptions from our writing will be an essential step in keeping the wiki up to date in a field with a lot of innovations taking place. Have I convinced you of the merit of separating out the information on the (Portland) cement binder from the article on concrete?ArthurOgawa (talk) 22:32, 2 November 2014 (UTC)

Substituted transclusion for File

I substituted a transclusion of Template:Components of Cement, Comparison of Chemical and Physical Characteristics for File:Comparison_of Chemical and Physical Characteristics Portland Cement - Fly Ash, Slag Cement, and Silica Fume.jpg, which had been flagged for translation to SVG, as if it were a graphic. But since it is really a table, I have re-rendered it in wiki markup. The references cited in the table have been freshly extracted from the source document of the table. I have done this change for each of the three articles in which that file was referenced (Concrete, Cement, and Silica fume).ArthurOgawa (talk) 23:24, 6 November 2014 (UTC)

Nice work converting those graphics to tables, but is main article space really the right place for that template page in its current form? --jnkyrdsprkl (talk) 00:38, 7 November 2014 (UTC)

No. I was going to move it to the Template namespace. Just haven't done it yet. – JBarta (talk) 01:13, 7 November 2014 (UTC)

Done. – JBarta (talk) 01:21, 7 November 2014 (UTC)

@Junkyardsparkle: Putting the transclusion in the wrong namespace was due to my lack of experience, and I have learned a lot. @Jbarta: Thanks for fixing things up. ArthurOgawa (talk) 05:44, 7 November 2014 (UTC)

No problem. Good idea and nice work. – JBarta (talk) 05:57, 7 November 2014 (UTC)

Types of concrete

I've taken the liberty of splitting the Types of concrete section off into its own article, shaving the 88K article down to 68K. I think more work may need to be done. Josh Parris 05:07, 5 November 2009 (UTC)

Could you possibly do a page on Ductile concrete by Lafarge. It is a relevtivly new product and has many qualities normal concrete does not. —Preceding unsigned comment added by Nerdo18 (talk • contribs) 18:26, 19 February 2010 (UTC)

I think that moving the lengthy list of concrete types is a good improvement. This change has, however, contributed to a general problem with the article. It is almost exclusively about Portland Cement Concrete (PCC) and could easily leave a reader with the impression that "concrete" is interchangeable with "PCC." I've edited the cement paragraph under "composition of concrete" to emphasize that Portland Cement is only one of many cements used to make concrete. I think the overall article remains too PCC centered.

I would like to propose that much of the material in the current "Concrete" article be moved to a new "PCC (Portland Cement Concrete)" article so as to make the "Concrete" article more balanced for the broader, true meaning of the term concrete.

Does anyone have any thought about such a proposal? 42GeoCPU (talk) 15:05, 25 August 2014 (UTC)

@42GeoCPU. I for one would very much favor clarifying the matter. In my reading, I have received the impression that the essence of Concrete is aggregate plus binder plus (optional) reinforcement. In modern practice, each of the three components vary quite a bit. Of particular relevance is variation in the binder, usually called Cement. The article on Cement should itself contain the details about the various options here, and the article on Concrete should focus on the variations centering on aggregate and reinforcement. To be complete, water for all practical purposes has to be considered a component of concrete, though it is really a component of the cement.

There are additional materials added to concrete that do not fall squarely in any of these three categories. However, of those listed under Chemical admixtures, Accelerators and Retarders are really modifiers to the cement rather than to the concrete itself. Notwithstanding that they may be added to the mix rather than blended with the binder. Especially egregious are those listed under Mineral admixtures and blended cements. All are more properly regarded as modifiers to the binder (implicitly Portland Cement). I will support my opinion by pointing out that all of the materials listed—Fly ash, slag, silica fume, and metakaolin—react chemically with the Portland Cement and support the binding process. Writings about concrete are notoriously confused about this distinction. If you look carefully at these four materials, all have silica (metakaolin also contains alumina), and these mineral components participate in the chemistry of cement hardening on an equal footing with Portland Cement.

Historically, binders of various types have been used to bind together building materials dating to ancient time. Types_of_concrete#LimecreteCob construction used slaked lime Ca(OH)₂, which hardens into calcium carbonate; modern construction employs the binder known as Portland cement involving added silica and producing (insoluble) calcium silicate hydrate; and Geopolymer_cement involves alternative materials, producing a "poly(sialate-siloxo) cross linked network".

At the same time, variety in reinforcements has proliferated. Besides steel reinforcing bar, they now include the use of fibers of several kinds, both metal and plastic.

My recommendation for the article Concrete would be to split out (conceptually) the matter of the binder so the article can concentrate on concrete per se.ArthurOgawa (talk) 18:38, 7 November 2014 (UTC)

Iran develops ultra-high-performance quartz-infused concrete

Stumbled onto this. I don't know if it's new news or old news... but there it is. – JBarta (talk) 23:08, 19 November 2014 (UTC)

That article apparently traces back to The Economist: Bunker-busting Smart concrete dated Mar 3rd 2012, recounting research in Iran on Types_of_concrete#Ultra-high-performance concrete. The article refers to Silica fume as “quartz flour.” The quartz seems to be a typical ingredient of UHPC. A review article from the US Federal Highway Administration on UHPC ArthurOgawa (talk) 04:49, 20 November 2014 (UTC)

Fire Safety

This section includes discussion of ICFs (2nd para), and info on resistance against externally applied forces (3rd para).

The statement "ICFs ... made of fireproof insulating foam" is untrue. The foam must be protected against fire - see the main ICF article.

Suggest that the para on ICFs be moved from Fire Safety to its own section, and be edited for accuracy re fire resistance.

The info on resistance against externally applied forces is generally accurate, but it is misplaced - it has nothing to do with Fire Safety.

Suggest that it be moved to a new section.

PMJzz (talk) 18:41, 8 April 2015 (UTC)

Service life

On the article, it is written "100-year service life". An architect gave me an estimation of 70 years. I was not able to find any estimation on the web (apart from some concrete sellers who claim that it is more that 1000 years, taking the roman architecture as an example!). Can someone here provide a link to a serious reference for this?

Also, no estimation is given in the specialized article Concrete degradation http://www.concrete.org/FAQ/afmviewfaq.asp?faqid=20 BobV01 (talk) 02:59, 8 November 2010 (UTC)

Concrete is rock. It can last forever if used properly and protected, and destroyed in a minute if abused.[7] Delphi234 (talk) 18:05, 9 January 2013 (UTC)

I'm certainly no expert in this field, but concrete is not "rock." For one thing,it is made of artificially cemented materials. For another, when comparing concrete's strength and durability to rock are we talking igneous, metamorphic or sedimentary? Rocks vary widely in their strength and hardness . They range from shale you can scratch with a fingernail to extremely rare minerals like wurtzite and lonsdaleite, which respectively, withstand 18 percent and 58 per cent more stress than diamond. ^[1] If I had to place a bet, I'd certainly bet on the Pyramids at Giza, already 4,500 years old, outlasting the concrete used in the Empire State Building.Un Mundo (talk) 02:51, 19 November 2014 (UTC)

User Delphi234 cited an article in [about.com] to support the statement that “Concrete is rock.” That article states that concrete is a synthetic, biogenic conglomerate bound together by a mineral glue; one could therefore make the case that concrete is rock, albeit biogenic. A similar material, though natural, is the sandstone in the Navajo Sandstone formation; it is quartz sand bound together by an iron-bearing substance (which is the source if its red hue). This material is easily degraded by environmental factors (anything that dissolves that iron oxide), just as Portland cement-based concrete is degraded by numerous environmental factors. To say, as Delphi234 does, that “It can last forever if used properly and protected” constitutes a vacuous statement: many things fall in this category, not just concrete. Little of this comment addresses the question of the Service Life of concrete.

What I have seen in my reading about concrete is that it is commonly claimed to have a service life of some 100 years. But this claim has been found not to be borne out by practical experience, which shows concrete deterioration that terminates its service life after only 50 years. In my opinion, a fairer statement of the service life of a particular concrete installation would be “indefinite”; a more candid statement would be “we do not know.” The WP article on Concrete degradation#Carbonatation makes it clear that the omnipresent atmospheric CO², in giving rise to the process called carbonatation, degrades a concrete that is reinforced by steel. So the service life of the concrete of common use (employing Portland cement binder) cannot be considered "forever" even when the material is “protected”.

User BobV01 cited the claim of 1000 years service life, supported by the condition of some roman architecture, and user Un Mundo would put his bet on Egyptian concrete. The condition of these buildings can hardly be credibly used as a guide to the service life of modern concrete, however, because those ancient exemplars do not necessarily match the composition of the latter.

In short, the original question remains unanswered. ArthurOgawa (talk) 20:33, 19 November 2014 (UTC)

First, I know nothing more about concrete than the average layman. That said, a couple things seem obvious. 1) "Service life" depends on conditions. A chunk of concrete under my bed will probably hold up better than a chunk of concrete on a seaside dock in Maine. 2) "Service life" depends on design. I've come across many chunks of old concrete that were still quite sound but had been torn up long ago. Apparently some part of the installation had failed even though some of the concrete was in fine shape. It seems to me that "service life" (in a general sense) is not something that can be usefully defined let alone accurately predicted. So, why would we want to try? – JBarta (talk) 23:02, 19 November 2014 (UTC)

A user above has misconstrued my comment on the pyramids as being made of "Egyptian concrete." I do not hold that opinion. It is reliably reported that the pyramids at Giza were constructed from dressed natural stone. My point was, in fact, that these structures of natural stone already have lasted millennia longer than the claimed service life for synthetic concretes.Un Mundo (talk) 22:29, 7 August 2015 (UTC)

References

^ http://www.newscientist.com/article/dn16610-diamond-no-longer-natures-hardest-material.html#.VGv3i4emAwx

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Unintended implcation?

Hi all

It occurred to that this

"In 1889 the first concrete reinforced bridge was built, and the first large concrete dams were built in 1936, Hoover Dam and Grand Coulee Dam."

Might imply that these dams were reinforced. My understanding is that they we not. Comments?

Zoony (talk) 15:23, 2 November 2016 (UTC)Zoony

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Rediscovery

From Anachronism:

A good example of this would be concrete, being used in the past by various ancient cultures only to be forgotten about and then re-invented at a later time by another culture, until the present, at which point the technology is employed globally and unlikely to slip into obscurity again.

Could the history section be more concrete (hehe) about these rediscoveries?

Concrete after a long period of time

What processes take place to concrete after a long extended period of time....please help(i need one paragraph on it)(loic.layne.ll@gmail.com)

Prehistory Nonsense

Apart from being directly copied from the "International Association of Certified Home Inspectors" (not exactly a reliable historical source) the stated Nabataean Empire in 6500BC(!!) directly contradicts the (better sourced) articles about the Nabataean people as well as the Nabataean Kingdom (from 4th century BC) which has the same stated location so I'm guessing it is what the Home Inspectors meant and the 6500BC is a random number fuck up.

Concrete in Construction: Radiation Shielding/Seepage Prevention

What about "heavy concrete" as used for radiation shielding? I am not knowledgeable enough to add this on my own, perhaps it is covered in a type of concrete article. But as for sources, you could start here: https://www.sciencedirect.com/science/article/pii/S0008884602010633 TrentStudent20 (talk) 11:38, 31 May 2018 (UTC)

Useful life section seems to have no useful info

Here is a section that I tried to remove, but I should have explained myself.

===Useful life=== Concrete can be viewed as a form of [[Anthropic rock|artificial sedimentary rock]]. When properly formulated, mixed, placed, and cured it and the compounds it is composed of are extremely stable.<ref>[http://www.msnucleus.org/membership/html/jh/earth/sedimentary/jhsedmentary.pdf Sedimentary Rocks] {{webarchive|url=https://web.archive.org/web/20130511041022/http://www.msnucleus.org/membership/html/jh/earth/sedimentary/jhsedmentary.pdf |date=11 May 2013 }} p. 7, msnucleus.org</ref> Many concrete structures are built with an expected lifetime of approximately 100 years,<ref>[http://enpub.fulton.asu.edu/cement/cbm_CI/CBMI_Separate_Articles/Article%2025.pdf Sustainable Development of Concrete Technology] {{webarchive|url=https://web.archive.org/web/20130514164028/http://enpub.fulton.asu.edu/cement/cbm_CI/CBMI_Separate_Articles/Article%2025.pdf |date=14 May 2013 }}. (PDF) . Retrieved on 2013-02-19.</ref>{{dubious|date=May 2018}} but researchers have suggested that adding [[silica fume]] could extend the useful life of bridges and other concrete uses to as long as 16,000 years.<ref name="eco">[http://www.ecogeek.org/component/content/article/2814 Concrete Structures Could Last 16,000 Years] {{webarchive|url=https://web.archive.org/web/20130113050544/http://www.ecogeek.org/component/content/article/2814|date=13 January 2013}}{{dubious|Cementacious materials are only one part of such [[reinforced concrete]] structures. Rebar will corrode far, far before that.|date=May 2018}}. Ecogeek.org. Retrieved on 2013-02-19. [dead link]</ref> Coatings are also available to protect concrete from damage, and extend the useful life. [[Epoxy]] coatings may be applied only to interior surfaces, though, as they would otherwise trap moisture in the concrete.<ref>[http://www.facilitiesnet.com/groundsmanagement/article/Concrete-Coating-Considerations-To-Extend-Performance-Life--13293 Concrete Coating Considerations To Extend Performance Life] {{webarchive|url=https://web.archive.org/web/20130112145310/http://www.facilitiesnet.com/groundsmanagement/article/Concrete-Coating-Considerations-To-Extend-Performance-Life--13293 |date=12 January 2013 }}. Facilitiesnet.com. Retrieved on 2013-02-19.</ref> A self-healing concrete has been developed that can also last longer than conventional concrete.<ref>[https://www.sciencedaily.com/releases/2010/05/100524143421.htm Self-Healing Concrete: Research Yields Cost-Effective System to Extend Life of Structures] {{webarchive|url=https://web.archive.org/web/20130112001832/https://www.sciencedaily.com/releases/2010/05/100524143421.htm |date=12 January 2013 }} 25 May 2010</ref> Another option is to use [[hydrophobic concrete]]."

Reasoning:

the section does not address the header, i.e. the lifetime of concrete.
statements are disputed, tangential, or supported by narrow, off-topic citations.
it is written poorly

Hence, I propose to remove it, but alternative views are welcome--Smokefoot (talk) 21:15, 21 June 2018 (UTC)

Thanks for taking the time address this material, Smokefoot. Now that I've had time to look it over, I concur that it is poorly sourced, poorly written and dubious. I'll be glad to delete this passage. Cheers, HopsonRoad (talk) 23:44, 21 June 2018 (UTC)

Why were my edits reverted without discussion?

I added fresh references and removed a section of poor tone that was droning on about silicosis. Line and verse about silicosis should go in a silicosis article, if its even in the proper tone.

Explain, please.

Morg00 (talk) 07:53, 9 January 2019 (UTC)

Hi, Morg00. I was the one, who undid your edits with the edit comment, "A series of unexplained edits. Please use the Edit summary, as I'm doing here, for each edit. Better still, please discuss removing so much material in Talk, before commencing the edits! The updated data are not supported by the publicly visible portion of the reference given." Perhaps you are unable to see edit comments with the device from which you are editing. I notice that you reverted my edit without an edit comment, but your explanation here suffices. Sincerely, HopsonRoad (talk) 15:02, 20 January 2019 (UTC)

Nanoconcrete—What is it?

This is to thank User:Vfridman68 for adding details to this section. They may need some more references, if the particulars provided are not explained in the previously existing references. What is missing is verbiage to explain what nanoconcrete is at the beginning of the section. HopsonRoad (talk) 21:31, 8 January 2019 (UTC)

Done I supplied a definition with reference. HopsonRoad (talk) 18:21, 25 January 2019 (UTC)

Split off "History of Concrete"?

This article is huge. Maybe we should split off History of Concrete? As I mentioned in edit notes, the current article refers to Romans > 40x, which seems excessive.--Smokefoot (talk) 21:51, 4 May 2019 (UTC)

Help

~~Help~~

A user is persistently spamming this article and causing those defending it to potentially violate 3RR. Perhaps a block is warranted. HopsonRoad (talk) 13:15, 30 August 2019 (UTC)

1) The 3RR has an exemption for reverting vandalism, and link spamming is a form of vandalism. 2) The user in question just got his final warning, if he does it again I (or whoever else comes along) can report it at WP:AIV. - MrOllie (talk) 13:22, 30 August 2019 (UTC)

Thanks for your post here, MrOllie. In reviewing WP:3RR, it mentions as an exception, "Reverting obvious vandalism—edits that any well-intentioned user would agree constitute vandalism, such as page blanking and adding offensive language." Whereas, Wikipedia:Spam doesn't mention the word "vandal", except in connection with vandalbots. So, perhaps caution is required in reverting spam. Cheers, HopsonRoad (talk) 21:31, 30 August 2019 (UTC)

Yes, but Wikipedia:Vandalism says "Adding or continuing to add spam external links is vandalism if the activity continues after a warning." - MrOllie (talk) 23:03, 30 August 2019 (UTC)

Concrete use by sector

I tried to use the article to figure out what percentage of produced concrete goes to each sector (buildings, roads, etc.) but couldn't find that information. The various types of concrete are broken down, but not how much goes where. Did I miss something? This seems like useful information about concrete. Marshall2389 (talk) 20:22, 26 March 2020 (UTC)

Thank you for your suggestion of how to improve this article, Marshall2389. If you can find some reliable references that explain world-wide usage, we can include it here. Cheers, HopsonRoad (talk) 20:43, 26 March 2020 (UTC)

[1] ttp://www.sustainableconcrete.org.uk/main.asp?page=0

[2] Mahasenan, Natesan (2003). "The Cement Industry and Global Climate Change: Current and Potential Future Cement Industry CO₂ Emissions". Greenhouse Gas Control Technologies - 6th International Conference. Oxford: Pergamon. pp. 995–1000. ISBN 9780080442761. {{cite book}}: |access-date= requires |url= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

[3] EIA - Emissions of Greenhouse Gases in the U.S. 2006-Carbon Dioxide Emissions

[4] The Cement Sustainability Initiative: Progress report, World Business Council for Sustainable Development, published 2002-06-01

[5] Use of carbonic anhydrase in concrete production

[6] ttp://www.newscientist.com/article/dn16610-diamond-no-longer-natures-hardest-material.html#.VGv3i4emAwx

[1]

[2]

[3]

[4]

[1]

[1]

Cracking

Poured concrete, esp. for naval architecture

All concrete poured?

Glasscrete ?

Removed subsection

Discussion pertaining to worldwide useage and practice

Concrete building techniques

Annual concrete production

AfD Nomination: Eco-cement

Length

External links

Water impermeability and porosity

Severe vandalism

Chemistry

Smeaton/Portland cement

Mix Ratios and Yields

What I'm doing

Concrete vs Mortar

Geopolymer green concrete

Missing Header?

Plagiarised content

Errors of Omission

Cement trucks

Merging "Concrete Curing" Article with "Concrete"

Self-repairing concrete

Reactive Powder Concrete

environmental issues

Concrete Shelters

Comment

Concrete failure

Concrete Properties

Self-consolidating concretes - how are they made?

concrete

Problems

Oxygen absorption by concrete in the Biosphere 2 project building

project to be carried out

Pre-roman, Roman and Medieval Concrete

concreat/yard

Neutrality of section "building with concrete"

Melting temperature?

Sources, Images, Advert like

Environmental impact of concrete

Not neutral, many citations needed

electrical properties?

Fire safety niggle

Slump

Disputed neutrality?

History section could be improved by details about widespread adoption

"a complex mixture of not entirely negative effects"

concrete forms/removable forms

Concrete articles

Worldwide CO2 emissions and global change

Carbon Capture and Storage

Bad section

Cement versus concrete

See also list

Section on Cement now duplicates information in that article

Substituted transclusion for File

Types of concrete

Iran develops ultra-high-performance quartz-infused concrete

Fire Safety

Service life

External links modified

Unintended implcation?

External links modified

External links modified

Rediscovery

Concrete after a long period of time

Prehistory Nonsense

Concrete in Construction: Radiation Shielding/Seepage Prevention

Useful life section seems to have no useful info

Why were my edits reverted without discussion?

Nanoconcrete—What is it?

Split off "History of Concrete"?

Help

Concrete use by sector

Worldwide CO₂ emissions and global change