Concrete enemas что такое
Reddit and its partners use cookies and similar technologies to provide you with a better experience.
By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising.
By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform.
For more information, please see our Cookie Notice and our Privacy Policy .
Get the Reddit app
Memes! A way of describing cultural information being shared. An element of a culture or system of behavior that may be considered to be passed from one individual to another by nongenetic means, especially imitation.
concrete enema
a very beautiful dark skinned girl, who has a good behaviour with a lovely/kind heart/soul rugie is a very lucky name to have, she got the types of smartness, brave, honest, rich and never tell people she’s rich, and she always like testing people and chooses who to be her best friend…. she’s very popular […]
finicking – verb, pest tense: finicked derived from: finicky the behavior of swiping ‘yes’ to or liking everyone on a dating app in order to get matches, then after matching looking at their profile and un-matching immediately after because you’re not interested. a time consuming way to find out who’s liked you on a dating […]
state topper says he didn’t study, but we all know he’s a f-cking sreyans!
yourself and three of your best mates having a 4way and a couple cans, because the footies on. “hey what’s on for the weekend?” “yeah nah, just have a slow roasted local, the swans are playin”
when grab an old lady and put hot sause on your d-ck and f-ck all three holes,before you go in each hole you add another layer of hot sause on your d-ck. frank:d-mn my d-ck from last night. franks friend:what did you do last night. frank:i did the flaming timemachine on this old hoe. franks […]
Disclaimer: concrete enema definition / meaning should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. All content on this website is for informational purposes only.
In concrete
Философский энциклопедический словарь. — М.: Советская энциклопедия . Гл. редакция: Л. Ф. Ильичёв, П. Н. Федосеев, С. М. Ковалёв, В. Г. Панов . 1983 .
Смотреть что такое «In concrete» в других словарях:
Concrete, Washington — Town Welcome sign chainsaw carved from cedar logs greets visitors to Concrete, Washington … Wikipedia
Concrete Industry Management — Genre Concrete industry Founded Middle Tennessee State University (1996 (1996)) Headquarters Murfreesboro, Tennessee, U.S. Number of locations … Wikipedia
Concrete degradation — may have various causes. Concrete can be damaged by fire, aggregate expansion, sea water effects, bacterial corrosion, calcium leaching, physical damage and chemical damage (from carbonation, chlorides, sulfates and distilled water). This process … Wikipedia
CONCRETE — Concrete is a compound made from sand, gravel, and cement, while cement is a mixture of minerals that become hard when water is added, binding the sand and gravel into a solid mass. Although concrete is traditionally considered an Ancient… … Historical Dictionary of Architecture
Concrete ship — Concrete ships are ships built of steel and ferrocement (reinforced concrete) instead of more traditional materials, such as steel or wood. The advantage of ferrocement construction is that materials are cheap and readily available, while the… … Wikipedia
Concrete Marketing — is an independent marketing company based in New York, USA, founded by Bob Chiappardi and Walter O Brien in 1984. is known mainly for its work with cutting edge rock and heavy metal, having amassed a client roster that features bands such as… … Wikipedia
Concrete cover — Concrete cover, in reinforced concrete, is the least distance between the surface of embedded reinforcement and the outer surface of the concrete (ACI 130). The concrete cover depth can be measured with a cover meter. Contents 1 Purpose of… … Wikipedia
Concrete cancer — is a colloquial name for the deterioration of concrete caused by the presence of contaminants or the action of weather combined with atmospheric properties. While often used in the context of the rusting of concrete reinforcement bar (rebar), the … Wikipedia
Concrete and Clay — Single by Unit 4 + 2 B side When I Fall In Love Released February 1965 Format 7 45rpm Genre … Wikipedia
Concrete Blonde — Origin Los Angeles, CA, USA Genres Alternative rock Years active 1982–1995, 2001–2004, 2010 Labels I.R.S … Wikipedia
Concrete (disambiguation) — Concrete is a composite building material made from the combination of aggregate and cement binder. Concrete may also refer to: Reinforced concrete, also called ferroconcrete in some countries, is concrete with embedded reinforcement Literature,… … Wikipedia
Carbonation of concrete
Carbonation of concrete is associated with the corrosion of steel reinforcement and with shrinkage. However, it also increases both the compressive and tensile strength of concrete, so not all of its effects on concrete are bad.
Carbonation is the result of the dissolution of CO2 in the concrete pore fluid and this reacts with calcium from calcium hydroxide and calcium silicate hydrate to form calcite (CaCO3). Aragonite may form in hot conditions.
Within a few hours, or a day or two at most, the surface of fresh concrete will have reacted with CO2 from the air. Gradually, the process penetrates deeper into the concrete at a rate proportional to the square root of time. After a year or so it may typically have reached a depth of perhaps 1 mm for dense concrete of low permeability made with a low water/cement ratio, or up to 5 mm or more for more porous and permeable concrete made using a high water/cement ratio.
Testing for carbonation
The affected depth from the concrete surface can be readily shown by the use of phenolphthalein indicator solution. This is available from chemical suppliers. Phenolphthalein is a white or pale yellow crystalline material. For use as an indicator it is dissolved in a suitable solvent such as isopropyl alcohol (isopropanol) in a 1% solution.
Warning: like all chemicals, phenolphthalein solution should be treated with respect. Both phenolphthalein itself and isopropyl alcohol are harmful and, since it contains alcohol, the indicator solution is flammable. Ingestion, or contact with skin or eyes should be avoided, as should breathing the vapour. Possible effects on the human body include kidney damage and cancer.
For more information do an internet search for something like: «phenolphthalein indicator solution data sheet».
The phenolphthalein indicator solution is applied to a fresh fracture surface of concrete. If the indicator turns purple, the pH is above 8.6. Where the solution remains colorless, the pH of the concrete is below 8.6, suggesting carbonation. A fully-carbonated paste has a pH of about 8.4.
The phenolphthalein indicator solution is applied to a fresh fracture surface of concrete. If the indicator turns purple, the pH is above 8.6. Where the solution remains colorless, the pH of the concrete is below 8.6, suggesting carbonation. A fully-carbonated paste has a pH of about 8.4.
In practice, a pH of 8.6 may only give a faintly discernible slightly pink color. A strong, immediate, color change to purple suggests a pH that is rather higher, perhaps pH 9 or 10.
Normal concrete pore solution is saturated with calcium hydroxide and also contains sodium and potassium hydroxide; the pH is typically 13-14. Concrete with a pore solution of pH 10-12 is less alkaline than sound concrete but would still produce a strong color change with phenolphthalein indicator. It therefore follows that the indicator test is likely to underestimate the depth to which carbonation has occurred.
In confirmation of this, microscopy — either optical microscopy using thin-sections, or scanning electron microscopy using polished sections — shows carbonation effects at greater depths than indicated by phenolphthalein indicator. Nevertheless, this test is very useful as a means of making an initial assessment — it is quick, easy and widely used.
Phenolphthalein indicator solution applied to a fresh fracture surface through a concrete slab.
The indicator has not changed color near the top and bottom surfaces, suggesting that these near-surface regions are carbonated to a depth of at least 4 mm from the top surface and 6 mm from the lower surface. Where the indicator has turned purple — the center of the slab — the pH of the concrete pore fluid remains high (above 8.6, probably nearer 10). Whether the cement paste here is completely uncarbonated is unclear, despite the strong purple indicator color; a more complete assessment would require microscopic examination. Indicator was not applied to the concrete at the right of this image and so the concrete here retains its original color.
The carbonation depth is approximately proportional to the square root of time. For example, if the carbonation depth is 1mm in a one-year-old concrete, it will be about 3mm after 9 years, 5mm after 25 years and 10mm after 100 years.
Get a Better Understanding of Cement
Articles like this one can provide a lot of useful material. However, reading an article or two is not really the best way to get a clear picture of a complex material like cement. To get a more complete and integrated understanding of cement and concrete, do have a look at the Understanding Cement book or ebook.
This easy-to-read and concise book contains much more detail on concrete chemistry and deleterious processes in concrete compared with the website.
For example, it has about two-and-a-half times as much on ASR, one-and-a-half times as much on sulfate attack and nearly three times as much on carbonation. It has sections on alkali-carbonate reaction, frost (freeze-thaw) damage, steel corrosion, leaching and efflorescence on masonry. It also has about four-and-a-half times as much on cement hydration (comparisons based on word count).