Concrete Ingredients: Cement & Mineral Admixtures
Portland cement (PC) is the principal binder that, upon hydration and setting, holds aggregates (coarse and fine) together in concrete. It has the ability to stand in water and increase its strength over time. This ability elicits the term hydraulic cement for this type of cement.
What is the Composition of PC?
PC is a manufactured product formed within narrow confines of specific elements and subjected to heat treatment to form a semi-finished product called clinker. Raw materials used include: Limestone, Shale, Iron Ore and Sand.
The principal elemental ingredients in the raw materials are:
• Calcium Oxide (CaO)
• Silicon (SiO2)
• Aluminum Oxide (Al2O3)
• Iron Oxide (Fe2O3) in addition to other elemental oxides.
It is possible sometimes to have all these elemental oxides in some limestones. Where the principal source, limestone, is deficient in any of the elemental oxides then the other ingredients are added in the right proportion in preparation for the manufacturing process.
The latter process comprise of three phases:
1. Grinding the materials into a powder form
2. Heating the powdered material in a kiln up to about 2700°F
3. Grinding the clinker formed with gypsum to form PC
When PC is mixed with water either to form a cement paste or concrete, in a process called hydration, a chemical reaction takes place and for simplicity sake two principal products are formed: 1) calcium silicate hydrate, C-S-H and 2) calcium hydroxide
Calcium Silicate Hydrate (C-S-H) is insoluble in water. It gives the title hydraulic to set PC's ability to stand in water without any detriment. Calcium hydroxide is soluble in water and leaches out of set concrete and in a two step approach first, the solution is drawn to the exterior wall of the structure and secondly, react with carbon dioxide of the atmosphere to form chalk, the white, efflorescence salt found on concrete walls.
MINERAL ADMIXTURE - Mineral admixtures used in concrete formulations contain oxides of silica and other oxides that are found in Portland cement. Examples of mineral admixtures include fly ash, silica fume and volcanic ash.
Mineral admixtures used in concrete may be referred to as Pozzolans, or materials that won't harden in water but in the presence of lime, react and harden to form a stone-like mass.
One important use of mineral admixtures in concrete is the ability of the silica component to react with the soluble calcium hydroxide formed in the hydrating cement to form an insoluble calcium silicate hydrate thus helping to form a dense, compact concrete/cement paste.
Concrete formulated with mineral admixtures are not likely to form efflorescence salts. The use of mineral admixtures in concrete helps resist sulfate attack and alkali-silica reactivity. In the fresh concrete the presence of mineral admixtures often improve the workability of the mix.
Related Tags: cement, houston, concrete expert, c3s, concrete consulting, expert witness
Who is C3S, Inc.?
C3S, Inc. is a civil / materials engineering firm, specializing in recommending cement /concrete formulations, petrographic analysis, scanning electron microscopy and other analytical methods to provide an in-depth evaluation of concrete problems. We also provide expert witness testimony. Learn more at: http://www.C3Sinc.com
C3S, Inc. was founded in 1991 by Dr. Ebow Coleman. He is a registered Civil Engineer in Texas (68619). Dr. Coleman was awarded his Doctorate in Civil Engineering from Purdue University in 1981.
His master's studies were completed in Cement Production Technology at the Institute of Chemical Technology in Prague, Czech Republic and B.S. in Chemistry from Kwame Nkrumah University, in Kumasi, Ghana.
Your Article Search Directory : Find in ArticlesRecent articles in this category:
- The No. 1 Rule For Projecting Confidence - Speak With Authority
One of the most important characteristics a person can project in a business setting - or any situat - After the Autumn Checkout European Debt Crisis and U.S. Brewing Rebound
In the commotion caused by the Fed on interest rates come to an end, the "disastrous" for the euro a - Advantages Of Arcade Game Rentals
There are many different advantages to arcade game rentals. Most people need something to release th - A General Primer on Truck Cargo Nets
In modern highways it is quite rare to see truck cargo nets in action, this is because they are usua - The United States Will Burst More Severe Financial Crisis
Not long ago, suddenly announced that the central bank to raise interest rates, the interest rate hi - Niche Marketing Profits - 3 Easy Steps to Finding a Profitable Niche Market Income in 10 Minutes
Like most beginners I was having a very difficult time trying to find a niche market to earn extra m - The Importance of Hospitality Management Consulting Firms Toronto
Businesses and the managers that help guide any business are in a constant state of improvement and - New Keynesian Theory Label
2010 winner of the Nobel Prize in Economics three theories have been labeled as "New Keynesian" labe - Federal Reserve Pouring Money QE2 Unpredictable Fortune
U.S. economist Milton Friedman proposed a "throw the cash from a helicopter" view, while the practic - Fiscal Consolidation Should no Longer Delay
British Chancellor of the Exchequer George Osborne today announced fiscal consolidation policy, shoc
Most viewed articles in this category:
- Common Financial Problems to Avoid
One must first change their habits and not procrastinate. American Consultants Inc at offers key fi - How a Bad Hire Can Hurt Your Business
What's worse - hiring the wrong person or not hiring anyone at all? Companies can become almost des - Joel Comm Is Dr. Adsense
What is Adsense? If you are new to making money online and net marketing, you may not know what Ads - 5 Steps For A Dynamic Wealth System Online
Recipe: Opportunity + knowledge + Dynamic Wealth System + Your Action = Massive Success!!! Step 1 - How To Stop Foreclosure
Losing your house to a foreclosure can be very scary. There are times when circumstances are ou - How to Always Pitch A Strike
As business owners, we are always working on new ways to convince people to become customers, client - Membrane Diffuser Solutions for Wastewater Treatment Systems
In the aeration basin of a typical wastewater treatment plant there are both organic and inorganic m - Another Year Hating Your Job or Loving Life?
Copyright © 2007 Mary Foley I've come to the conclusion that to be successful - really successf - Dyestuff Industry In India And China
World demand for dyes and organic pigments to touch $10.6 billion in 2008According to a study on dye - Cma-cgm Case : the Series of Lawsuits Continues in Syria, Lebanon, Egypt, France, England and the United States
Damietta company case : The series of lawsuits continues in Syria, Lebanon, Egypt, France, England a