ConcreteP3F

Introduction:
 *  [[image:Photo_14.jpg]]

Cement (10-15%) + Aggregate (60-75%) + Water (15-20%) + Air (5-8%) = Concrete
 * Aggregate is a mixture of pieces of crushed stone or gravel **


 * How It Would Be Prepared:**

Regular Concrete is made of sand, crushed stone or aggregates, and cement all mixed with the proper amount of water. A new concrete is being developed to make earthquakes less dangerous. In addition to the regular concrete formula, it is reinforced with stainless steel fibers that can uphold more stress than regular concrete.


 * __Dry Mixture:__**

Portland cement should first be mixed with sand. For sidewalks, driveways and other household uses, a 1:2 ratio of Portland cement to sand is typical. Once the Portland cement and sand are thoroughly mixed, add anywhere from 3 parts to 5 parts gravel. The amount of gravel used should not affect the concrete's tensile strength, but will affect the smoothness of the finished product. The most common ratio of the dry ingredients is 1 part cement, 2 parts sand and 3 parts gravel.


 * __Water:__**

Add water to the dry mixture and mix well until the wet concrete becomes somewhat plastic. Proper plasticity is measured by observing the wet concrete's "slump." To measure slump, fill a conical test mold with well-mixed concrete, remove the mold and measure the amount of height that the concrete cone loses as it spreads. For residential purposes, a slump of approximately 4 inches is appropriate. Fewer slumps creates a stiffer mixture that is harder to work with. A slump of greater than 4 inches may leave the mixture too watery.

__**Concrete Equation:**__

The production of concrete is made from the following equation:

//Geometrical silicate + Water (yields)

Calcium silicate hydrate + Calcium hydroxide + heat

Dicalcium silicate + Water (yields)

Calcium silicate hydrate + Calcium hydroxide + heat//


 * Between .01 and 3%, reinforced fibers such as steel fibers, glass fibers, synthetic fibers, and glass fibers should be added to the mix.


 * Problems with Concrete:**

- needs the right amount of ingredients. - too much water -it can crack -doesn't fry easily


 * Problems with Concrete in Haiti:**

- many building structures were affected - over 30 key buildings were destroyed in Port-au-Prince " To say money, people use bad steel, less cement, and then the concrete, its very technical and complicated (to make), here people aren't able to create good quality concrete," said Patrick Coulombel (Architect).


 * [[image:DSC_0466_resize_21-300x199.jpg caption="DSC_0466_resize_21-300x199.jpg"]] ||

This image shows the damage to concrete buildings in Port-au-Prince, Haiti.

Cost of Concrete per ton.doc

[| http://www.cement.org/basics/concretebasics_concretebasics.asp] [| http://www.cement.org/basics/lessonfiveprint.htm] [| http://nisee.berkeley.edu/lessons/concretemm.html] [| http://composite.about.com/library/PR/1999/b1ncstate1.htm] ** __[| http://www.iitk.ac.in/nicee/EQTips/EQTip17.pdf]__. [| http://www.eqclearinghouse.org/20100112-haiti/photos-by-undp-global/attachment/dsc_0466_resize_2-2 http://www.acehardware.com/product/index.jsp?productId=1308063&kw=cement&origkw=cement&searchId=46498944143]
 * Sources: