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History of Concrete and Its Ingredients
In order to understand the history of concrete we must first understand what concrete is and what it is made up of. Concrete is a construction material composed of cement, coarse aggregate, sand, and water. The chemical process known as hydration solidifies concrete after it is placed making it into a very versatile and durable construction material. Cement the main ingredient in concrete is chemically made up of Calcium, Silicon, Aluminum, and Iron. Common materials used in making cement are Limestone, Sand and Clay which contain all the chemicals necessary in making cement. Cement is made by taking Limestone from a quarry and trucking it to a cement plant where it is crushed to marble sized pebbles. It is then ran through a blender where it is mixed with sand and clay, then it is all ground into a powder and sent into an extremely hot rotating furnace in a process known as sintering. The raw materials reach 2700 Degrees F and this causes chemical and physical changes to the raw material and it comes out of the furnace as clinker or large glassy red hot cinder that are then ground to a fine gray powder, it is now Portland Cement the main component in modern concrete.
Concrete was first invented by the Roman in 1243 add It is not known exactly in what form or ingredients made up Roman Cement; however the Assyrians and Babylonians used clay as the bonding agent or cement in their concrete. In 1756 British engineer John Smeaton invented what we know today as modern concrete. Smeatons concrete was made up of small pebbles as aggregate and powered brick as the cement admixture. In 1824 English Inventor Joseph Aspdin invented Portland cement which has remained the dominant cement used in modern day concrete production. Concrete has been around since the Roman Empire although not in its same form the concept has been around since the dawn of modern civilization. It has proven itself to be a reliable and versatile construction material and when reinforced is nearly indestructible. The United States boasts a $35 billion dollar a year concrete industry employing some two million workers in the United States alone. Not only is concrete a solid building material but it has also helped build our economy and continues to grow. Concrete will be a huge part of the construction industry for years and years to come.
Posted by Owner July 5th 2011
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How to configure concrete volume
One of the first steps in figuring out how much concrete is needed in a standard driveway is to define “standard”. Concrete is measured in cubic yards and to have an accurate amount of concrete requires you to know precisely how many square feet of surface area you are covering as well as the depth desired. So for the sake of this article we will say a standard two car driveway is 20’x20’ or 400 square feet. Typically unless requested to be thicker by the homeowner contractors pour driveways 4” thick. So for figuring concrete in this example we would take the square footage and multiply it by the decimal percentage of 4”/12” to get our cubic footage and then transfer it to cubic yards. So 400 x .33 = 132 cubic feet. Now we want to convert our cubic feet into cubic yards so we know what to order from the plant. There are 27 cubic feet in one cubic yard so we would take 132 and divide by 27 giving us 4.89 cubic yards needed. Now we know we need 5 yards to do the job but in this example five yards is barely enough so it is recommended to order one more yard to be safe. So for a standard 20’ x 20’ two car driveway we would need 6 yards to do the job and not run out of concrete. Figuring how much concrete is needed is only half the battle, concrete used in driveways must be reinforced and also contain the right mixture of Portland cement to hold up to the demands expected of it as a driveway. Concrete is a very versatile building material that will generate years of maintenance free service as long as it is place correctly and reinforced. Concrete has enormous compressive strength but little to no tensile strength, making it a good material to drive on but it must be reinforced with steel to keep from cracking and coming apart. So in the industry it is standard for a five sack mix or 3000 psi mixture with 3/8” or #3 rebar to be placed on 18” centers both ways ensuring that the rebar is exactly in the middle of the concrete to be effective. So figuring concrete and rebar for any project is just as easy, remember to figure square footage first then multiply by the decimal percentage of how thick you require it to be and divide by 27. Now you know how to effectively figure yards of concrete for your next project.
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