The cement concrete is developed by blending a mixture of cement, sand, pebbles or crushed rock and water. It turns out to be rigid when positioned in the frame of forms and started to cure. The concrete is considered as a primary building material in all segments of modern construction due to the reasons given below :
1. It is instantly moulded into long-lasting structural items having different sizes and shapes without incurring any labor charges.
2. The properties of cement concrete within an extensive range can be easily managed with the use of proper components as well as various special processing methods like mechanical, chemical and physical. 3. The planning and placing methods are fully automated. 4. It retains sufficient plasticity for the mechanical working.
Properties of Concrete: The cement concrete consists of the following crucial properties -
1. It contains a great compressive strength. 2. It withstands corrosion and free from any effect caused by atmospheric agents.
3. It solidifies in due course of time and the solidification carries on prolonged period once the concrete has got enough strength. 4. It is more economical as compared to steel as itís main ingredients like sand and pebbles or crushed rock are generally obtained at reasonable cost. The formwork that is made of steel or timber, can be applied repeatedly or for other purposes once it is eliminated. 5. It is instantly attached with steel and beasuce it is feeble in tension, the steel reinforcement is arranged in cement concrete at appropriate places to bear the tensile stresses. This is called the Reinforced Cement Concrete or simply R.C.C.
6. It is inclined to be shrinked under two conditions. The early shrinkage of concrete may occur because of the loss of water over forms, absorption by surfaces of forms etc. The cement shrinkage may also happen once it is solidified. This tendency can be reduced with appropriate curing of concrete.
7. It has inclination to be absorbent because of the existence of voids which are developed during and after its placement. But, if perfect grading and compilation of the aggregates is done, the problem can be resolved. Besides, minimum water-cement ration must be implemented to prevent such voids. 8. It develops a rigid surface that can prevent abrasion. 9. Concrete arrives to the site in the form of raw materials only. Its final strength and quality are entirely based on local conditions and persons dealing with it.