PROPERTIES OF CEMENT CONCRETE

Following are the important properties of cement concrete-

(1). Concrete has high compressive strength.

(2). It is free from corrosion and there is no appreciable effect of atmospheric agents on it.

(3). Its hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength. It is the property of cement concrete which gives it a distinct place among the building materials.

(4). It is proved to be more economical than steel. This is due to the fact that sand and pebbles or crushed rock, forming the bulk of cement concrete, to the extent of about 80-90 % are usually available at the moderate cost. The formwork which is of steel or timber can be used over and over again of for other purposes after it is removed. 

(5). It binds rapidly with steel and as it is weak in tension, the steel reinforcement is placed in cement concrete at suitable place to take up the tensile stress. This is termed as the reinforced cement concrete or simply R.C.C.

(6). Under the following two conditions it has tendency to shrink.

• There is initial shrinkage of cement concrete which is mainly due to the lose of water through forms, absorption by surface of forms etc.
• The shrinkage of cement concrete occurs as it hardens. This tendency of cement concrete can be minimized by proper curing of concrete.

(7) It has tendency to be porous. This is due to the presence of voids which are formed during and after its placing. The two precaution necessary to avoid this tendency are as follows:

• There should be proper grading and consolidating of its aggregates.
• The minimum water cement ratio should be adopted.

(8). It forms a hard surface, capable of resisting abrasion.

(9). It should be remembered that apart from other materials, the concrete comes to the site in the form of raw materials only. Its final strength and quality depends entirely on local conditions and persons handling it. However the materials of which concrete is composed may be subjected to rigid specifications.