The concrete are classified as follows:
1) plain cement concrete:-the plain cement concrete consists of cement, sand and a coarse aggregate mixed in suitable proportion in addition to water. The cement is used as a binding material, sand as a fine aggregate and shingle, gravel, broken brick or crushed stone as coarse aggregates. The plain cement concrete is strong in taking compressive stress.
2) lime concrete:-the lime concrete consists of lime,a fine aggregate and coarse aggregate mixture in suitable proportions in addition to water. The hydraulic lime is used as a building material, sand surkhi and cinder as a fine aggregates and broken bricks, broken stones as coarse aggregates. The lime concrete is cheaper and has less strength than plain cement concrete.
3) reinforced cement concrete (R.C.C):-the reinforced cement concrete also called ferro- concrete is a cement concrete in which reinforcement is embedded. The rainforced cement concrete is equally strong for taking tensile, compressive and shear stresses.
4) prestressed cement concrete (P.C.C):-the prestressed cement concrete is a cement concrete in which high compressive stresses are artificially induced before its actual use. This type of concrete can take of high tensile and compressive stresses without development of cracks.
5) lightweight concrete:-the lightweight concrete is prepared by using Coke- breeze, cinder or slag as aggregate in the cement concrete. this type of concrete possesses high insulating property. it is used in making precast structural units for partition and wall lining for purposes.
6) cellular or aerated concrete:-the cellular aur aerated concrete also called air entrained concrete is prepared by mixing aluminium in the cement concrete. It is light in weight and spongy in structure. it is used for roof slab and precast units in partition etc for heat and sound insulation.
7) sawdust concrete:-the sawdust concrete is prepared by mixing Portland cement with saw dust in specified proportions in the concrete. it is used as a heat and insulating material.
8) vacuum concrete:-the vacuum concrete is the cement concrete from which entrained air and excess water are removed up with a vacuum pump after placing it in position. The removal of excess air after placing concrete helps in increasing the strength of concrete by 15 to 20 percent. It is used for all reinforced concrete works.
