Plain cement concrete has very low tensile strength. To increase the tensile strength of concrete, a kind of reinforcement is required to take the tensile stresses developed in the structure. The most common type of reinforcement in the form of steel bars was quite strong in tension.
Reinforcement is placed in the form and fresh concrete is poured around it. Cement reinforced concrete is a composite material consisting of concrete and steel reinforcement.
Steel reinforcement, generally in the form of steel bars, placed in the drop zone of the structure and takes tensile stress. Concrete pipes are used for a versatile construction that is strong in compression and tension.
The use of reinforcement in concrete not only increases strength but also helps in preventing shrinkage temperature and voltage.
Action composite steel and concrete
Composite steel and concrete action on the part of the reinforced concrete depends on the following important factors:
(I) The bond between steel and concrete.
(Ii) Prevention of corrosion of reinforcing steel embedded in concrete.
(Iii) Practical same thermal expansion of both concrete and steel.
Use of Concrete
Reinforced concrete cement has innumerable uses in the construction of some listed below:
- water tank
- Road and rail bridge
- Chimneys and Towers
- retaining wall
- Bunker and Silo
Plain Cement Concrete
It is a hardened mass obtained from a mixture of sand, cement, gravel and water in definite proportions. These materials are mixed together to form a plastic mass that is poured into the mould to the desired shape called a form.
This hardens the plastic mass in the setting and we get a plain cement concrete. Hardening of the mixture is caused by a chemical reaction between cement and water.
Plain cement concrete has good compressive strength but very little tensile strength, thus limiting their use in construction. plain concrete used where good compressive strength and weight are major requirements and very low tensile stress.