Concrete is the backbone of civil engineers. Mostly we use concrete as a construction material because of its own stand out efficiencies. There are different types of special concrete which we use for special purposes :
A monomer is an organic molecule which is capable of combining chemically with similar or different molecules to form a high molecular-weight material, known as polymer. A polymer consists of numerous monomers which links together in a chain-like structure, and the chemical process which causes these linkages is call as polymerization.
There are three types of polymer-concrete composites:
Polymer impregnated concrete (PIC), Polymer concrete (PC), Polymer portland cement concrete (PPCC)
It acts as a coupling agent, and the interfacial bond between polymer and aggregate and, therefore, we can improve the strength of the composite.
Sulphur- concrete composites
In this type of concrete, we have to add sulphur, and fine aggregates and coarse aggregate, but contains no water or cement. In this type of concrete we have to maintain a high temperature (140 o C) during mixing, this ingredients forms a uniform mix which can be cast into moulds. The mix proportion for optimum strength and workability are typically obtain using 32 % sulphur, 48 % coarse aggregate and 5 % silica flour. This type of concrete attains strength very rapidly.
Fibre reinforced special concrete
In cases where we require high tensile strength concrete we tend to add fibre in the cement based matrix. It also delays the crack formation and thus helps in increasing the toughness. The quantity of fibre used should be less than 5 % to give the most efficient result.
This is also a type of reinforced cement concrete. In this type of concrete closely spaced, multiple layers of mesh or fine rods are used as reinforcement. In structures where there is a limitation of thickness and situation when we don’t recommend to use reinforcing bar as it will occupy more space.
Very high strength special concrete
Present scenario demands for high strength concrete (upto 100 MPa). We can consider high strength concrete from 60 MPa – 100 MPa. Advantages of using a high strength concrete is that a lesser size sections can be used and thus can be economically . We can introduce suitable admixtures so as to increase the strength of concrete.