Characteristics of plain cement concrete
Plain Cement Concrete or PCC stands for a composite material that is applied for building up different types of civil engineering structures. It is formed by mixing the basic components like cement, fine aggregate (generally sand) and coarse aggregate (generally stone pieces) in desired ratios. Water is added in the necessary quantities and the mixture is arranged into a mechanical mixer to obtain concrete.
PCC with grade M-30, M-40 and M-45 were utilized at the construction site with several design mix.
Properties of cement concrete
Strength of concrete
It should contain high compressive strength. The tensile and shear strengths usually remain 8 to 12% and 8 to 10% of their compressive strength relatively. The compressive strength of concrete is influenced by the following factors :-
- Quality of the material and grading of the aggregates
- Water cement ratio
- Cement content
- Age of the concrete
- Method of mixing, placing, compacting and curing.
Durability of concrete
The concrete comprises of an extreme durability value since it is not significantly affected with climatic action. Conversely, with the age, the concrete gets hardened and as a result, the strength is greatly increased.
Elasticity of concrete
The concrete is not a perfectly elastic material and elastic modulus is influenced by the strength, age and moisture content of the concrete and the type of aggregate utilized. The concrete experiences an extra strain apart from momentary pressure due to a load or stress. This additional strain is known as creep of concrete. It is persistent in character and can’t be recovered on the exclusion of load.
Shrinkage of concrete
The shrinkage occurs because of the following reasons :-
Preliminary shrinkage of cement concrete primarily occurs owing to loss of water through forms and absorption by surface of forms.
The shrinkage of cement concrete happens when it gets solidified. This type of shrinkage on one hand produces cracks in concrete whereas on the other, it holds the reinforcement firmly and makes perfect connection among concrete and reinforcement when utilized in R.C.C. work.
Fire resistance of concrete
Concrete is a good conductor of heat and it has good fire resistance strength because of the existence of pores and water.
Workability is the most subtle properly of concrete. A concrete becomes functional when it is blended easily, managed, transported, arranged in position and compacted. A workable concrete should not demonstrate any segregation or bleeding.