RCC first class 15.01.2020

PCC: 

PCC consist of Cement, Coarse Aggregate, Fine Aggregate and Water.
PCC strong in compression & weak in Tension.
Compressive Strength is 10 time higher than Tensile Strength.
Mass Structure.

RCC: 

It is a concrete which steel is embedded in it. There fore it also becomes strong in Tension and Ductility is also.
In Flixer member like beam and slab portion comes under Tension in which steel is embedded.
It is assumed that the bond between steel &concrete is strong enough to have strain compatibility.
Concrete is brittle materials where steel is ductile in Nature.
The ductility of steel leads to large deflections in RCC structures giving couple warning failure.
Tensile stress will be due bending, Temperature, Shrinkage etc.

Compressive strength of Concrete[IS 456(2000)]

As concrete is strong in Compression, Compressive strength is the most important property of concrete. The other properties like Tensile strength, Modulus of Structure, short term modulus of Elasticity, long term modulus of Elasticity will be determine Compressive strength by formula code IS456.

Determination the compressive strength of Concrete

Cube Test:

In cube test 3 samples are taken of a given concrete. The size of 150 mm. Average value of this sample will give the compressive strength of the concrete.
Strength valued every sample will be average (+-)150%.

Characteristic of compressive strength of concrete

Definition: C.S is that Strength of Concrete that 95% sample will have more strength than it or the strength of concrete bellow which not more than 5% of test results are expected to form.

PROBLEMS:

1. The compressive of standard 15cm cu are given bellow.
Determine the characteristics & compressive strength of concrete.
28 MPa, 33 MPa, 30 MPa, 18 MPa, 40 MPa.

2. Calculate long term elasticity of concrete as per IS456. Grade of Concrete is given as M25. Creep co-efficient 1.5.
So calculate the value.