Modulus of Elasticity for Concrete

The typical stress-strain diagram of concrete starts with a linear elastic range, then followed by nonlinearity until the maximum stress.

Such nonlinearity is due to the development of microcracking between the aggregate and cement paste interfaces.

Modulus of elasticity can be measured as the slope of a straight-line portion in diagram, or the tangent to the curve at one point. In any case, it is also known as the tangent modulus.

When we measure the tangent modulus at the origin of the curve, the result is referred to as initial tangent modulus.

Besides that, we can also measure the modulus of elasticity as the slope of the straight line joining two points on the stress-strain curve. In this case, the value is known as the secant modulus.