Question

This question refer to Reinforced Concrete Design

1a) Illustrate the relationship between concrete strength and curing time.

b) How does the code simplify the nonlinear compressive concrete stress distribution?
Illustrate

Answer 1

1a) Strength of concrete increases with increase in curing time.

The important time for concrete to gain strength is as soon it placed.

If water is immerse in water, its strength will increase rapidly in earlier stage and rate of increase will reduce at later stage, but strength will still increase if the concrete is under the contact of water.

if concrete is not immerse in water then less strength will increase at earlier stage and no strength will develop at later stage.

when cement is mixed with water, heat of hydration is liberated and concrete starts gaining its strength, excessive liberation of heat can damage concrete and lower its strength, then water is used for controlling heat to attain maximum strength.

Due to lack of water, heat of hydration will not be absorb and concrete will shrink. which will increase tensile stress in concrete. which lead to development of cracks on concrete and concrete will attain less strength.