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Concrete properties:
setting and hardening

4.1 Strength development
4.1.1 Learning objectives

1 Describe the mechanism of strength development of concrete.
2 Compare the rates of strength development for concretes made with different materials.
3 Describe the effects of sub-normal and of elevated temperatures on the rate of strength

development for different types of concrete.
4 Describe the effects of curing conditions on the rate of strength development of different

concretes.
5 Describe methods for monitoring the rate of strength development of concrete in the

laboratory and on-site.

4.1.2 Background

The strength of concrete is not a precise term describing a property of concrete, but the
ultimate load sustained under defined loading conditions. The strength of concrete has to
be qualified with terms such as tensile strength, flexural strength or compressive strength.
Even then further qualification is needed. For example, with compressive strength, it is
necessary to define the shape of specimen, e.g. 150 mm diameter × 300 mm cylinder,
100 mm cube etc., and if special loading conditions apply, e.g. tri-axial loading. The

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