Thermal movement

The coefficient of thermal expansion of concrete varies between (7 and 14) X 10–6 °C, according to the type of aggregate used, the mix proportions and curing conditions.

Moisture movement

During the curing process, concrete exhibits some irreversible shrinkage which must be accommodated within the construction joints. The extent of the shrinkage is dependent on the restraining effect of the aggregate and is generally larger when smaller or lightweight aggregates are used. High-aggregate content mixes with low workability tend to have small drying shrinkages.

The reversible moisture movement for cured concrete is typically (2–6) X 10–4 °C, depending upon the aggregate.

Creep

Creep is the long-term deformation of concrete under sustained loads . The extent of creep is largely dependent upon the modulus of elasticity of the aggregate. Thus an aggregate with a high modulus of elasticity offers a high restraint to creep. The extent of creep may be several times that of the initial elastic deformation of the concrete under the same applied load. Where rigid cladding is applied to a concrete frame building, compression joints at each storey must be sufficiently wide to take up any deformation due to creep in addition to normal cyclical movements.