Strategies for improving dimensional stability of concrete

Changes in dimension of concrete due to early-age heat generation, long-term drying shrinkage, and creep under sustained load could lead to significant movements of the concrete structure and lock-up stresses if the movements are restrained. The lock-up stresses are often large enough to cause cracking and water leakage, thereby adversely affecting the serviceability and durability of the structure. Whilst the dimensional changes are quite variable because of their dependence on the environmental conditions and applied loads, they are all related to the concrete mix proportions. Generally, the dimensional stability of concrete can be improved by reducing its cement content and paste volume. Moreover, since the aggregate also shrinks, the dimensional stability can be improved by suppressing the shrinkage of aggregate as well. In this paper, strategies for improving the dimensional stability of concrete are formulated based on experimental research. Test results are presented to demonstrate their effectiveness and applicability.