ASR expansion, expansive pressure and cracking in concrete prisms under various degrees of restraint

The objective of this study is to reveal the characteristics of expansive pressure, the longitudinal and the transversal expansion and cracking in concrete prisms (100 × 100 × 400 mm) under various degrees of uniaxial restraint. Relationships between expansive pressure and the degree of restraint in concretes with various alkali contents were nearly linear in the range of low degree of restraint. Increase rates in expansive pressure with the degree of restraint were drastically reduced above a critical degree of restraint. Expansions were promoted in a direction perpendicular to the restraining direction. After the release of restraint, concrete prisms continued to expand for several months, and ultimate expansions in the transversal direction were greater than those in the longitudinal direction. Surface cracks in concrete prisms under restraint oriented toward the direction of restraint. Some of internal cracks came out on surfaces in the concrete prisms.