Expansive Cements and Their Use

The primary purpose of shrinkage-compensating expansive cement concrete is to minimize cracking in concrete pavements and structures caused by drying shrinkage. The paper reviews the various types of expansive cements and their properties. The expansive mechanism and factors affecting it are also reviewed. The physical properties of shrinkage-compensating concrete along with practical considerations such as mixing, placing, finishing, and curing are discussed. Structural design criteria for these concretes are reviewed. Applications involving the use of shrinkage-compensating concretes are suggested. Expansive cement types K, M, and S are available in both shrinkage- compensating and self-stressing grades. The amount of expansive potential a cement has determines its grading and is controlled by the ingredients and formulation of the cement. The effective utilization of this potential is controlled by the cement supplier or user or both. Such features as cement content, aggregate type, mixing times, curing, temperature, and restraint can affect expansion.