Shrinkage and Creep of Concrete

Structural engineers are concerned with the consequences of shrinkage, creep and cracking on the serviceability and durability of their structures. Creep increases deflections, reduces prestress in prestressed concrete elements, and causes redistribution of internal force resultants in redundant structures. Shrinkage can cause warping of slabs on grade due to differential drying and increased deflections of non-symmetrically reinforced concrete elements. Materials scientists are concerned with understanding the basic phenomena and assessing new materials and the effects of admixtures on the mechanical behavior of concrete.

Concrete is an age stiffening material that has little tensile strength, shrinks, and exhibits creep in sealed conditions and additional creep in drying environments. Predicting the amount of shrinkage and deflection that may occur is not easy and is especially complicated in concrete that contains supplementary materials, chemical admixtures, and lightweight aggregates. Supplementary cementing materials and waste products are being used in increasing volumes in response to environmental concerns. Admixtures have been developed to modify the behavior of fresh and hardened concrete. Self consolidating concrete is being used in more applications. A recent development is the marketing of shrinkage reducing admixtures.

This volume contains papers that cover many aspects of shrinkage and creep. Special attention is paid to the development, use, and evaluation of models to predict shrinkage, creep, and deflection, while other papers consider the behavior of early-age concretes that are restrained from shrinking. Additional highlights include a field assessment of creep and shrinkage in concrete structures, early-age tensile stress development, and experimental results to quantify differential drying and thermal deflections in slabs.