An Experimental Study of Autogenous and Drying Shrinkage

Abstract

Shrinkage of concrete is the time-dependent strain in an unloaded and unrestrained specimen at constant temperature. It is usually considered to be the sum of drying shrinkage and autogenous shrinkage. Drying shrinkage is the reduction in volume caused principally by the loss of water during the drying process and this continues perhaps for years after the concrete is cast. Autogenous shrinkage results in the main from various chemical reactions within the cement paste and occurs in the first days and weeks after casting. All else being equal, drying shrinkage increases with an increase in the water to binder ratio and autogenous shrinkage decreases. For higher strength concrete, autogenous shrinkage is significant and must be considered in the design of concrete structures for serviceability.