Modeling the drying shrinkage of structural concretes

Abstract

Shrinkage in hydraulic materials is a complex time-dependent process. For standard concretes, one of the most considerable parts of shrinkage is drying shrinkage. In fact, to predict deformations of concrete due to shrinkage, various predictive models have been developed; most of them use many numbers of factors that can affect shrinkage such as concrete strength, concrete age of loading, curing conditions type, ambient conditions, type of cement and aggregates, water to cement ratio, concrete mix, member shape and size, loading duration and type. Such a number of parameters increases the complexity of using these models and leads to some prediction imperfections; thence a new simplified model is needed. The main target of the current paper is to formulate a novel and simplified model with a minimum of factors that affect drying shrinkage behavior as relative humidity and volume to surface area ratio of the concrete element (V/S). To achieve this goal, a prediction model based on probability density function and a small number of parameters that influence shrinkage, as well as relative humidity and volume to surface area ratio of the concrete element, has been developed. A huge database has been used to adjust the model's parameters using the most recent studies and research to validate the model. The comparison of the model predictions with experimental results reveals that the simplified model is well adapted to represent and describe the evolution of drying shrinkage for normal, high-performance, lightweight, and self-compaction concretes, whereas there is negligible prediction divergence as compared to other existed models.