Explicit formulation of drying and autogenous shrinkage of concretes with binary and ternary blends of silica fume and fly ash

Abstract

Shrinkage is generally considered as an important durability property of hardened concrete. During the drying process, free and absorbed water is lost from the concrete. When the drying shrinkage is restrained, cracks can occur depending on the internal stresses in the concrete. The ingress of deleterious materials through these cracks can cause decrease in the compressive strength and the durability of concrete. In the first stage of the study, a prediction model through the most popular soft computing method called neural network (NN) was derived. The data set used for training and testing of the prediction model covers the experimental data presented in the literature. In the second stage of the study, the findings of an experimental study on drying shrinkage behavior of concretes incorporated with silica fume (SF) and fly ash (FA) were reported. Free shrinkage strain measurements as well as corresponding weight loss were measured over 40days of drying. The obtained experimental results were also used for the validation of the proposed prediction models. The highest amount of mineral admixture resulted in high shrinkage strain development. Moreover, the proposed NN model also accurately predicted the values obtained from experimental study.