Updating concrete drying-shrinkage prediction models for local materials

Abstract

This paper addresses the need to update existing concrete drying-shrinkage prediction models to reflect local materials. The experimental program was carried out using eight concrete mixtures of similar strength, manufactured with portland and portland pozzolan cements representing the most used concretes in Chile.

Tests were conducted on 72 specimens and drying strains were measured up to 448 days of drying to investigate the effect of cement type, slump, maximum aggregate size, and specimen dimension on concrete shrinkage. The experimental results were compared with predictions of ACI, CEB, B3, GZ, GL, and Sakata models. All models significantly underestimated the measured shrinkage, particularly for concretes made with cement containing natural pozzolan. Cement type has a significant effect on drying shrinkage time function and magnitude.

A procedure was developed to update existing prediction models. Proposed modifications to CEB relationships were derived to predict shrinkage of concrete made with locally available materials.