Self-Compacting Concretes with Supplementary Cementitious Materials: Shrinkage and Cracking Tendency

Abstract

This paper aims to contribute to the characterization and the understanding of shrinkage and cracking tendency of self-compacting concretes (SCCs) where portland cement (CEM I) is partially substituted by supplementary cementitious materials (SCMs). The free shrinkage from casting to 400 days of aging of four SCCs mixtures based on CEM I 52.5 N, CEM III/A 52.5 L containing 62% slag addition, CEM V 42.5 N containing 20% fly ash and 25% slag additions, and CEM I 52.5 N+15% of metakaolin (MK) is investigated. The development of cracks due to a restrained shrinkage is studied using ring tests. Nonevaporable and evaporable water contents, setting times, and compressive and splitting strength are measured. Results show that compared to portland cement SCC, SCCs with SCMs are more sensitive to drying shrinkage at very early ages. However, at long term, they exhibit different behaviors. SCC with 15% MK presents the best properties, with a significantly low drying shrinkage and a high compressive strength at 28 days and beyond. SCC with CEM III cement presents the highest compressive strength at 28 days onward but also the highest drying shrinkage at long term. In restrained conditions, SCCs with SCMs are more sensitive to early cracking. However, their crack opening is at least 1.57 times lower than the one of the reference SCC, which presents an important advantage for durability considerations.