Plastic Shrinkage Cracking in Internally Cured Mixtures Made with Pre-wetted Lightweight Aggregate | NIST

Abstract

The incorporation of pre-wetted lightweight aggregates (LWA) has been used to reduce the shrinkage cracking associated with self-desiccation in the hardened state. Little research, however, exists to show the influence of internal curing on the formation of plastic shrinkage cracks. The paper presents a background on the formation of plastic shrinkage cracks and then presents results from a study that examined mortar and concrete systems with pre-wetted LWA. Specifically, the results indicate that the incorporation of pre-wetted LWA can reduce settlement and formation of plastic shrinkage cracks. It is shown that water will preferentially leave the LWA during early-age drying, thus resulting in a system where the cement paste remains more saturated.