Four-Dimensional X-ray Microtomography Study of Water Movement During Internal Curing

摘要

The goal of internal curing is to maintain saturated conditions within a hydrating cement paste in order to avoid self-desiccation and the accompanying autogenous stresses and strains that may lead to early age cracking. The effectiveness of internal curing, using saturated lightweight aggregates (LWA) or superabsorbent polymers (SAP), for example, has been evaluated based on the measurement of a wide variety of performance properties, including internal relative humidity, autogenous shrinkage, restrained shrinkage and creep, degree of hydration, and compressive strength development. All of these measurements have indicated that the internal reservoirs (SAP or LWA) can be an effective means for supplying the extra curing water needed to compensate for the chemical shrinkage occurring in the cement paste during hydration. Still, it is desirable to make an even more direct observation of the water movement from the internal reservoirs to the surrounding cement paste during hydration.