Internal curing uses pre-wetted fine lightweight aggregate (LWA) to supply cementitious systems with water. This increases the hydration of cement and reduces the influence of self-desiccation resulting in concrete with increased compressive strength, reduced permeability, and reduced shrinkage potential (Shah et al., 1998; Henkensiefken et al., 2009; Henkensiefken et al., 2009). While these mixtures have shown great potential, there has been considerable debate on how internally cured samples should be conditioned during laboratory testing. This paper explores the influence of sample storage and curing on the properties of mixtures prepared with and without internal curing. Samples were prepared and cured in environments that supplied additional moisture, were moisture neutral, or allowed moisture loss. Experimental results show that when adequate external curing water is supplied, only limited benefits are seen from internal curing. The benefits of internal curing are more evident in systems that do not receive additional external curing water (sealed) and even more so when systems are exposed to external drying. These conditions are likely more representative of what may be experienced in typical field applications.
Citation: Journal of ASTM International
Pub Type: Journals
Curing, elastic modulus, hydration, internal curing, lightweight aggregate, strength.