Abstract
This study reports the results of a series of experiments, particularly paying attention to the early-age behavior and response of hardening mortars incorporating different types and contents of superabsorbent polymer (SAP) under autogenous (sealed) and drying shrinkage (unsealed) conditions. To achieve this primary aim, the effects of SAP type (i.e., cross-linking density and grain size) and content on the internal relative humidity (IRH) changes and corresponding free shrinkage behavior, restrained stress development, and cracking potential of the mortar were extensively measured and analyzed, along with their strength and set time properties. The results of this study have shown that the internal curing (IC) via SAP effectively counteracted the early-age residual stress build-up due to autogenous shrinkage, as many other former studies described. No or little tensile residual stresses due to autogenous shrinkage took place when more than 0.4% SAP was added, regardless of the SAP type. However, it should be mentioned that the addition of SAP, irrespective of its content and type, hardly improved the shrinkage cracking resistance of the mortar when directly exposed to drying environment at early ages.
Highlights
IntroductionUltra-high-performance concrete (UHPC) mixtures are required to meet specific performance criteria such as 28-day compressive strength of
This is presumably because as the cross-linking density increases, a higher level of retraction forces acts in the network structure, which empties the entrained water in superabsorbent polymer (SAP) faster, and in turn raise the degree of hydration of cement [41,49]
Internal relative humidity (IRH), autogenous shrinkage, restrained shrinkage stress development, and cracking potential were measured for the evaluations
Summary
Ultra-high-performance concrete (UHPC) mixtures are required to meet specific performance criteria such as 28-day compressive strength of
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