Early-age and Long-term Strength Development of High-performance Concrete with SAP

Abstract

Internal curing of high-performance concrete (HPC) by the addition of Superabsorbent Polymers (SAP) has been proven to be effective in mitigating autogenous shrinkage. The issues of concern in research, however, is the extent to which strength development is impacted by the voids created by SAP as cement hydrates with age. In this study, the influence of SAP contents, size, binder type, water/binder ratio (W/B) and curing age on the early-age and long term strength development of a low W/B HPC was examined. HPC mixtures designed for 28-day target cube strength of 70 MPa minimum (i.e. C55/67 – C100/115), were studied with 25 g/g extra water provided for SAP absorption. Mortar (50 mm) and concrete (100 mm) cubes were cast and cured in water for different hydration periods. The results reveal that the compressive strength of the HPC mixtures decreased slightly (both for the early-age and long-term) as SAP contents increased. Statistical examination of the results further revealed that W/B and SAP contents significantly influenced the strength development while a simulation of the SAP’s water absorption into Powers’ Model show compatibility for prediction of strength development trends in HPC with SAP