Effect of Super-absorbent Polymer on Hydration and Compressive Strength of Concrete

Super absorbent polymer (SAP) as a kind of internal curing materials can effectively inhibit the autogenous shrinkage and prevent crack formation .However ,it remains to be studied whether SAP has a negative impact on concrete .In this paper ,the hydration products of paste incorporated by different content of SAP were studied by XRD and DTA-TG ,and mechanical properties were tested after standard curing to the different ages .The influence of SAP on hydration and compressive strength of concrete was studied quantificationally .Results indicated that SAP could delay the early hydration on concrete (0—7 d) and the compressive strength of concrete decreased as well .After 7 days curing ,the influence of SAP on hydration and compressive strength of concrete was negligible .When the addition of SAP was 1 kg/m3 (the mass percentage of super absorbent polymer in cementitious material was 0.2％ ) and 1.5 kg/m3 (the mass percentage of super absorbent polymer in cementitious material was 0.3％ ) ,the compressive strength of concrete with SAP was 100％ and 96％ of the concrete without SAP at the age of 28 days .After 56 days curing ,the compressive strength of concrete with SAP was 107％ and 96％ of the concrete without SAP .For C50 concrete ,the recommended content of SAP is 1 kg/m3.