Experimental study on the mechanical properties of internally cured concrete with super absorbent polymer under monotonic and cyclic loads

Abstract

Four-point bending tests were carried out on super absorbent polymer concrete (SAPC) specimens under monotonic and cyclic loads to investigate the mechanical behavior of internally cured concrete with SAP agent. Firstly, the failure mode of SAPC under static four-points bending load was presented. Secondly, the load–displacement curves, as well as the tensile stress–strain curves of the concrete specimens, were obtained. The variation laws of critical parameters were fitted and analyzed by examining the characteristic values of stress–strain curves under monotonic loadings. The mathematical models were proposed based on the experimental results. Thirdly, the relationships between the plastic strain, unloading strain, and reloading strain, together with the damage index of concrete, were studied extensively, referencing the results of cyclic loadings. The stress–strain models of SAPC during cyclic loading were established, incorporating the damage index under different SAP contents. A comparison of the proposed model with the test data demonstrated satisfactory agreement. In conclusion, the results reveal basic characteristics of SAPC after the full curing period and present fundamental mechanical properties of SAPC under monotonic and cyclic loadings. The study provides valuable references for improving the application of SAPC in engineering practices.