Influence of superabsorbent polymer on shrinkage properties of reactive powder concrete blended with granulated blast furnace slag

This study involved investigating the contributions of granulated blast furnace slag (GBFS) and internal curing (IC) by means of superabsorbent polymer (SAP) on shrinkage behaviour, hydration heat, and mechanical strength of reactive powder concrete (RPC). The results indicated that autogenous shrinkage decreased with an increase in GBFS content, and a combination with IC completely mitigated autogenous shrinkage and even led to a net expansion. The mechanical strength decreased with the addition of GBFS. However, compressive strength still exceeded 100 MPa even when the replacement level of GBFS corresponded to a maximum of 50%. Although IC by means of SAP slightly reduced the strength, this reduction was acceptable given the important role that it played on mitigating autogenous shrinkage. The drying shrinkage and mass loss increased significantly with an increase in the GBFS content. The IC did not exhibit an obvious effect on drying shrinkage and mass loss. However, it counteracted high drying shrinkage by significantly reducing autogenous shrinkage. The total shrinkage of RPC with IC and GBFS was significantly lower than that without IC and GBFS. The combination of GBFS and IC can adequately solve serious shrinkage deformation and provide an environmental friendly and low cost method to produce RPC.