Engineering and creep performances of green super-sulfated cement concretes using circulating fluidized bed combustion fly ash

Abstract

This study aims at investigating the engineering and creep properties of a low-energy super-sulfated cement (SSC) concrete with a circulating fluidized bed combustion fly ash denoted as waste anhydrite (WA). The slump, slump flow and setting time tests were used for initially estimating the fresh properties of the SSC concretes. In addition, a comprehensive study on engineering properties of compressive strength, dynamic moduli, ultrasonic pulse velocity, drying shrinkage, and creep was conducted. Experimental results showed that the combination of 25% WA and 5% OPC in mass was the optimal mixture to produce the SSC concretes with the highest 28-day compressive strength of 43.69 MPa and nearly the smallest shrinkage. An increase of OPC tended to reduce the creep of SSC concrete was just opposite to the effects resulting from the WA increase. The microstructural examination clarified that the increment of WA addition resulted in the larger ettringite (AFt) crystals and induced the relatively looser microstructure of binding matrix.