Flexural behavior of alkali-activated slag-based concrete beams

Limited study has been performed on the application of alkali-activated concrete to structural members. The present study investigated the flexural behavior of performance-based alkali-activated slag-fly ash concrete beams. Four-point static bending tests were performed on twelve alkali-activated concrete (AAC) beams and three ordinary Portland cement concrete (PCC) beams, in order to investigate the effects of concrete strength, rebar ratio, and beam depth on the flexural performance. The structural performance was evaluated, including the moment-curvature relationship, flexural stiffness, load-carrying capacity, ductility, rebar strain, crack distribution, and failure mode. The test results showed that the flexural behavior of AAC beams was comparable to that of PCC beams. The increase of the beam depth significantly improved the flexural stiffness and load-carrying capacity of AAC beams. As the rebar ratio increased, the load-carrying capacity increased significantly, but the ductility decreased. The concrete strength did not affect the flexural performance of AAC beams. The current design code safely predicted the effective flexural stiffness at service condition and the load-carrying capacity. Thus, the current design code is applicable to the design of AAC beams showing flexural behavior.