Effect of rebar self-stress on behavior of autoclaved aerated simply supported R/C thin beams subject to uniform transverse dead load

Abstract

Autoclaved aerated concrete (AAC) beams typically incur counter-arch deflection with stored stress induced by the high-temperature and pressure steam curing. This study investigates the effects of the resulting self-stress on the flexural performance of steel rebar reinforced AAC beams. Accordingly, a simplified experimental model was designed to decouple the bar self-stress from other load mechanisms that exist in full-scale structures. Surcharge loading was applied, and the self-stress of steel rebar was measured by the releasing method. The cracking pattern of the AAC test beams and the associated load-deflection curves were analyzed. The values of self-stress in different locations of the beam were obtained, and the influence of steel bar self-stress on the cracking load was calculated. The test results show that the cracking moment resisted by the self-stress accounted for 65.7% of the theoretical cracking moment. Numerical simulation results confirmed that asymmetric reinforced AAC beams incur a counter-arch phenomenon, and further quantified the corresponding effect of self-stress on the cracking load. Therefore, accurately accounting for the rebar self-stress can more accurately define the cracking load capacity of AAC beams and should be considered in design, which should make AAC beams a stronger contender in diverse field applications.