Experimental study on stress-strain relationship of fiber reinforced lightweight aggregate concrete

An experimental study of nine-group prism specimens with different concrete strength, fiber type and fiber dosage has been carried out to understand the stress-strain relationship of fiber reinforced lightweight aggregate concrete (LWAC) under axial compression load. Failure process and failure characteristics of the specimens were analyzed, and the effect of test variables on the peak stress, peak strain and elastic modulus were studied. Combining with the existing research, calculation formulas of the feature points on test curves were derived. Simultaneously, a segment-based stress-strain model was proposed considering the characteristics of fiber reinforced LWAC. Test results indicate that the failure characteristics of LWAC are significantly different from that of the normal weight concrete. Incorporating fibers into LWAC can effectively restrict the formation of internal micro-cracks, resulting in a prominent crack-resisting and enhancing toughness effect. But these benefits varied slightly with the test variables such as concrete strength, fiber type and fiber dosage. Combining fibers with LWAC can also effectively flatten the decreasing slope of stress-strain curves and improve the brittleness of LWAC. Simulation results obtained from the proposed stress-strain model agree well with the test results, which indicates that this proposed model can accurately describe the axial compressive behavior of fiber reinforced LWAC.