Experimental study on strength and carbonation performance of hybrid fibre lightweight aggregate concrete in precast structures

Abstract

Abstract To improve the brittle failure characteristics and carbonation performance of lightweight aggregate concrete, basalt fibre, and polyacrylonitrile fibre were incorporated. The effects of the two fibres on the compression strength and carbonation depth were studied through compression tests and rapid carbonation tests. The effects of mineral admixture proportion were also studied. The results show that when the mass content of basalt fibre and polyacrylonitrile fibre is 2.8 kg/m3 and 0.9 kg/m3, respectively, the average increase of compression strength for different ages is approximately 40%, and the average decrease of carbonation depth for different ages is approximately 8%. Furthermore, when the mass content of mineral admixture is 30%, the higher proportion of slag contributed to the greater compression strength, but smaller carbonation depth. As supported by the experimental results, the improvements in strength and carbonation performance of lightweight aggregate concrete will make it more competitive in the application of precast buildings and long-span bridges.