Influence of cracking on the capillary absorption and carbonation of structural lightweight aggregate concrete

Abstract

This paper aims to study the influence of the presence of cracks on the capillary absorption and carbonation resistance of structural lightweight aggregate concrete (LWAC) and to compare its behaviour to normal weight concrete. For this purpose, the effect of artificial and natural cracks on LWAC with different w/c and types of aggregates was analysed. Artificial and natural cracks in the range 0.1–0.3 mm were induced by the notch method and bending tests, respectively. Results show that the influence of artificial cracks on the studied durability properties was not significantly affected by the aggregate type. However, when LWAC was subjected to natural cracks, there was greater participation of the more porous aggregates. For crack widths greater than 0.1 mm, the resistance to CO2 diffusion was less affected by the crack characteristics. Depending on the relationship between carbonation depth and crack length, the estimated carbonation rate under real exposure conditions can increase more than 80% in cracked concrete.