Study on compression performance of reinforced concrete columns made using coal gasification ash

The utilisation of coal gasification ash (CGA) is an important way of reducing carbon dioxide emissions in the construction industry. Regarding columns made using coal gasification ash concrete (CGAC), their compressive performance and compatibility with existing bearing capacity formula are undefined, and existing research on concrete columns fails to address differences in their material systems. In this study, three reinforced concrete columns (RCCs) made with ordinary concrete and nine reinforced columns made with CGAC of three strength grades (C30, C40 and C50) and 20% CGA were fabricated to analyse the influences of eccentricity, concrete strength and concrete type on the columns’ failure modes, load–displacement curves, ductility and other properties. The results showed that, compared with RCCs, the CGAC columns exhibited fewer cracks with a more uniform distribution, along with significantly improved bearing capacity and ductility. The compressive performance of the CGAC columns was further enhanced with an increase in concrete strength. With an increasing in eccentric (60 mm–120 mm), the load-bearing capacity decreased while the deformation capacity increased. Based on the test results, the formula for calculating the ultimate bearing capacity was revised, and the revised formula can be applied to calculate the bearing capacity CGAC columns. The influence of factors such as the reinforcement ratio on the load–moment curve was analysed through a parametric analysis.