Study on the eccentric compression performance of coal gasification ash concrete columns

To promote the utilisation of coal gasification ash (CGA), the influence of replacing cement with CGA on the compressive performance of concrete columns was investigated. A total of eight reinforced concrete columns – two ordinary concrete (OC) columns and six CGA concrete (CGAC) columns – were fabricated to evaluate the influence of CGA, eccentricity and concrete strength on damage patterns, load–deflection curves, crack development and so on. The results showed that the CGAC columns and OC columns had similar failure modes, but the CGAC columns had better mechanical properties. The ultimate eccentric bearing capacity of C40 grade CGAC columns was 12.3–15.7% higher than that of OC columns of the same strength, and the ductility coefficient was 9.8–13.2% higher. When the eccentricity was small, the load-bearing capacity increased by 8.5–10.2%. The peak load simulation error of the finite-element model was 1.2–5.0%, meaning that the mechanical response was accurately reproduced. Parameter analysis showed that when the reinforcement ratio was increased from 1.13% to 2.01%, the small eccentric bearing capacity of the CGAC columns increased by 13.7% and the large eccentric bearing capacity increased by 46.3%. In addition, the incorporation of CGA in concrete can significantly reduce carbon dioxide emissions and lower costs.