Confined compressive stress–strain model for rectangular geopolymer reinforced concrete members

Abstract In response to the urgent global challenge of mitigating climate change, sustainable materials have become a focal point across industries, including construction. The construction sector, recognizing its significant contribution to carbon dioxide emissions, has embarked on a relentless pursuit of eco‐friendly practices. Efforts to explore alternatives to cement, notorious for its substantial carbon footprint, have attracted considerable attention. Within this context, the present study delves into an in‐depth analysis of the stress–strain properties exhibited by geopolymer concrete (GC) column members. The primary objective is to develop a comprehensive material model of geopolymer concrete to estimate the flexural capacities of column members. To this end, inspired by the confinement model by Kent and Park, a stress–strain model incorporating the effect of confinement is proposed to accurately estimate the moment capacity of GC columns. The performance of the proposed formulation is checked using 41 different test results obtained from previous research on GC columns. Evaluations on the moment capacity estimations of the proposed model show that the results are promising in reflecting the behavior of geopolymer columns. In addition, moment–curvature curves from six recent experiments are also compared with the moment–curvature curve estimations using the proposed stress–strain model. Results show very close estimations, proving the ability of the model to be a good candidate for the performance‐based design calculations. Besides, the performance of the existing formulations from four prominent international codes (ACI318, BS8110‐97, TS500, and AASHTO) are compared with the proposed model. Notably, the flexural capacity calculated using the code formulations exhibited significant deviations from the experimental results. In contrast, the proposed model demonstrates a strong correlation with the experimental data, substantiating its effectiveness in accurately predicting the flexural capacities of GC columns.