Predictive theoretical model for elastic modulus of marine geopolymer concrete: Insights into micro-mesoscopic components and alkaline content effects

Abstract

Marine geopolymer concrete, recognized for its low-carbon and highly durable properties, garnered considerable attention in ocean engineering applications. Given the lengthy testing and numerous variables in concrete research, developing a theoretical model with clear physical meaning to capture the effects of micro-mesoscopic components and alkaline content on the elastic modulus was essential. Based on multi-scale techniques, this study introduced a three-step homogenization framework to consider the impact of proportion for pores with different sizes on the elastic modulus of the concrete matrix. Then, a single-aggregate concrete was established using a two-phase spherical system, followed by a model incorporating both coral coarse aggregate and normal limestone aggregate via the Effective Medium Approximation. A damage factor was included to account for internal curing effects and matrix shrinkage-induced damage. Seven groups of concrete specimens with different coral coarse aggregate and alkaline contents were tested to validate the accuracy of the model. The model was then employed to thoroughly analyze the effects of total aggregate content, aggregate elastic modulus, aggregate volume fraction, sand ratio, total porosity, effective pore proportion, and alkaline content on concrete’s elastic modulus. The optimal design suggested a coral coarse aggregate volume fraction of 50% and an alkaline content of 5%.