Effect of recycled coarse aggregate on the tensile stress–strain curve of seawater sea-sand concrete

The utilization of recycled coarse aggregate (RCA) in seawater sea-sand recycled aggregate concrete (SSRAC) offers notable environmental advantages for marine engineering applications. This study systematically investigated the complete stress–strain behavior of SSRAC under uniaxial tension, with a focus on the influence of the RCA replacement ratio, curing age, and curing environment. The findings indicated that the use of seawater and sea-sand enhanced the tensile performance of recycled aggregate concrete. Both the peak tensile stress and the elastic modulus of SSRAC were observed to decrease gradually as the RCA replacement ratio increased. Under seawater immersion conditions, sulfate ion erosion initially improved the tensile properties; however, with prolonged exposure, a degradation trend emerged, leading to a subsequent decline in tensile performance. Based on the experimental results, a predictive model for the uniaxial tensile stress–strain curve of SSRAC was developed, incorporating the RCA replacement ratio as a key parameter.