基于DIC的珊瑚粉高强砂浆裂纹演化与强度阈值分析OA

This study aims to develop a low-carbon and cost-effective high-strength mortar(HSM)suitable for island reef construction by partially replacing cement with coral powder(CP)at substitution rates of 0%,5%,10%,15%,20%,and 25%by mass.The mechanical properties of HSM were systematically investigated through uniaxial compression and Brazilian splitting tests,complemented by the digital image correlation(DIC)method.The results indicate that the strength of HSM follows a three-phase evolution pattern of"enhancement,inflection,and deterioration",as the CP content increases.The inflection point occurs at a 5%replacement rate,where the compressive and splitting tensile strengths are recorded at 123.30 and 29.98 MPa,respectively,reflecting increases of 8.6%and 6.2%compared to the control group without CP.When the replacement rate reaches 15%or more,a significant decrease in strength is observed;at a 20%replacement rate,the strength falls below that of the control group.The failure mode transitions from a single brittle fracture(characterized by straight cracks and concentrated strain bands)at lower replacement rates to a combined tension-shear failure(characterized by bifurcation of primary cracks and a dense formation of secondary cracks,with DIC indicating significant localization)at higher replacement rates.To ensure structural safety,toughness,and optimal material efficiency,it is recommended that the CP replacement rate for HSM in island reef construction be maintained between 5%and 10%.