In support of sustainable development strategies, engineering construction on remote islands is conductive to promoting the development of marine resources and mitigating increasingly severe resource conflicts. However, marine engineering, facing extreme weather and natural disasters, necessitates concrete with high ductility, durability and crack control capacity. This study evaluates the feasibility of using seawater and coral sand instead of fresh water and river sand to prepare the high ductility cementitious composites (SCS-HDCC). The results indicate that increased coral sand substitution introduces defects and expands the aggregate-matrix interfacial zone due to its rough surface, high specific area, and low strength. Coral sand's internal curing enhances compactness and reduces harmful pores. The dual action of seawater and coral sand, SCS-HDCC matrix is more tenacious, and the damage and blockage during the fiber pull-out process becomes obvious, and the slip hardening coefficient of fiber-matrix interfacial zone increases. SCS-HDCC achieves satisfactory ductility (up to 1.18 %) with initial cracking strength of 4.18 MPa, ultimate tensile strength of 5.66 MPa, and crack width of 71.2 ± 6.74 μm, average crack spacing of 6.02 mm. The SCS-HDCCs prepared in this study offers economic and environmental benefits by reducing economic costs and carbon emissions through transporting raw materials from the continent. The research results have guiding significance for the construction of islands and reefs by SCS-HDCC.

在支持可持续发展战略的背景下，离岛工程建设有利于促进海洋资源开发，缓解日益严峻的资源冲突。然而，海洋工程面临极端天气和自然灾害，需要具有高延性、耐久性和裂缝控制能力的混凝土。本研究评估了使用海水和珊瑚砂代替淡水和河砂制备高延展性水泥基复合材料（SCS-HDCC）的可行性。结果表明，由于珊瑚砂表面粗糙、比表面积高、强度低，增加珊瑚砂替代会引入缺陷并扩大骨料-基质界面区。珊瑚砂的内部固化可增强致密性并减少有害毛孔。在海水和珊瑚砂的双重作用下，SCS-HDCC基体更加坚韧，纤维拔出过程中的损伤和堵塞现象变得明显，纤维与基体界面区的滑移硬化系数增大。SCS-HDCC具有令人满意的延展性（高达1.18％），初始开裂强度为4.18MPa，极限拉伸强度为5.66MPa，裂纹宽度为71.2±6.74μm，平均裂纹间距为6.02mm。本研究中制备的 SCS-HDCC 通过从非洲大陆运输原材料来降低经济成本和碳排放，从而提供经济和环境效益。研究成果对SCS-HDCC岛礁建设具有指导意义。