This study investigates the possibility of using sea sand instead of silica sand in producing engineered cementitious composites (ECC), the optimal mix proportion, mechanical behavior and the erosive effect of chloride ion on sea sand ECC (SECC). Nine groups of SECC specimens were prepared based on orthogonal test design, cured for uniaxial tensile, uniaxial compression and fracture energy tests. Roundness and sphericity of sea sand and silica sand were quantified by digital microscopy. The microstructure and composition of SECC were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mix proportions of SECC with tensile strain capacity of more than 2% and compressive strength of more than 60 MPa obtained. The factor analysis of these serial tests showed that both the contents of fly ash and sea sand have significant effect on the compressive strength and tensile strain capacity of SECC. Fracture energy test showed that the matrix fracture toughness of SECC increases significantly with increasing sea sand content. The XRD analysis showed that the addition of metakaolin can enhance the ability of SECC to bind chloride ions, and with the increase of chloride ion content, this ability of SECC to bind chloride ion will be improved. The results of this study provide further evidence of the feasibility of using sea sand in the production of ECC to meet the requirements of diverse concrete components on ductility and durability.

中文翻译：

---

使用海砂和偏高岭土开发工程水泥基复合材料

本研究调查了使用海砂代替硅砂生产工程胶凝复合材料 (ECC) 的可能性、最佳配合比、力学行为以及氯离子对海砂 ECC (SECC) 的侵蚀作用。基于正交试验设计制备9组SECC试样，固化进行单轴拉伸、单轴压缩和断裂能试验。海砂和硅砂的圆度和球形度通过数码显微镜量化。通过扫描电子显微镜 (SEM) 和 X 射线衍射 (XRD) 对 SECC 的微观结构和成分进行了表征。得到拉伸应变能力大于2%、抗压强度大于60 MPa的SECC配合比。这些系列试验的因素分析表明，粉煤灰和海砂的含量对SECC的抗压强度和拉伸应变能力都有显着影响。断裂能试验表明，随着海砂含量的增加，SECC的基体断裂韧性显着增加。XRD分析表明，偏高岭土的加入可以增强SECC结合氯离子的能力，并且随着氯离子含量的增加，这种SECC结合氯离子的能力会提高。这项研究的结果进一步证明了在 ECC 生产中使用海砂的可行性，以满足不同混凝土构件对延展性和耐久性的要求。断裂能试验表明，随着海砂含量的增加，SECC的基体断裂韧性显着增加。XRD分析表明，偏高岭土的加入可以增强SECC结合氯离子的能力，并且随着氯离子含量的增加，这种SECC结合氯离子的能力会提高。这项研究的结果进一步证明了在 ECC 生产中使用海砂的可行性，以满足不同混凝土构件对延展性和耐久性的要求。断裂能试验表明，随着海砂含量的增加，SECC的基体断裂韧性显着增加。XRD分析表明，偏高岭土的加入可以增强SECC结合氯离子的能力，并且随着氯离子含量的增加，这种SECC结合氯离子的能力会提高。这项研究的结果进一步证明了在 ECC 生产中使用海砂的可行性，以满足不同混凝土构件对延展性和耐久性的要求。