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Abstract：
This study utilizes polyethylene terephthalate (PET) aggregate of different particle sizes (21 μm, 107 μm, and 244 μm) to replace natural aggregate in the preparation of PET-modified engineered cementitious composite (P-ECC). The impact of PET aggregate particle size on the performance of P-ECC is examined herein from micro to macro levels. The focus is on the influence patterns and mechanisms of P-ECC\'s workability, its basic mechanical properties, and its microstructure. Crack parameters are processed to quantitatively analyze crack development patterns. Using microscopic techniques, the interfacial transition zone (ITZ) between different aggregates and the cement matrix is compared, and the failure mechanism of P-ECC is analyzed. The results show that the incorporation of PET aggregate can improve P-ECC\'s workability and reduce its self-weight, but incorporation has a negative effect on compressive strength. Additionally, the particle size of PET aggregate significantly affects the uniaxial tensile performance of P-ECC. Compared to conventional ECC, the tensile strength of P-S (21 μm PET) increased the most markedly (18.1%), and the ultimate tensile strain of P-M (107 μm PET) increased the most markedly (66.0%), with both demonstrating good crack control and deformation energy dissipation capabilities. The uniaxial tensile performance of P-L (244 μm PET) was lower than that of the conventional ECC. Microscopic tests revealed that the increase in PET aggregate particle size enlarges the ITZ width and its surrounding pores. Appropriate pore enlargement is beneficial for enhancing tensile ductility, while excessive pores have a negative effect. The study results reveal the impact of PET aggregate particle size on the performance of P-ECC, providing new insights for the performance optimization of ECC.
摘要：
本研究利用不同粒径的聚对苯二甲酸乙二醇酯（PET）骨料（21μm，107μm,和244μm），以代替天然骨料制备PET改性的工程胶凝复合材料（P-ECC）。本文从微观到宏观水平检查PET聚集体粒度对P-ECC性能的影响。重点是P-ECC可操作性的影响模式和机制，其基本机械性能，和它的微观结构。处理裂纹参数以定量分析裂纹发展模式。使用显微技术，比较了不同骨料与水泥基体之间的界面过渡区(ITZ)，分析了P-ECC的失效机理。结果表明，掺入PET骨料可以提高P-ECC的可加工性，降低其自重，但掺入对抗压强度有负面影响。此外,PET骨料的粒径显著影响P-ECC的单轴拉伸性能。与传统ECC相比，P-S(21μmPET)的拉伸强度增加最显著(18.1%)，P-M（107μmPET）的极限拉伸应变增加最明显（66.0％），具有良好的裂纹控制和变形耗能能力。P-L（244μmPET）的单轴拉伸性能低于常规ECC。显微镜测试表明，PET骨料粒径的增加扩大了ITZ宽度及其周围的孔。适当扩大孔隙有利于提高拉伸延性，而过多的毛孔有负面影响。研究结果揭示了PET骨料粒径对P-ECC性能的影响,为ECC的性能优化提供新的见解。
