The inclusion of river sand in ECC alters the crack initiation and propagation behavior. As a result, the multiple cracking and pseudo strain-hardening of the river sand ECC (RS-ECC) are different from that of the typical micro-silica sand ECC. This study investigates the strain-hardening criteria for the RS-ECC by considering the matrix as a three-phase material containing pre-existing flaws along the sand/matrix interface with a given size distribution. Micromechanics is used to impart the new mechanisms in the analytic model for the steady-state crack analysis and the formulation of the strain-hardening criteria of ECC incorporating river sand. A probability-based approach is adopted to assess the strain-hardening potential of RS-ECC and validated with experimental results. Results show that the proposed model can predict the tensile properties of RS-ECC, which can be used to guide ingredients selection and components tailoring of RS-ECC to achieve required tensile strain-hardening performance.

中文翻译：

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河砂工程水泥复合材料 (ECC) 的多重开裂和应变硬化标准

ECC 中河沙的加入会改变裂纹的萌生和扩展行为。因此，河砂ECC（RS-ECC）的多重开裂和伪应变硬化与典型微硅砂ECC不同。本研究通过将基体视为三相材料，在给定尺寸分布的砂/基体界面上包含预先存在的缺陷，研究了 RS-ECC 的应变硬化标准。微观力学用于为稳态裂纹分析的解析模型和制定包含河砂的 ECC 应变硬化标准提供新的机制。采用基于概率的方法来评估 RS-ECC 的应变硬化潜力，并通过实验结果进行验证。结果表明，该模型可以预测RS-ECC的拉伸性能，可用于指导RS-ECC的成分选择和组件定制，以实现所需的拉伸应变硬化性能。