This study aims to explore the dynamic response of ultra-high performance engineered cementitious composites (UHP-ECC) incorporating waste crumb rubber (CR) at various temperatures, focusing on its potential to enhance the resilience and sustainability of civil infrastructures against low-velocity impacts. To date, the impact behaviour of UHP-ECC under low temperatures has rarely been explored. Firstly, natural river sand and waste tyre CR was utilized to prepare the UHP-ECC. Then, a series of mechanical tests, including compression test, flexural test and uniaxial tensile test were carried out to investigate the static mechanical properties of rubberised UHP-ECCs. In addition, the effects of different waste CR incorporations (0%, 5%, 10%, and 15%) and various temperatures (25 °C, −5 °C, −30 °C, −50 °C, −100 °C and −196 °C) were comprehensively investigated by low-velocity impact tests with constant impact energy. Lastly, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) model was introduced to evaluate the overall performance of UHP-ECC. It was found that the use of river sand and CR significantly enhanced the tensile ductility and impact toughness of UHP-ECC. Impact energy primarily dissipates through damage such as matrix crack initiation, propagation, and fibre pull-out/rupture within the specimen. Adding CR notably decreased stress fluctuations during impact at room temperature, facilitating steady state energy absorption. Moreover, the time to reach peak impact force decreased with decreasing temperature across all UHP-ECC groups. At room temperature during impact process, fibre failure mode is dominated by pull-out failure, while lower temperatures lead to increased fibre rupture at the cracking surface. In low-temperature conditions, the impact response of rubberised UHP-ECC necessitates a comprehensive consideration of the synergistic effects, including material contraction, fibre bridging capacity, rubber phase transition, and water freezing.

中文翻译：

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超高性能工程水泥基复合材料（UHP-ECC）在低速冲击下的动态响应：废橡胶掺入和低温的影响


本研究旨在探索掺有废旧橡胶粉（CR）的超高性能工程水泥基复合材料（UHP-ECC）在不同温度下的动态响应，重点关注其增强民用基础设施抵御低速冲击的弹性和可持续性的潜力。迄今为止，UHP-ECC 在低温下的冲击行为很少被探索。首先利用天然河沙和废轮胎CR制备UHP-ECC。然后，进行了一系列力学测试，包括压缩测试、弯曲测试和单轴拉伸测试，以研究橡胶UHP-ECC的静态力学性能。此外，不同废物 CR 掺入量（0%、5%、10% 和 15%）和不同温度（25°C、-5°C、-30°C、-50°C、-100°C）的影响C和-196°C）通过恒定冲击能量的低速冲击试验进行了全面研究。最后，引入了理想解相似度优先顺序技术（TOPSIS）模型来评估UHP-ECC的整体性能。结果发现，河砂和 CR 的使用显着提高了 UHP-ECC 的拉伸延展性和冲击韧性。冲击能量主要通过破坏（例如基体裂纹萌生、扩展以及样本内的纤维拉出/断裂）来消散。添加 CR 显着降低了室温冲击过程中的应力波动，有利于稳态能量吸收。此外，所有 UHP-ECC 组中达到峰值冲击力的时间随着温度的降低而缩短。在室温下，冲击过程中，纤维失效模式以拉拔失效为主，而较低的温度会导致裂纹表面的纤维断裂增加。 在低温条件下，橡胶化UHP-ECC的冲击响应需要综合考虑协同效应，包括材料收缩、纤维桥联能力、橡胶相变和水冻结。