To combat global warming, the development of eco-friendly ultra-high performance concrete (UHPC) has become one of the current research hotspots. Understanding the relationship between composition and performance of eco-friendly UHPC from a meso-mechanical point will be of great significance in proposing a more scientific and effective mix design theory. In this paper, the 3D discrete element model (DEM) of an eco-friendly UHPC matrix was constructed. The mechanism of the effect of the interface transition zone (ITZ) properties on the tensile behavior of an eco-friendly UHPC matrix was studied. The relationship between composition, ITZ property, and tensile behavior of eco-friendly UHPC matrix was analyzed. The results show that ITZ strength influences the tensile strength and cracking behavior of eco-friendly UHPC matrix. The effect of ITZ on the tensile properties of eco-friendly UHPC matrix is more significant than that of normal concrete. The tensile strength of UHPC will be increased by 48% when the ITZ property is changed from normal condition to perfect. Improving the reactivity of the binder system of UHPC will improve the performance of ITZ. The cement content in UHPC was reduced from 80% to 35%, and the σITZ/σPaste was reduced from 0.7 to 0.32. Both nanomaterials and chemical activators can promote the hydration reaction of the binder material, which in turn leads to better ITZ strength and tensile properties for an eco-friendly UHPC matrix.

中文翻译：

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生态友好型 UHPC 基体的组成、ITZ 特性和拉伸行为之间关系的离散元模拟

为应对全球变暖，开发环保型超高性能混凝土（UHPC）已成为当前的研究热点之一。从细观力学角度理解生态友好型UHPC的组成与性能之间的关系，对于提出更加科学有效的配合比设计理论具有重要意义。在本文中，构建了环保型 UHPC 矩阵的 3D 离散元模型 (DEM)。研究了界面过渡区 (ITZ) 特性对生态友好型 UHPC 基体拉伸行为的影响机制。分析了生态友好型 UHPC 基体的组成、ITZ 性能和拉伸行为之间的关系。结果表明，ITZ 强度会影响生态友好型 UHPC 基体的拉伸强度和开裂行为。ITZ 对环保 UHPC 基体的拉伸性能的影响比普通混凝土更显着。当ITZ性能从正常状态变为完美状态时，UHPC的抗拉强度将提高48%。提高 UHPC 粘合剂体系的反应性将提高 ITZ 的性能。UHPC 中的水泥含量从 80% 降低到 35%，σITZ/σPaste 从 0.7 降低到 0.32。纳米材料和化学活化剂都可以促进粘合剂材料的水合反应，从而为环保型 UHPC 基体带来更好的 ITZ 强度和拉伸性能。提高 UHPC 粘合剂体系的反应性将提高 ITZ 的性能。UHPC 中的水泥含量从 80% 降低到 35%，σITZ/σPaste 从 0.7 降低到 0.32。纳米材料和化学活化剂都可以促进粘合剂材料的水合反应，从而为环保型 UHPC 基体带来更好的 ITZ 强度和拉伸性能。提高 UHPC 粘合剂体系的反应性将提高 ITZ 的性能。UHPC 中的水泥含量从 80% 降低到 35%，σITZ/σPaste 从 0.7 降低到 0.32。纳米材料和化学活化剂都可以促进粘合剂材料的水合反应，从而为环保型 UHPC 基体带来更好的 ITZ 强度和拉伸性能。