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张    宇

 

( 自贡市第四人民医院 , 自贡   643000)

摘  要: 超高性能混凝土  (UHPC) 因胶凝材料含量高而具有较大收缩变形 , 易引发开裂问题 。基于此 , 采用轻质膨胀页岩砂  (ES) 部分替代河砂 , 开展不同 ES 掺量时 UHPC 的抗压强度 、水化放热和收缩变形试验 , 研究 ES 掺量对抗压强度 、水化放热特性 、 自收缩变形 、干燥收缩变形的影响规律 。结果表明 : ES 替代 40%河砂时 UHPC 混合料的抗压强度仅损失 1. 2% ; 随 ES 掺量增加 , UHPC 的水化放热速率和累计水化放热量增大 、 自收缩和干燥收缩变形减小 、内部相对湿度和质量变化率提高 ; 掺 40%ES 时 , 自收缩 、干燥收缩变形分别降低65. 7%、26. 3% , 内部相对湿度提高 18. 6% ; 钢纤维可通过内约束机制降低干燥收缩变形 , 但会提供水分迁移通道而增加水分蒸发 , 引起附加收缩 , 当 ES 掺量低于 20%时 , 因约束作用干燥收缩减小 , 高于 20%后因水分蒸发干燥收缩增大 。研究成果可为控制 UHPC 收缩变形提供理论依据。

关键词: 轻骨料膨胀页岩砂 ; UHPC; 水化放热 ; 自收缩变形 ; 干燥收缩变形

中图分类号: TU528      文献标志码: A      文章编号: 1005-8249 (2026) 05-0014-07

DOI:10. 19860/j. cnki. issn1005-8249. 2026. 05. 003

 

ZHANG Yu

(Zigong Fourth People’s Hospital , Zigong 643000, China)

Abstract : Ultra-high performance concrete ( UHPC) exhibits significant shrinkage deformation due to its high cementitious content , which readily induces cracking issues. Therefore, lightweight expansive shale sand (ES) partially replaced river sand. Tests were conducted on the compressive strength, hydration heat release, and shrinkage deformation of UHPC at different ES dosages. The study investigated the influence patterns of ES dosage on compressive strength, hydration heat release characteristics, autogenous shrinkage deformation, and drying shrinkage deformation. Results indicate: When ES replaces 40% of river sand, UHPC mixture compressive strength decreases by only 1. 2% ; As the ES content increased, the hydration heat release rate and cumulative hydration heat of UHPC rose, while self-shrinkage and drying shrinkage decreased. Internal relative humidity and mass change rate also increased. At 40% ES content, self-shrinkage and drying shrinkage decreased by 65. 7% and 26. 3% , respectively, while internal relative humidity increased by 18. 6%. Steel fibers reduce drying shrinkage deformation through internal confinement mechanisms but also provide pathways for moisture migration, increasing evaporation and inducing additional shrinkage. When the ES content is below 20% , drying shrinkage decreases due to confinement effects; above 20% , drying shrinkage increases due to moisture evaporation.  These findings provide theoretical support for controlling shrinkag deformation in UHPC.

Key words: lightweight aggregate expanded shale sand; UHPC; hydration heat release; self shrinking deformation; dry shrinkage deformation

作者简介 : 张  宇 (1993—) , 男, 本科, 工程师 , 研究方向 : 建筑施工、绿色施工。