| 摘要: |
| 基于颗粒最紧密堆积原理，确定了超高性能混凝土的胶凝材料组成和轻集料颗粒级配，优化得到了轻集料超高性能混凝土(LUHPC)的基准配合比.研究了轻集料粒形、轻集料预吸水率和掺量对LUHPC工作性能和力学性能的影响规律，并利用超景深三维数码显微镜、扫描电子显微镜等探究了轻集料对LUHPC性能的影响机理.结果表明：轻集料的粒形和预吸水率是影响LUHPC工作性能和力学性能的关键因素；随着轻集料粒形由碎石形转变为球形，LUHPC的工作性能和力学性能均显著优化；随着轻集料预吸水率的增加，LUHPC工作性能改善，但抗压强度和劈裂抗拉强度均呈现先增加后降低趋势；随着轻集料掺量的增加，LUHPC工作性能和力学性能均先提升后降低；轻集料主要通过增大颗粒球形度、改善轻集料水泥石界面黏结性和预湿内养护来提升LUHPC的工作性能和力学性能. |
| 关键词: 轻集料 超高性能混凝土 粒形 预吸水率 工作性能 力学性能 |
| DOI：103969/j.issn.1007 9629202103008 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(51878003)；安徽省高校自然科学研究重大项目(KJ2019ZD55)；安徽省高校优秀青年人才支持计划重点项目(gxyqZD2019055)；安徽建筑大学博士启动基金项目(2018QD30) |
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| Effect of Lightweight Aggregate on Workability and Mechanical Properties of Ultra high Performance Concrete |
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ZHANG Gaozhan, WANG Yuxuan, GE Jingcheng, YANG Jun, WEI Qi
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School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
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| Abstract: |
| Based on the particle dense packing theory, the composition of cementitious materials and particle gradation of lightweight aggregate in ultra high performance concrete were determined. On this basis, the basic mix proportion of ultra high performance concrete with lightweight aggregate(LUHPC) was optimized. The effects of particle shape, pre absorption ratio and content of lightweight aggregate on the workability and mechanical properties of LUHPC were studied. Besides, the mechanism of the effect of lightweight aggregate on the properties of LUHPC was investigated by ultra depth field 3D digital microscope and scanning electron microscope. The results show that particle shape and pre absorption ratio are the key factors that determine the workability and mechanical properties of LUHPC. The workability and mechanical properties of LUHPC with spherical lightweight aggregate are superior to UHPC with crushed lightweight aggregate. With the increase of pre absorption of lightweight aggregate, the workability of LUHPC is improved, but the compressive strength and splitting tensile strength of LUHPC increase first and then decrease. With the increase of lightweight aggregate content, the workability and mechanical properties of LUHPC are improved first and then reduced. In addition, lightweight aggregate mainly improves the workability and mechanical properties of LUHPC by improving the sphericity of aggregate, the adhesion between lightweight aggregate and cement matrix and by providing internal curing effect. |
| Key words: lightweight aggregate ultra high performance concrete particle shape pre absorption ratio workability mechanical property |
