【作者】 李进辉；

【导师】 周明凯； 李北星；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2008， 硕士

【摘要】 高性能轻集料混凝土(HPLC)具有轻质高强、高工作性、良好体积稳定性、优良耐久性、高抗震性和综合造价低等特点,特别适用于大跨度桥梁以及处于严酷环境下的海洋结构物,其应用于桥梁工程具有巨大的技术经济优势和非常广阔的前景。本论文通过对高性能轻集料混凝土工作性能、物理力学性能、体积稳定性能、耐久性的系统实验研究以及微观结构的初探,探明了高性能轻集料混凝土性能的影响因素及其变化规律,初步揭示了轻集料混凝土高性能化的机理;结合调研和室内实验提出了高性能轻集料混凝土用于桥梁工程的应用技术,为该类材料在实际桥梁工程中的推广和应用提供了理论支持和技术保障。本文进行的主要工作和取得的主要成果如下:在优选适合桥梁工程用高性能轻集料的基础上,系统研究了高性能轻集料混凝土匀质性的影响因素,并对其泵送性能进行了初探,提出了以坍落度、扩展度、分层度为控制指标并结合目测的工作性评价体系,总结了匀质性的控制技术和方法,得出了工作性能良好并适合泵送的高性能轻集料混凝土的配制方法。通过实验,系统研究了轻集料、矿物掺合料、配合比参数、纤维和外加剂等对硬化高性能轻集料混凝土的物理力学性能、体积稳定性能以及耐久性能的影响规律,提出了桥梁用高性能轻集料混凝土的强度提高技术、体积增稳技术和耐久性提高措施。配制出了坍落度为240±20mm、扩展度为450～650mm,具有优良工作性和匀质性,不分层、不离析、低收缩、高耐久性,静压弹模大于30GPa的适用于桥梁工程的LC40～LC60高性能轻集料混凝土。采用XRD并结合SEM对轻集料及轻集料混凝土的界面微观结构进行了研究,初步揭示了轻集料混凝土高性能化的机理。最后,结合调研和室内实验系统研究了高性能混凝土的制备、施工、质量控制以及检验和验收等桥梁工程应用的关键技术,为其在实际桥梁工程中的应用提供了重要的参考。更多还原

【Abstract】 High performance lightweight aggregate concrete (HPLC) is a kind of lightweight environment-protected building material with high strength, good workability, good volume stability and durability, high aseismic performance and low comprehensive cost, which suits for large scale engineering such as high bridges and some important engineering which has a complicated geography condition or a special command for durability such as marine environment. Therefore, HPLC has great technical economic superiorities and broad prospect in the large scale bridge engineering. In the paper based on systemic experiment studies of workability, physical and mechanical properties, volume stability, durability and preliminary studies of microstructure, influencing factors of properties of HPLC and its rule were proved up, and mechanism of high performance of lightweight aggregate concrete was preliminarily revealed. Application technology in bridge engineering project was put forwarded by laboratory experiments and investigation, which provided theoretical and technical support for its actual application.The main research work and compliments of this paper are:On the basis of selection of high-performance lightweight aggregate for bridge project, influencing factors of uniformity of HPLC was systematically studied, and pumpability was also preliminarily studied. In additional, an evaluation system of workability of HPLC was established, which included slump, slump flow, segregation degree and visual measurement of the non-uniform level of cement paste and aggregate. And the control technique of uniformity of HPLC was summarized as well. Therefore, a method of preparation of HPLC with good workability was educed.The influencing rule of lightweight aggregate、mineral admixture、parameters of mix proportion、types of fiber and admixture on physical and mechanical properties, volume stability, durability of HPLC was systematically studied. Then, the technique of improvement of strength、volume stability and durability of HPLC was proposed. So, LC40—LC60 HPLC with the slump about 240±20mm, the slump flow between 450mm and 650mm, good workability and uniformity, the elastic modulus over 30GPa, small shrinkage, long durability was prepared.The microstructure of lightweight aggregate and interface microstructure between lightweight aggregate and harden cement paste were analyzed through XRD and SEM. So, the mechanism of high-performance of lightweight aggregate concrete was preliminarily revealed.In the end, the key technologies, such as preparation, construction, quality control、check and accept etc., for bridge engineering application of HPLC were analyzed systematically, which gave an essential support for the produce and application of HPLC.更多还原