高性能混凝土抗裂性能研究

THE RESEARCH ON THE CRACKING BEHAVIOR OF HIGH PERFORMANCE CONCRETE

  • 摘要: 该文对高性能混凝土的抗裂性能进行了系统的研究,主要包括:高性能混凝土收缩与抗裂性能的试验方法,研制出一种测试混凝土抗裂性能的诱导开裂试验方法,该方法避免了混凝土裂缝出现位置的随机性以及混凝土塑性沉降引起的材料不均匀等带来的测试结果不准确,同时研制出一种多点、实时、自动监测混凝土试件开裂时间的系统,可应用于测试混凝土早期的裂缝出现时间;进行了大量自生收缩试验和干燥收缩试验,对影响高性能混凝土自生收缩和干燥收缩的因素进行了深入的研究,提出了减少收缩变形的混凝土原材料选用和粉煤灰及矿渣单掺与多掺的最佳掺量,提出了高性能混凝土自生收缩和干燥收缩计算模型;采用平板诱导开裂法和圆环测试系统进行了大量的抗裂性能试验,深入研究了混凝土原材料特别是粉煤灰及矿渣影响高性能混凝土抗裂性能的规律,提出了实现高抗裂性能的混凝土原材料选用和粉煤灰及矿渣单掺与多掺的最佳掺量;研究成果成功地应用于实际工程中,取得了显著的技术和经济效益。

     

    Abstract: The cracking behavior of high performance concrete (denoted as HPC) was systemically studied in the paper. A new test method for concrete cracking behavior, called inducing crack method, is proposed. The method overcomes the shortages of the conventional test method like random crack occuring and uneven material in specimens. The shortages affect the accuracy of testing. A testing system is developed, which can test the age of crack automatically with multi-points monitors. The factors which affect the autogenous shrinkage and drying shrinkage of HPC are studied, and then a method to select raw materials and determine the optimal content and proportions of fly ash and slag to reduce the shrinkage of HPC is proposed. The calculation models of autogeous shrinkage and drying shrinkage of HPC are also put forward, and the cracking behaviors of HPC are studied by the inducing crack method and the ring test system. Moreover, this paper studies the effects of raw materials, especially fly ash and slag, on the cracking behaviors of HPC, and then proposes a method to select raw materials and determine the optimal content and proportions of fly ash and slag to achieve the high anticracking behavior of HPC.

     

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