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膨胀剂对混凝土的补偿收缩和性能退化机理研究
MECHANISM RESEARCH OF EXPANSIVE AGENT ON THE COMPENSATING SHRINKAGE AND PERFORMANCE DEGRADATION OF CONCRETE
【Author】 DONG Yisen;FANG Xunke;WU Yingdong;ZHENG Zaofeng;Zhejiang Greentown Architectural Design Co.Ltd;Sunac China Holdings Southeast Regional Company;
【机构】 浙江绿城建筑设计有限公司; 融创中国东南区域公司;
【摘要】 通过试验模拟不同质量分数的膨胀剂对混凝土前期的补偿收缩作用和后期的性能退化特点,从不同侵蚀时间后混凝土的表观特征、质量变化规律、混凝土中硫酸根离子分布、侵蚀深度、混凝土轴心抗压强度、劈裂抗拉强度等方面全面衡量膨胀剂对混凝土性能影响的变化特征;讨论膨胀剂溶液质量分数、侵蚀龄期对混凝土性能变化规律的影响;结合SEM图像分析混凝土内部的微观结构特征,从宏观和微观两个层面上揭示了膨胀剂对混凝土前期的补偿收缩作用及后期性能退化的演变机理,从而为补偿收缩混凝土在实际工程中的应用提供了设计依据。试验结果表明,混凝土的表观特征和性能损伤模式与膨胀剂溶液的质量分数和侵蚀龄期有关。SEM微观测试结果表明,混凝土宏观力学性能的退化都是微观结构的变化在宏观上的反应,微观结构的变化规律与宏观力学性能相符。
【Abstract】 Some experiments were conducted to simulate the compensating shrinkage and performance degradation of concrete under different mass fraction of expansive agent. The parameters were evaluated by apparent characteristics of concrete,weight changes,profile of sulfate ions in concrete,erosion depth,compressive and splitting tensile strengths with erosion time in order to reveal the mechanism of expansive agent attack to the performance of concrete.The effects such as the mass fraction of expansive agent solution and the attacked time on the damage accumulation were analyzed. According to the SEM images,the evolution mechanism was achieved by analyzing the microstructures of concrete at different erosion periods from both macro and micro levels. So as to provide a design basis for the application of compensating shrinkage concrete in practical engineering. Experimental results indicated that the apparent characteristics and performance damage of concrete are related to the mass fraction and erosion periods of expansive agent solution. The microscopic structure of material was studied by the SEM scanning tests,which results showed that the deterioration of the physical and mechanical properties of concrete were controlled by the microscopic changes in the material,and the changing regularity of the microstructure had a good agreement with the macroscopic mechanical properties.
【Key words】 expansive agent; concrete; compensating shrinkage; performance degradation; microstructure;
- 【会议录名称】 《工业建筑》2018年全国学术年会论文集(上册)
- 【会议名称】《工业建筑》2018年全国学术年会
- 【会议时间】2018-06-20
- 【会议地点】中国北京
- 【分类号】TU528
- 【主办单位】《工业建筑》编委会、工业建筑杂志社有限公司