超声回弹综合法推定纤维纳米混凝土强度及经历高温

Evaluation of Compressive Strength and the Highest Exposure Temperature of Fiber and Nanosized Materials Reinforced Concrete by Ultrasonic Rebound Combined Method

摘要:

通过纤维纳米混凝土立方体试块高温前后超声、回弹和抗压强度试验，探讨了钢纤维、纳米SiO2和纳米CaCO3对高温前后超声波速和回弹值的影响以及纤维纳米混凝土抗压强度、经历最高温度与超声波速和回弹值的相互关系.结果表明:在混凝土中掺入钢纤维、聚丙烯纤维和纳米材料，改善了混凝土微观结构，使高温前后超声波速和回弹值均有一定程度提高；纤维纳米混凝土高温后抗压强度与超声波速和回弹值具有良好的相关性，超声回弹综合法适用于推定纤维纳米混凝土高温抗压强度及经历最高温度.通过对试验数据的回归分析，建立了超声回弹综合测强曲线及推定经历最高温度的公式.

Abstract:

By the experiments of ultrasonic pulse velocity, rebound and compression, the effect of steel fiber and nanosized materials on ultrasonic pulse velocity（UPV） and rebound number（RN) of fiber & nanosized materials reinforced concrete（FNMRC） before and after exposition to high temperature, and the relationship of compressive strength of FNMRC, the highest exposure temperature were investigated. Test data indicates that the suitable usage of steel fiber，polypropylene fiber and nanosized materials improves the microstructure of concrete, increases its UPV and RN in certain degree. Because there is a good regressive relationship between compressive strength and UPV & RN, the ultrasonic rebound combined method is suitable for evaluating compressive strength and the highest exposure temperature of FNMRC. Based on the regression analysis of test data, the ultrasonic rebound strength curve and the model for evaluating the highest exposure temperature were proposed.