回弹法检测高温后高强混凝土轴心抗压强度

Axial compressive strength of high strength concrete after high temperature by rebound method

为研究高温后高强混凝土的回弹法无损检测技术,对不同水胶比、历经不同最高温度、不同最高温度持温时长的117个高温后高强混凝土棱柱体试件采用普通回弹仪进行抗压强度检测试验。结果表明:混凝土回弹值随着历经最高温度的升高而先增加后下降,随持温时长的增加而稍有降低,随水胶比的降低对温度的敏感度降低;三个变化参数对高温后高强混凝土回弹值与轴心抗压强度的关系影响很小。运用最小二乘法对五种函数方程进行回归比较,得到了基于二次多项式的回弹法检测高温后高强混凝土轴心抗压强度测强曲线。

In order to study the non-destructive testing technology of high-strength concrete by rebound method after high-emperature,117 high-strength concrete prism specimens with different water-binder ratios,maximum temperatures and maximum temperatures holding time were inspected by rebound method for compressive strength.The results showed that the rebound value of concrete increases first and then decreases with the increase of the maximum temperature,and slightly decreases with the increase of the temperature holding time,and the sensitivity of concrete to temperature decreases with the decrease of water-binder ratio.The relationship between the rebound value of high-strength concrete and the axial compressive strength after high temperature is little affected by the three parameters.By using the least square method to compare the five functional equations,the curve of the axial compressive strength of high strength concrete is obtained by the rebound method based on the quadratic polynomial.