原位表层混凝土透气性测试方法精度影响因素

摘要

通过分析Autoclam透气性方法测试原理,研究了测试参数设置对混凝土透气系数测试精度的影响,提出了影响测试精度的主要因素.结果表明:测试时间和测试压力的变化对混凝土透气系数影响较小,而增大测试面积或减小测试腔体体积能够有效提高混凝土透气系数的测试精度;改进后的Autoclam测试方法能够有效区分“低水胶比、高密实度”混凝土的渗透性差别.%The working theory of the Autoclam air permeability test was proposed and key factors to affect the sensitivity were discussed.Results indicate that the sensitivity of Autoclam can be improved using a test ring with a larger internal diameter or a test chamber with a lower volume,while test duration and pressure intensity had no noticeable effect on the air permeability.Test sensitivity can be further improved by reducing the volume of air compressed to the levels which were typically used for assessing normal performance of concrete.It is found that the modified Autoclam is an in situ technique capable of measuring air permeability of HPC.