细集料的表面干湿状况对低强度等级混凝土性能的影响

Influences of moisture states of fine aggregate on performances of low-grade concrete

在施工现场,由于保护措施不当,细集料受雨水天气的影响,其表面有较大的含水率。但在施工中,一般通过测定现场用砂的含水率,对混凝土的砂用量和用水量做一个简单的调整,便进行施工,而很少考虑砂的表面干湿状况对混凝土性能的影响。为此,我们采用河砂和机制砂,研究了它们的表面干湿状态对低强度等级混凝土的工作性能、抗压强度、抗渗性能的影响,发现它们对混凝土的上述性能均有不同程度的影响。其中抗渗性能采用水压力抗渗高度和氯离子扩散系数两种方法来表征。

Moisture content of fine aggregate is large without proper protection on the field when subject to rain weather. The unit masses of sand and water in concrete are simply adjusted before construction without consideration of the influences. So, the influences of percent moisture content on workability, compressive strength, impermeability of concrete were researched with the object of natural sand and machine-made sand. The results show these performances are influenced by largely or lowly. Impermeability are explaned with the methods of water-pressure impermeability and chloride diffusion coefficient.