硬化混凝土原始用水量的测定方法

Method of determination original water content in hardened concrete

基于混凝土在拌和、成型和养护等各个阶段,其内部总的含水量不变的原理,在已知试样总质量的条件下,采用锻烧法和热重分析法分别测定试样的含水率,进而汁算出硬化混凝土的原始用水量。煅烧法测定了混凝土试样加热到700℃时的质量损失,研究了不同破碎粒径对原始用水量测定结果的影响,并比较了试验值和实际值的误差。热重分析法测定了混凝土试块中的水泥浆体从20℃分别加热到700、1 000℃时的质量损失,探究了试样的质量损失与混凝土实际用水量之间的数学关系表达式。结果表明,热重分析法和煅烧法都可以用于测定硬化混凝上的原始用水量。当试样粒径在9.5-25 mm之间时,通过煅烧法测定的用水量结果与实际用水量之间的误差在10%以内。

It studied the feasibility of calcination method and thermogravimetric analysis to determination the original water content in hardened concrete with the acknowledgement of weight of sample.Both of these two methods are based on the constant of total water con- tent in concrete during the processing of mixing, setting and curing.Calcination method detected the mass loss of concrete sample which heated to 700 ℃ .And the representative sample size to .determinate water content in hardened concrete and the error of test results were studied.Thermogravimetric analysis detected the mass loss of cement paste of concrete samples which heated to 700 ℃ and 1 000 ℃ respectively.The mathematical relationship between detected results and actual water content was studied.Test results show that, both of the two methods can be used to determinate original water content in hardened concrete.And the minimal error of results by calcination method is under 10% when the sample size is between 9.5-25 mm.