高性能混凝土中自干燥效应的研究

Study on Self-desiccation Effect of High Performance Concrete

关键词:  高性能混凝土  自干燥效应  水胶比  矿物掺和料  非线性  龄期

Key words:  autogenous relative humidity,self-desiccation effect, effective water to binder ratio, non-linear

摘要:

研究了水胶比、矿物掺和料种类及掺量对由混凝土自干燥引起的自身相对湿度变化的影响，提出了矿物自干燥效应系数k与有效水胶比re等2个参数，并对试验结果进行了非线性拟合分析．结果表明，在不同龄期下，混凝土自身相对湿度下降值均随水胶比的减小而增大．水胶比小于0．4的混凝土其自身相对湿度变化规律可用非线性方程表征，有效水胶比rc可有效地反映不同龄期下矿物掺和料种类和掺量等变量对混凝土自干燥效应的影响程度．

Abstract:

Effects of water to binder ratio (m_W/m_B), types and content of mineral admixtures on autogenous relative humidity (ARH) change of concrete resulting from self-desiccation were studied. The parameters of coefficient of mineral self-desiccation-effect k and effective water to binder ratio r_e were proposed, and experimental results were fitted non-linearly and analyzed using these proposed parameters. It is indicated from the results that ARH reduction of concrete with ages inereases with decrease of water to binder ratio. The ARH change laws of concrete with water to binder ratio lower than 0.4 can be expressed with a non-linear equation. The extent to the effect of types and content of mineral admixtures on ARH reduction of concrete resulting from self-desiccation can be reflected by the parameter of the effective water to binder ratio r_e effectively.