高岩温对衬砌混凝土耐久性能的影响

Effect of High Rock Wall Temperature on Performance of Lining Concrete

通过实验室模拟高岩温、低湿度施工环境,研究了高岩温对单掺粉煤灰和双掺粉煤灰与矿粉混凝土耐久性能的影响规律,并对不同养护温度下的混凝土试样进行了微观形貌分析,从微观角度探讨了不同养护温度对混凝土抗氯离子渗透性能和抗碳化性能的影响机理。结果表明:高温、低湿养护制度下获得的水化产物分布不均匀,水分蒸发过快,导致了混凝土内部结构疏松;单掺粉煤灰和双掺粉煤灰与矿粉的C30衬砌混凝土的抗氯离子渗透性能均随着养护温度的升高而降低,当养护温度低于80℃时,双掺粉煤灰与矿粉的混凝土电通量值低于单掺粉煤灰的混凝土,当养护温度达到80℃时,前者大于后者;养护温度升高增大了混凝土内部的孔隙率,降低了混凝土的密实度,混凝土抗碳化性能随着温度的升高逐级下降。

Through laboratory simulation of high rock wall temperature, low-humidity construction environment, the influences of high rock waU temperature on the durability of concrete mixed singly with fly ash and concrete mixed with both fly ash and slag powder were investigated. Based microscopic morphology analyses of concrete specimens cured at different temperature, the influencing mechanism of different curing temperature on the ability to chloride ions penetration resistance and the ability of carbonation resistance of concrete was discussed, from the microscopic point of view. The results show that under high temperature, low-humidity curing system, the uneven hydration products and the excessive water evaporation lead to a more loose internal structure of concrete ; The ability to chloride ions penetration resistance of concrete singly mixed with fly ash and concrete mixed with both fly ash and slag powder decreases as the curing temperature rise. When the curing temperature is below 80℃, the electric flux of the concrete mixed with both fly ash and slag powder is lower than that of the concrete singly mixed with fly ash, when the curing temperature reaches 80℃, the former is higher than the later; With curing temperature rising, the porosity of the concrete increases, the density of the concrete reduces and the ability of carbonation resistance of the concrete decreases.