冻融环境下矿物掺合料混凝土与钢筋间黏结性能

Bonding properties between reinforcing bars and concrete containing mineral admixtures in freeze-thaw environment

为了探讨冻融环境下不同矿物掺合料对混凝土与钢筋之间黏结性能的影响,选用粉煤灰、磨细矿渣和硅灰3种混合材设计了4种矿物掺合料钢筋混凝土试件,采用快速冻融试验和黏结拉拔试验方法,研究了随着冻融循环次数增加各组试件的黏结强度及黏结破坏形式的退化规律。试验结果表明:硅灰与磨细矿渣的复合掺入提高了钢筋混凝土的黏结抗冻耐久性能,而粉煤灰的单掺加入对冻融环境下钢筋混凝土之间的黏结强度以及黏结延性都是不利的。因此,对于寒冷地区的钢筋混凝土结构建议粉煤灰与硅灰或磨细矿渣复合掺加使用。

For the purpose of studying the effect of varying proportions of mineral admixtures on bonding properties between reinforcing bars and concrete in freeze-thaw environment, four-group reinforced concrete specimens containing three common mineral admixtures, such as fly ash （FA）, ground slag（GS ） and silica fume （ SiF ）, were subjected to quick freeze-thaw test and pull-out test, and the degradation of bonding proper- ties between reinforcing bars and concrete with the increase of freeze-thaw cycle times was evaluated by the bonding strength and bonding failure mode.Results of this study show that mineral admixtures compounded with silica fume ground and slag improved the frost resistance of bonding properties, but the bonding strength and bonding ductility of the concrete specimens with fly ash along were shown decreasing with the increasing freeze-thaw actions.Thus, in the frigid zones, the compound addition of fly ash with silica fume or ground slag is recommended to using into reinforced concrete structure.