冻融环境下TRC加固RC柱轴压性能的研究

Axial Capacity of RC Columns Strengthened with Textile-Reinforced Concrete under Freeze-Thaw Cycles

为探究冻融环境下纤维编织网增强混凝土(TRC)加固钢筋混凝土(RC)柱的轴压性能,本文开展了冻融循环次数、轴压应力和冻融循环耦合作用及短切纤维改性细粒混凝土等因素对TRC加固RC柱性能的研究.试验结果表明:冻融循环次数超过一定次数(20次),会造成TRC表面萌生细微的收缩裂缝,开始降低TRC约束效果,在冻融循环60次时,TRC加固RC柱的承载力降低达21.75%;轴压应力与冻融循环的耦合作用降低TRC加固RC柱的承载力及约束能力相对明显,轴压应力比率为0.4的试件的破坏形态发生改变;在TRC中掺入短切纤维可提高TRC加固柱的抗冻性.此外,掺入AR短切纤维的TRC在冻融环境下有助于提高加固柱的承载力,而掺入PVA短切纤维的TRC有助于增强加固柱的变形性能.

In order to study the axial capacity of RC columns strengthened with textile-reinforced concrete （TRC） under freeze-thaw cycles, this paper took the freeze-thaw cycles, the coupling effect of sustained axial load and freeze-thaw cycles, and short-cut fibers added into fine grained concrete into account. The experimental results indicated that when the number of freeze-thaw cycles was over a certain value （20 times）, the slight shrinkage cracks appeared on the TRC＇ surface, reducing the confinement effect of TRC, and when the number of freeze-thaw cycles was up to 60,the bearing capacities of TRC-strengthened RC columns reduced about 21.75%. The bearing capacities and confining abilities reduced apparently under the coupling effect of axial load and freeze-thaw cycles, and the failure mode of specimens whose sustained axial compressive stress was 0. 4 changed. Adding the short-cut fibers into fine grained concrete could improve the frost resistance of columns. Besides, the addition of AR-glass short-cut fibers to TRC could improve the columns＇ bearing capacities and adding the PVA short-cut fibers to TRC could enhance the deformation performance of columns.