快速修补砂浆的制备及性能研究
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摘要
我国高速铁路、高速公路、城市轨道交通等交通工程承受高频振动荷载和复杂环境荷载的共同作用,混凝土结构容易出现钢筋锈蚀、开裂、露筋缺损现象,且该类修复工程具有作业时间短、材料性能要求高等特点。针对上述情况,使用无机矿物早强剂制备了快速修补砂浆,并对其工作性能、力学性能、粘接耐久性能及早强作用机理进行了系统研究。结果表明:快速修补砂浆终凝时间可根据工程需要在8～30 min范围内进行调节;无机矿物早强剂Al/S比值较低,在水化早期形成钙矾石(AFT)提高砂浆早期力学性能,水化后期AFT基本没有向AFm(单硫型水化硫铝酸钙)转变,加之AFT微膨胀性能,提高了砂浆密实度及长龄期力学性能;钢纤维可显著提高砂浆抗折强度及早期抗压强度;冻融循环后,砂浆黏结强度依然满足混凝土加固设计规范要求,具有良好的黏结耐久性;制备的修补砂浆应用于铁路轨枕侧向挡肩修复工程,运行一年,效果良好。
Traffic engineering like high-speed railways,highways and urban rail transit are under high frequency vibration load and combination load of complex environment. Steel corrosion,concrete crack and concrete defect of traffic engineering is much easier to occur than civil buildings. Furthermore,repair project of traffic engineeringis characterized by short operation time and high material performance requirement. Quick-setting repair mortar are prepared based on the above situation,and their working performance,mechanical property,bond strength and durability are studied. Results show that: Final setting time of the quick-setting repair mortar can be adjusted during 8-30 min. Inorganic mineral early strength agent generate ettringite (trisulfide hydrated calcium thioaluminate,AFT) during early hydration and improve early mechanical properties of repair mortar. As Al/S is lower,few AFT transferred into single sulfur hydrated calcium thioaluminate (AFm),and long-term density and mechanical properties of repair mortar can also be promoted. Steel fiber can significantly increase the flexural strength and early compressive strength of mortar. After the freeze-thaw cycle,the bonding strength of mortar still meets the requirements of the design specification of concrete reinforcement. The prepared repair mortar was applied to the repairing project of concrete sleepers side retaining shoulder,and has good bonding durability.
Traffic engineering like high-speed railways,highways and urban rail transit are under high frequency vibration load and combination load of complex environment. Steel corrosion,concrete crack and concrete defect of traffic engineering is much easier to occur than civil buildings. Furthermore,repair project of traffic engineeringis characterized by short operation time and high material performance requirement. Quick-setting repair mortar are prepared based on the above situation,and their working performance,mechanical property,bond strength and durability are studied. Results show that: Final setting time of the quick-setting repair mortar can be adjusted during 8-30 min. Inorganic mineral early strength agent generate ettringite (trisulfide hydrated calcium thioaluminate,AFT) during early hydration and improve early mechanical properties of repair mortar. As Al/S is lower,few AFT transferred into single sulfur hydrated calcium thioaluminate (AFm),and long-term density and mechanical properties of repair mortar can also be promoted. Steel fiber can significantly increase the flexural strength and early compressive strength of mortar. After the freeze-thaw cycle,the bonding strength of mortar still meets the requirements of the design specification of concrete reinforcement. The prepared repair mortar was applied to the repairing project of concrete sleepers side retaining shoulder,and has good bonding durability.
引文
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[4]周华新,刘加平,崔巩,等.超早期聚合物快速修补砂浆研制及粘结耐久性能研究[J].新型建筑材料,2013(1):15-19.
[5]田培,刘加平,王玲,等.混凝土外加剂手册[M].第一版,北京:化学工业出版社,2009:105-107.
[6]谭永山,余红发,姚祥,等.无缓凝剂磷酸镁修补砂浆的力学性能实验研究[J].南京航空航天大学学报,2018,50(1):138-144.
[7]姜淼,李晓明,金恒刚.聚合物快速修补砂浆的开发研究[J].低温建筑技术,2016,214(4):19-20.
[2]黄梅,李渠江.聚合物改性的道路快速修补砂浆研究[J].四川建材,2012,38(6):179-181.
[3]肖鹏,陈树芝.水泥混凝土路面湿法泵喷特种砂浆快速修补机械与工艺的试验研究[J].筑路机械与施工机械化,1996,13(6):4-7.
[4]周华新,刘加平,崔巩,等.超早期聚合物快速修补砂浆研制及粘结耐久性能研究[J].新型建筑材料,2013(1):15-19.
[5]田培,刘加平,王玲,等.混凝土外加剂手册[M].第一版,北京:化学工业出版社,2009:105-107.
[6]谭永山,余红发,姚祥,等.无缓凝剂磷酸镁修补砂浆的力学性能实验研究[J].南京航空航天大学学报,2018,50(1):138-144.
[7]姜淼,李晓明,金恒刚.聚合物快速修补砂浆的开发研究[J].低温建筑技术,2016,214(4):19-20.