干热环境下钢纤维-水泥基材料增强增韧效果影响研究  

Study on reinforcing and toughening effect of steel fiber on cementitious materials under dry thermal environment

作　　者：杨家雷 周崇旭 李贺龙 谢文 邹烽 李嘹 崔圣爱[2] YANG Jialei;ZHOU Chongxu;LI Helong;XIE Wen;ZOU Feng;LI Liao;CUI Shengai(China Nuclear Industry Huachen Construction Engineering Co.,Ltd.,Xi'an 712000,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]中核华辰建筑工程有限公司,陕西西安712000 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《混凝土》2024年第1期110-115,共6页Concrete

基　　金：国家自然科学基金(51678492);成都市科技计划项目(2021-YF05-00138-SN);四川省科学技术厅中央引导地方科技发展项目(2021ZYD0045)。

摘　　要：为了研究干热环境下钢纤维对水泥基材料的增强增韧效果,以高地温隧道干热环境为背景,通过调研将隧道的围岩温度分为4个等级(40℃、60℃、80℃和100℃)并设置相应的模拟环境,通过力学性能试验研究不同干热环境对水泥砂浆强度、钢纤维与水泥砂浆界面黏结性和钢纤维拔出功的影响,分析干热环境的劣化机理,最后通过钢纤维混凝土断裂性能试验进行对比验证。主要得到结论:(1)干热环境在早期有利于水泥砂浆抗压强度及钢纤维与水泥砂浆界面黏结强度的增长。7 d龄期以后,干热环境下水泥砂浆抗压强度及钢纤维与水泥砂浆界面黏结强度明显低于标准养护环境,下降的程度与温度呈正相关。(2)干热环境下的钢纤维-水泥砂浆的拔出功大于标准养护条件下的拔出功,表明干热环境可以提高钢纤维的增韧效果,但是温度过高钢纤维的增韧效果下降。(3)随着温度的升高钢纤维-混凝土试件的断裂能均呈现先增大后减小的趋势,且断裂能在60℃时出现最大值。In order to study the reinforcing and toughening effect of steel fiber on cementitious materials under dry thermal environment,it takes the dry thermal environment of high ground temperature tunnel as the background,divides the temperature of tunnel surrounding rock into four levels(40℃,60℃,80℃and 100C)and setsup thecorrespondingsimulated environment throughresearch,and studies the effects of different dry thermal environments on the strength of cement mortar,interfacial bonding between steel fiber and cement mortar and steel fiber through mechanical property tests.The effects of different dry thermal environments on cement mortar strength,steel fiber-cement mortar interfacial bonding and steel fiber pull-out work were investigated through mechanical property tests,the deterioration mechanism of dry thermal environment was analyzed,and finally the fracture performance of steel fiber concrete was verified by comparison.The following conclusions were mainly obtained:(1)The dry hot environment is favorable to the growth of the compressive strength of cement mortar and the interfacial bond strength of steel fiber and cement mortar in the early stage.After 7 days the compressive strength of cement mortar and the interfacial bond strength of steel fiber and cement mortar in the dry hot environment are significantly lower than those in the standard curing environment,and the degree of decline is positively correlated with the temperature.(2)The pull-out work of steel fiber-cement mortar under dry heat environment is greater than that under standard curing conditions,indicating that the dry heat environment can improve the toughening effect of steel fiber,but the toughening effect of steel fiber decreases when the temperature is too high.(3)With the increase of temperature,the fracture energy of steel fiber-concrete specimens showed a trend of increasing and then decreasing,and the maximum value of fracture energy appeared at 60 C.

关 键 词：围岩温度 干热环境 黏结强度 纤维拔出功 断裂能 

分 类 号：TU528.041[建筑科学—建筑技术科学]