压弯荷载下再生砂浆的裂纹演变与氯离子扩散  

Cracking development and chloride ion penetration of recycled mortar under compression bending load

作　　者：应敬伟[1] 王威伻 苏飞鸣 YING Jingwei;WANG Weibeng;SU Feiming(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,Guangxi,China)

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004

出　　处：《建筑科学与工程学报》2024年第6期89-99,共11页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(52168015);广西大学学科交叉项目(202200227);广西自然科学基金项目(2023GXNSFAA026472)。

摘　　要：为了研究压弯荷载作用下再生砂浆的裂纹发展与氯离子的扩散规律,自制了一种氯盐荷载耦合装置,该装置包括压弯荷载加载装置和电加速快速氯离子迁移装置。通过该氯盐荷载耦合装置,对再生砂浆小梁进行了压弯加载与氯离子渗透。为了避免小梁在弯曲加载时提前破坏,在小梁的横向分别预先施加25%、50%、75%极限轴向压荷载,再竖向进行逐级加载,并结合数字图像相关(DIC)技术研究了加载过程中再生砂浆小梁的裂纹演变规律。同时设计了4种不同的压弯荷载组合,以RCM理论为基础,进行了压弯荷载作用下的电加速氯离子渗透试验。结果表明:在横向荷载为25%极限轴向压荷载时逐级加载竖向荷载,再生砂浆小梁呈现少筋梁的破坏特征;在横向荷载为50%、75%极限轴向压荷载时逐级施加竖向荷载,再生砂浆小梁呈现超筋梁的破坏特征;当再生骨料取代率小于50%时,增加压弯荷载值对小梁的氯离子扩散系数影响不大;当再生骨料取代率大于50%时,随着压弯荷载值的增加,砂浆小梁的氯离子扩散系数快速增加;在压弯荷载作用下,小梁的氯离子扩散系数呈现沿着竖向高度逐渐减小的趋势。In order to study the crack development and chloride ion penetration of recycled mortar under compression bending load,one chloride load coupling device was made,which included compression bending loading device and electrically accelerated rapid chloride ion migration device.Through the device,the recycled mortar girder was subjected to compression bending load and chloride ion penetration.In order to avoid the failure of girders under loading,the 25%,50%,75%ultimate axial compression load were applied in the transverse direction of the girders,then the vertical loading was carried out step by step,and the crack evolution law of the recycled mortar girders during loading was studied with digital image correlation(DIC)technology.Four different combinations under compression bending load were designed.Based on RCM theory,the electro-accelerated chloride ion penetration experiments under compression bending load were carried out.The results show that when the transverse load is 25%ultimate axial compression load and the vertical load is loaded step by step,the recycled mortar beam presents the failure characteristics of rare-reinforced beams.When the lateral load is 50%and 75%ultimate axial compressive load and the vertical load is loaded step by step,the recycled mortar beam presents the failure characteristics of the over-reinforced beam.When the replacement rate of recycled aggregate is less than 50%,increasing the compression bending load has little effect on the chloride ion penetration coefficient of the girder.However,when the replacement rate of recycled aggregate is greater than 50%,the chloride ion penetration coefficient of mortar girder increases rapidly with the increase of compression bending load.The chloride ion penetration coefficient of the girder decreases gradually along the vertical height under compression bending load.

关 键 词：再生砂浆 数字图像相关 压弯荷载 裂纹演变 氯离子扩散 

分 类 号：TU501[建筑科学—建筑技术科学]