炭黑与钢纤维对混凝土裂缝自监测性能的影响
Effect of carbon black and steel fibers on the concrete crack self-monitoring performance
丁一宁 1晏楚 2柳根金 3谢昊威 2宋世德2
作者信息
- 1. 广西大学 土木建筑工程学院,广西 南宁 530004
- 2. 大连理工大学 海岸与近海工程国家重点实验室,辽宁 大连 116024
- 3. 浙大宁波理工学院 土木建筑工程学院,浙江 宁波 315100
- 折叠
摘要
为了研究导电相对混凝土裂缝自监测性能的影响,本文对复掺炭黑-钢纤维的智能混凝土进行了试验研究.基于四电极法,对试件在弯曲荷载作用下的电阻变化率进行了分析,对比研究了不同钢纤维掺量对试件抗弯性能、裂缝自监测性能的影响.试验表明:结构型钢纤维的掺入能够显著提高试件开裂后的抗弯性能.基于荷载-时间-电阻变化率(load-time-FCR)曲线,可实现对混凝土试件开裂时刻的实时自监测.根据试验得到的电阻变化率-裂缝扩展位移(FCR-COD)曲线,FCR随着COD的增加而增加,并且曲线的斜率逐渐减小,使用对数函数能较好拟合FCR-COD关系曲线;裂缝监测灵敏度(gauge factor G)-裂缝扩展位移(G-COD)曲线中,随着钢纤维掺量的增加,相同COD下G值逐渐减小并且减小的幅度逐渐降低;结合导电机理并且使用COMSOL软件对试件裂缝自监测性能进行了分析.
Abstract
In this paper,an experimental study was conducted on smart concrete mixed with carbon black(CB)and steel fibers(SF)to study the influence of conductivity on the self-monitoring performance of concrete cracks.We used the four-probe method to analyze the fractional change in resistance(FCR)of the specimen under bending load,after which we investigated the effect of different steel fiber contents on flexural performance and self-monitoring performance.Results revealed that the flexural performance of specimens was significantly improved with the addition of structural steel fibers.The time of the occurrence of a crack in specimens can be monitored in real time according to the load-fractional change in the resistance-time(Load-FCR-Time)curve.On the basis of the FCR-crack propagation displacement(FCR-COD)curve obtained from the experiment,it was observed that FCR increased with the increase of COD,the slope of the curve gradually decreased in the FCR-COD curve,and the logarithmic function fitted well with the FCR-COD curve.In the Gauge factor-COD(G-COD)curve,the value of G decreased gradually with the increase of steel fiber content.Similarly,the reduction amplitude decreased gradually under the same COD.Finally,the smart concrete self-monitoring performance was analyzed based on the conductive mechanism and the software COMSOL.
关键词
钢纤维/智能混凝土/电阻变化率/裂缝自监测/灵敏度系数/数值模拟/纤维混凝土/炭黑Key words
steel fiber/smart concrete/fractional change in resistance/crack self-monitoring/sensitivity coefficient/numerical simulation/concrete with fibers/carbon black引用本文复制引用
基金项目
浙江省自然科学基金(LQ22E080024)
出版年
2023
国家科技期刊平台
NSTL
维普
万方数据