摘要
为探究玄武岩纤维对高强混凝土基本性能的影响,设置0%,0.15%,0.30%,0.45%和0.6%共5种纤维体积掺量,以抗压强度、劈裂抗拉强度、电通量、收缩率等作为表征参数,分析不同纤维掺量对高强混凝土基本性能的影响,并基于“经典建研模型”建立玄武岩纤维混凝土早龄期收缩模型。结合SEM扫描电镜从微观结构层面分析玄武岩纤维对混凝土的作用机理。研究结果表明:随着玄武岩纤维掺量的增大,抗压和劈裂抗拉强度呈现出先上升后下降的趋势,在纤维掺量为0.3%时同时达到峰值,分别提高了5.2%和17.3%。电通量和收缩率则随着纤维掺量增多一直降低,纤维掺量为0.6%时效果最佳;玄武岩纤维对混凝土收缩抑制效果明显,32 d龄期纤维掺量为0.6%时混凝土收缩率降低22.6%,且玄武岩纤维对混凝土早期收缩抑制效果优于后期,同时早龄期收缩模型计算精度系数较高。结合试验结果和电镜扫描可知,适量玄武岩纤维产生桥联作用及环箍效应,抑制裂缝的开展,能够提升混凝土抗压及劈裂抗拉强度。此外玄武岩纤维具有一定蓄水效果,能够有效改善混凝土界面过渡区,降低连通孔隙率,从而抑制混凝土收缩。
In order to explore the influence of basalt fiber on the basic properties of high-strength concrete,five fiber volume dosages of 0%,0.15%,0.30%,0.45%,and 0.6%were set,and the compressive strength,splitting tensile strength,electric flux,shrinkage,etc.were used as characterization methods for analyzing the effect of different fiber contents on the basic properties of high-strength concrete.Then,on the basis of considering the influence of basalt fiber on shrinkage,a model of early age shrinkage of basalt fiber concrete was established based on the“classical research model”.The improvement mechanism of basalt fiber on concrete was analyzed from the microstructure level with SEM scanning electron microscope.The results show that with the increase of the basalt fiber content,the compressive and split tensile strength values show a trend of increasing first and then decreasing,reaching the peak at the same time when the fiber content is 0.3%.Compressive and split tensile strength increased by 5.2%and 17.3%,respectively.The electric flux and shrinkage rate decrease as the fiber content increases,and the effect is best when the fiber content is 0.6%.Basalt fiber has an obvious inhibitory effect on concrete shrinkage,and The shrinkage rate is reduced by 22.6%when the content of 0.6%is added for 32d.It’s early-stage shrinkage-inhibition effect is better than that in the later stage.Combining the test results and scanning electron microscopy,it can be seen that a proper content of basalt fiber produces bridging effect and hoop effect,inhibits the development of cracks,and can improve the compressive and split tensile strength of concrete.In addition,basalt fiber has a certain water storage effect,which can effectively improve the Interfacial Transition Zone,reduce the connected porosity,and thereby inhibit the shrinkage of the concrete.
作者
李福海
高浩
唐慧琪
姜怡林
占玉林
沈东
LI Fuhai;GAO Hao;TANG Huiqi;JIANG Yilin;ZHAN Yulin;SHEN Dong(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Wenzhou Qidu Bridge North Branch Bridge Construction Co.,Ltd.,Wenzhou 325099,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第2期419-427,共9页
Journal of Railway Science and Engineering
基金
四川省中央引导地方科技发展专项(2020ZYD011)
国家自然科学基金资助项目(U2034205)。
关键词
玄武岩纤维
力学性能
电通量
SEM
收缩模型
basalt fiber
mechanical properties
electric flux
SEM
shrinkage model
