热损伤下玄武岩纤维混凝土孔隙分形特征及力学特性试验研究  

Experimental study on pore fractal characteristics and mechanical properties of basalt fiber concrete under thermal damage

作　　者：王靖 何刚 王文飞 WANG Jing;HE Gang;WANG Wenfei(Zhengzhou City Vocational College,Zhengzhou 452370,China;State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China;CCCC First Highway Consultants Co.,Ltd.,Xi′an 710075,China)

机构地区：[1]郑州城市职业学院,河南郑州452370 [2]武汉理工大学硅酸盐建筑材料国家重点实验室,湖北武汉430070 [3]中交第一公路勘察设计研究院有限公司,陕西西安710075

出　　处：《混凝土》2024年第9期124-128,共5页Concrete

基　　金：国家自然科学基金(51978544)。

摘　　要：基于试验研究不同温度损伤下玄武岩纤维混凝土内部孔隙结构及力学性能变化规律,利用自加热核磁共振仪(NMR)及电液伺服压力机测量50℃、100℃、200℃、300℃温度下玄武岩纤维混凝土孔隙结构及力学性能,并结合电镜扫描仪(SEM)观测高温后试件内部微观结构。结果表明:试件T2光谱具有明显的三峰特征,温度的升高使其T2光谱峰值、孔隙率升高,温度从50℃逐渐升高到300℃时试件平均孔隙率由2.63%增至4.16%,孔隙结构分形维数随之降低,且D_(NMR)(min)变化幅度明显低于D_(NMR)(max),大孔隙的复杂性更容易受到热损伤下温度的影响。相较于50℃时试件强度,100℃、200℃、300℃时试样单轴抗压强度降幅为4.81%、16.53%、24.90%,抗拉强度降幅为8.51%、25.53%、42.55%,温度的升高使得试件孔隙度增大,抵抗外荷载能力减小,整体性降低。SEM试验结果表明高温后试件内部存在大量裂隙,且随着温度的升高试件内部裂纹宽度变大,数目明显增多。Based on the experimental study of the internal pore structure and mechanical properties of basalt fiber concrete under different temperature damage.The pore structure and mechanical properties of basalt fiber concrete at 50℃,100℃,200℃C and300℃were measured by self heating nuclear magnetic resonance(NMR)and electro-hydraulic servo press.The microstructure of the specimen after high temperature was observed by SEM.The results show that the T2 spectrum of the specimen has obvious three peak characteristics and the increase of temperature increases the T2 spectrum peak and porosity.When the temperature gradually rises from 50 C to 300℃,the average porosity of the specimen increases from 2.63%to 4.16%,and the fractal dimension of the pore structure decreases accordingly,and the variation range of D_(nmr)(min)is significantly lower than De(max).The complexity of macropores is more susceptible to the temperature under thermal damage.Compared with the strength of the specimen at 50 C,the uniaxial compressive strength of the coal samples at 100 C,200℃and 300℃decreasesby 4.81%,16.53%and 24.90%,and thetensilestrengthdecreasesby 8.51%,25.53%and 42.55%.The increase of temperature increases the porosity of the specimen,reduces the resistance to external load and reduces the integrity.SEM test results show that there are a lot of cracks in the specimen after high temperature,and with the increase of temperature,the width and number of cracks in the specimen become larger.

关 键 词：玄武岩纤维混凝土 核磁共振 T_(2)光谱 孔隙率 分形维数 力学性能 微观结构 

分 类 号：TU528.041[建筑科学—建筑技术科学]