基于CT扫描的环氧树脂基混凝土裂缝观测与冲击损伤演化研究

环氧树脂基混凝土是一种新型路面铺装材料。本文估算了道路使用过程发生"跳车"现象时货车车轮对路面产生的冲击荷载,根据计算结果,利用落锤冲击试验机对含有不同程度初始损伤的环氧树脂基混凝土试件进行多次冲击试验,研究其冲击疲劳现象。为了准确描述环氧树脂基混凝土的初始损伤,采用CT(计算机断层)扫描技术重构了试件的立体图像,对其中的内部裂缝进行了统计,建立了初始损伤裂缝体积占试件体积的百分比与基于材料弹性模量衰减的损伤变量之间的关系。通过追踪经受一定次数冲击后试件的弹性模量,分析了不同程度初始损伤下环氧树脂基混凝土的冲击损伤随冲击次数的变化规律;结合多次冲击荷载下环氧树脂基混凝土弹性模量的衰减,研究了初始损伤对环氧树脂基混凝土冲击疲劳过程中损伤演化规律的影响。

On the Crack Observation and Impact Damage Evolution of Epoxy Polymer Matrix Concrete Based on CT Scanning

Epoxy polymer matrix concrete is a new pavement material.In this paper,the impact load of freight car wheels on road surface due to “vehicle jumping” phenomenon was estimated during road use process.Based on calculation results,impact experiment of epoxy resin matrix concrete specimens with different initial damages was carried out based on drop hammer impact testing machine,to study its impact fatigue behavior.In order to accurately describe the initial damage of epoxy resin matrix concrete,stereo image of specimen was reconstructed by CT (Computerized tomography) scanning technique.The internal cracks were counted.Then,the relation between the percentage of initial damage cracks volume to whole specimen volume and the damage variables,which is based on the attenuation of material's elastic modulus,was established.By tracking the modulus of elasticity of specimens after a certain number of shocks,the impact damage variation mode of epoxy resin matrix concrete with different degrees of initial damage and subjected to certain impact times was analyzed.Combining the attenuation of elastic modulus of epoxy resin matrix concrete after multi times impact loading,the influence of initial damage on the damage evolution of epoxy resin matrix concrete during impact fatigue process was investigated.