【摘要】 对4组配合比的混凝土试件进行多向劈拉试验.利用数字散斑分析技术对其多向劈拉下的微裂纹扩展规律进行分析研究,建立损伤参量——微裂纹损伤面积ω和弹性模量损伤变量DE;同时进行混凝土试件劈拉前后的饱盐混凝土电导率法(NEL法)氯离子渗透性试验,探讨微裂纹损伤场对混凝土氯离子渗透性的影响.结果表明:微裂纹损伤对低水胶比混凝土的渗透性影响更大;随着弹性模损伤变量DE值的增加,氯离子扩散系数变化率β呈现线性递增的趋势,并近似拟合得到二者的关系式;水泥浆的强度、骨料的级配、孔隙率的大小以及损失场的确定等因素都会对氯离子渗透性能产生影响.更多还原

【Abstract】 Four groups of concrete specimens of different dimension were splitted in the test.The displacements of the concrete specimen surface were analyzed through DSCM(digital speckle correlation method).Furthermore,damage parameters,damage area based on the MCOD(micro-crack opening displacement)and damage variable DE based on the weighting-damping elastic modulus,were determined.At the same time,Cl-permeation of concrete specimens before and after the splitting test were all studied by NEL method,and the influences of micro-crack damage on the Cl-permeability were discussed.The test results show that there are more affection for micro-crack damage on the concrete permeation in the low waterbinder ratio of concrete than the high ones;there is a increasing relationship between damage variable DE based on the damping elastic modulus and change rate of Cl-diffusion coefficients;strength of cement paste,different aggregate gradation,varied porosity,uncertain damage area and so on have significant impacts on Cl-permeability of concrete.更多还原