废弃纤维再生混凝土孔结构及碳化性能分形特征研究

以水灰比、再生骨料取代率、废弃纤维长度和体积掺量为设计变量,利用压汞试验及快速碳化试验,探讨了废弃纤维再生混凝土的孔结构、碳化性能的分形特征以及两者之间的关系.结果表明:废弃纤维再生混凝土孔结构具有显著的分形特征,废弃纤维的加入可阻止结构中有害孔的形成,改善废弃纤维再生混凝土内部的孔结构;纤维的加入可以提高再生混凝土的碳化性能,最优体积掺量为0.12%,碳化边界轮廓线的分形维数越小,对应的碳化深度越大;废弃纤维再生混凝土的碳化深度与孔隙体积分形维数之间存在相关性,随着孔体积分形维数减小碳化深度增大,根据孔隙体积分形维数来评价不同设计变量的废弃纤维再生混凝土碳化深度是可行的.

Pore Structure and Carbonation Fractal Characteristics of Waste Fiber Recycled Concrete

The design variables of the experiment were water cement ratio, recycled aggregate replacement ratio, waste fiber length and volume content.The fractal characteristics of pore structure and carbonation performance of waste fiber recycled concrete were investigated by mercury injection test and rapid carbonation test.The results indicate that waste fiber recycled concrete pore structure has a prominent fractal characteristic, the addition of waste fiber can prevent the formation of harmful pore structure, and improve the waste fiber recycled concrete pore structure inside.The waste fiber can improve the carbonation resistance of recycled concrete and the optimal volume content is 0.12%, the smaller fractal dimension of the carbide boundary contour, the greater carbonation depth.There is a correlation between the depth of carbonation and pore volume fractal dimension of recycled concrete waste fiber.As the pore volume fractal dimension decreases and carbonation depth increases, it is feasible to evaluate different design variables of waste fiber recycled concrete carbonation depth according to the pore volume fractal dimension.