低硅灰水泥砂浆孔隙结构及分形维数的演变特征

Evolution of pore structure and fractal dimension of silica fume cement mortar

采用压汞法对不同硅灰掺量水泥砂浆孔隙结构进行测定,引入分形理论,对孔径分布进行定量表征,分析孔隙结构随硅灰掺量和养护龄期的演变规律。结果显示:掺入硅灰使得砂浆孔结构在各龄期均比基准砂浆复杂,并且掺硅灰砂浆的孔表面积分形维数均高于基准砂浆。当掺量为5%和8%时,砂浆孔径分布形态相似;当掺量为10%时,孔径分布形态存在明显差异。分形维数定量反应了孔隙结构的演变规律,与观察孔径分布曲线得出的结论相一致。

The pore structure of cement mortar with different silica fume content was determined by mercury injection method.Fractal theory was introduced to quantitatively characterize pore diameter distribution and analyze the evolution law of pore structure with silica fume content and curing age.The results show that the pore structure of mortar mixed with silica fume is more complex than that of reference mortar at all ages,and the integral shape dimension of pore surface mixed with silica fume mortar is higher than that of reference mortar.When the mixing amount is 5% and 8%,the pore diameter distribution of mortar is similar.When the dosage is 10%,the pore size distribution has obvious difference.The fractal dimension reflects the evolution law of pore structure quantitatively,which is consistent with the conclusion obtained by observing the pore diameter distribution curve.