Study of Pore Fractal Characteristic of Cement Mortar

Pore structure of cement mortar was tested by mercury intrusion porosimetry(MIP) with different water-cement ratio at different age.Fractal model based on thermodynamic method was used in calculation of pore surface fractal dimension of cement mortar.The relationships between pore surface fractal dimensions and porosity,pore surface area,average pore diameter,median pore diameter and strength of mortar were studied.The results indicate that pore surface fractal dimension which is calculated by fractal model based on thermodynamic method can represent the complexity of pore structure very well,and pore surface fractal dimension has poor correlation with porosity but good correlation with pore surface area,average pore diameter,median pore diameter and strength.As pore surface fractal dimension increases,average pore diameter and median pore diameter of cement mortar decrease,and pore surface area and strength of mortar increase.Thus,pore surface fractal dimension that is calculated by fractal model based on thermodynamic method can be assumed as integrative evaluation index for evaluating the pore structure characteristic of cement mortar,and it has good correlation with mechanical performance of cement mortar.