Experimental study on the pore structure variation of self-compacting rubberised concrete under fatigue load

In this paper, the correlation analysis between mechanical fatigue properties and pore structure was performed on the self-compacting rubberised concrete (SCRC). Four-point bending destructive and non-destructive fatigue tests were conducted for obtaining mechanical properties of the SCRC, while the mercury intrusion porosimetry (MIP) test was applied to the pore structure analysis. Several parameters were utilised for the description of pore structure, including porosity, mean pore diameter, threshold, fractal dimension, actual minimum diameter and the most probable pore diameter. The Pearson formula was introduced for the study on the correlation among the fatigue life, the fatigue damage and different pore structure parameters. The experimental results show that the fatigue load has a strong effect on the pore structure change. As the damage developing, the pore structure of the SCRC deteriorated: the porosity, the mean pore diameter, the actual minimum diameter and the most probable pore diameter increase. Meanwhile, the capillary pore fractural dimension decreases slightly. On the basis of the factors, the parameters of pore structure can be served as indices for the fatigue life prediction. The correlation parameters between the fatigue life and the optimal parameters of pore structure (the porosity, the most probable pore diameter, the mean pore diameter and the mesopore fractural dimension) have been determined in this paper.