A novel approach to assess internal pore structure and quantify tortuosity of clogged pervious concrete through image analysis techniques

The major objective of this research was to develop an innovative approach to characterise the pore structure of pervious concrete (PC) mixtures and quantify tortuosity in pre- and post-clogged conditions through 2D and 3D image analysis. Four different types of PC mixtures were prepared and subjected to computed tomography (CT) scanning to retrieve morphological information covering over 1900 images, followed by tortuosity quantification of each of 200 interconnected pore paths using vascular modelling toolkit (VMTK). The porosity of PC obtained from laboratory-based tests was 10–25% lower than image analyses. Further, along the depth of PC, a significant decrease in the number of pores in the top 60–80 mm was observed due to clogging, which revealed that maintenance be adopted only in the top 80 mm. Control and clogged PC with smaller sized aggregates and lower w/c ratio were more tortuous compared to higher w/c ratio while opposite for larger sized aggregates, ascribed to the occurrence of shorter interconnected pore paths comprising larger pore diameter, remarking that permeability will depend on both tortuosity and path diameter. CT scanning was used in predicting tortuosity and pore interconnectivity of PC through VMTK approach extensively used in medical science and seldom used in engineering.