Freeze-thaw impacts on macropore structure of fiber-reinforced clay by industrial computed tomography scanning

ABSTRACT: In cold climates, freeze-thaw cycling is an important issue in engineering. In freeze cycles, translocation of water and ice can be caused by thermodynamic conditions at temperatures just below 0 degC, impacting the mechanical properties of soils. Major efforts across geotechnical studies have attempted to develop reinforcement methods to decrease the adverse effect of these cycles. Recent studies have shown that Polypropylene fibers can provide an effective method to increase soil strength. However, there are few macrostructural investigations available to demonstrate the underlying physical basis for this effectiveness. In this study, Computed tomography (CT) images were taken from clayey reinforced samples with the addition of 2% Polypropylene fibers that were subjected to a maximum of 10 closed-system freeze-thaw cycles (FTCs). The results show that the significant effects of FTCs on soil structure are the reduction of macropores and augmentation of mesopores, while the addition of Polypropylene fibers changes the reduction amount of macropores from 28% to 18% following 10 FTCs.