Expansion and contraction of clogged open graded friction course exposed to freeze-thaw cycles and degradation of mechanical performance

OGFC specimens with five air void contents and two clogging levels were scanned using X-ray computed tomography (CT). The contents of total and connected voids before and after clogging were calculated based on the reconstructed three-dimensional (3D) microstructure. The expansion and contraction of unclogged and clogged OGFC during eight freeze-thaw (FT) cycles were measured using a self-developed drainage instrument. Cantabro test and uniaxial compressive strength test were conducted on OGFC specimens before and after FT cycles. Results show that the expansion of OGFC during freezing is larger than the following contraction due to ice melting, which cause the residual expansion deformation in each FT cycle. OGFC has significant mass loss in the Cantabro test and reduction in compressive strength after FT cycles. The accumulated residual deformation and mechanical degradation after FT cycles increase with the increase of void content and clogging level.