A Study on Permeability Characteristics of Asphalt Pavements (original) (raw)

Ingress of moisture during early pavement life leads to undue deflection, increase of pore pressure under traffic, stripping of bitumen from aggregate and ultimately, reduction in strength. It is important to evaluate the sensitivity of asphalt mixes to the ingress of water, which can be quantified in terms of permeability (or hydraulic conductivity). The primary objective of the present study was to characterise permeability of a newly laid asphalt pavement through field-based and laboratory-based measurements. Field permeability of a newly laid pavement was measured at different sections in longitudinal as well as transverse directions. Cores were extracted from the locations where field permeability tests were conducted. Loose mixtures were also collected from plant and were compacted in laboratory to different air void contents through variable compactive effort. Permeability of field cores and laboratory compacted mixtures was determined in laboratory. Results indicated significant differences in field and laboratory permeability values. Field permeability showed a strong positive correlation with laboratory determined permeability of cores and compacted samples. Transverse variation of permeability was also found to be quite significant. All measured permeability values had a positive correlation with air voids. Statistical modelling of permeability-air void data was also attempted.