The objective of the presented investigation was to verify findings that moisture has a negative effect on the bond force leading to a reduction of the mean maximum shear force up to 30% for long term water storage or combined pressure and short term water storage at 40°C. Additionally, the influence on maximum shear stiffness was investigated. Furthermore, it was assumed that the reduction of shear properties would increase with higher applied temperature. The investigation was conducted using different up to date pavement structures for urban roads and heavy trafficked motorways. The chosen material represents the actual Swiss construction practice favoring relatively open graded low noise surface courses. Testing was done using the Layer-Parallel Direct Shear device (LPDS) and the Shear Box as an additional measure for the shear properties. The results showed that 72h water conditioning at 40°C reduces interlayer shear strength by 2% to 20%. 72h water conditioning at 60°C is more severe, reducing strength by 15% to 25% and stiffness by 14% to 30%.

Additional Metadata
Keywords Interlayer shear bond, Moisture damage
Journal International Journal of Pavement Research and Technology
Raab, C. (Christiane), Partl, M.N. (Manfred N.), & Halim, A.O. (2012). Experimental investigations of moisture damage in asphalt. International Journal of Pavement Research and Technology, 5(3), 133–141.