Cracks in porous European mixes: A theoretical and experimental study

As is well known, cracking in pavements occurs when a stress is built up in a surface layer that exceeds the tensile or shear strength of the pavement and may be associated with various distress mechanisms. In the case of fatigue cracking, phenomena can be the result of repetitive traffic loads or high deflections, for example, due to the underlying layers defects. On the other hand, it is well known that Porous European Mixes (PEMs) do not seal the underlying pavement against moisture intrusion and this fact can increase the potential for stripping of both the surface and underlying layers (especially when the underlying binder course, BIC, has high void contents). In the light of the above-mentioned facts, the purpose of this study is the analysis of the bottom-up cracking associated with stripping in underlying layers and the evaluation of the effectiveness of laboratory testing in predicting premature failure. A case-history is described. Analyses show the synergetic importance of the system BIC & PEM. Recommendations are proposed in order to minimize the risk of such premature failures in Porous European Mixes.