Effect Of Design And Site Factors On Fatigue Cracking Of New Flexible Pavementsin The Ltpp Sps-1 Experiment

摘要

This paper presents the results of a study on the relative influence of design features and site factors on the fatigue performance of in-service flexible pavements. The data used in this study were from the SPS-1 experiment of the long-term performance pavement (LTPP) programme. This experiment was designed to investigate the effects of hot mix asphalt (HMA) surface layer thickness, base type, base thickness and drainage on the performance of new flexible pavements constructed in different site conditions (subgrade type and climate). Various statistical analyses (ANOVA, logistic regression, discriminant analysis) were adopted for data analyses. Among the design factors, base type was found to be the most critical factor affecting fatigue cracking. The best performance was shown by pavement sections with asphalt treated base (ATB). This effect should be interpreted in light of the fact that an ATB effectively means a thicker HMA layer. The combination of drainage and base type also played an important role in improving fatigue performance. Base thickness had a negligible effect while climatic conditions were found to have a significant effect with more fatigue-cracking occurrence in wet-freeze environment. Also, in general, pavements built on fine-grained soils showed the worst performance. Most of the findings from this study support the existing understanding of pavement fatigue performance. Yet, the analyses of data from in-service pavements in this study provide an overview of the interactions between design and site factors and provide new insights on various design options to achieve better long-term pavement performance.