Proposed SDI equations to improve the effectiveness in evaluating crack damage on the road pavement

Abstract

Road pavement has a life-cycle, where the age of the road pavement starts from design to the end of service life, so that maintenance works are one of the most important stages. To enable carrying out maintenance works, a process of assessment of road conditions, both from structural and functional, is required. At present, one of the evaluations of the functional condition of the road is using surface distress index/SDI. The SDI method used today has a simple procedure and is easy to use. However, in the term of accuracy in estimating the functional condition, it will be seen that the SDI parameter is far from satisfying. In this study, an effort to increase the effectiveness of SDI parameters especially for crack damage was carried out. The improvement of SDI parameter was conducted by developing a non-linear equation for each type of crack damage based on the deduct value curve of the PCI method, with a coefficient of determination R2 of at least 0.99. The proposed SDI equations have been calibrated and produced an error less than 6.2%. A comparison between the value of the proposed and the existing SDI also was presented and the results showed that the similarities between the two SDI values were only 19.86%. The rest of the existing SDI value was under-estimate proposed SDI, but there was also an existing SDI value over-estimated proposed SDI, especially in the road segment which was only found one type of crack damage with low/medium severity and low density.