Performance Evaluation of Gravel Road Sections Sealed Using Open Graded Premix Surfacing with Bitumen and Bitumen Emulsion as the Binders

In developing countries like India, rural areas lack adequate transportation facilities. The Ministry of Rural Development (MoRD), Government of India (GoI) decided to develop rural roads under Pradhan Mantri Gram Sadak Yojana (PMGSY). The objective of this program is to achieve connectivity to all habitations under different climatic conditions. There are certain disadvantages associated with construction of the rural roads using gravel like dust generation, gravel loss over a period of time due to passage of vehicles and inaccessibility during rains. The best solution to reduce these problems is to seal the gravel roads instead of maintaining it, since many studies showed that the maintenance of unsealed road is more costly than the sealed road over a period of time. Hence, a project has been taken up to give full and all weather connectivity using locally available materials. Up to the surface course, the selected road was constructed using the locally available gravel. Many sealing techniques are available, out of which, open graded premix surfacing (OGPS) was opted in this study. This paper aims at studying the performance evaluation of gravel surface sealed with OGPS. The variables considered in this study are: gravel surface type, primer rate, and binder type. Past researchers found that the roughness, skid resistance and texture depth significantly affect the performance of sealed gravel roads and these three parameters are considered as performance indicators in this study. Eight sets of data were collected at regular intervals starting from November 2013 to March 2015. The surface distresses were also measured. From the analysis it was observed that the roughness on emulsion based OGPS was more when compared to bitumen based OGPS. Emulsion based OGPS resulted in less texture depth when compared to bitumen based OGPS. Skid resistance varied differently with respect to the binder type, type of surface course and priming rate. Even though there is little effect of gravel surface course type on roughness and texture depth, the effect of primer rate on roughness, texture depth, and skid resistance is negligible.