I. Highway Planning, Management, Performance Evaluation & Instrumentation


1. Bituminous Bound Macadam for Strengthening of Existing Pavements on National Highway Works

May 2002 to May 2005
Maharashtra Engineering Research Institute, Nasik (R)


Present Status and Progress

The test track on Mumbai –Konkan – Goa Road (N.H.17), Km. 302/600 to 306/00, have been constructed under this scheme. The construction of test track was completed in May 2002.

The test track has been constructed during April 2002 to May 2002. Length of test section selected between Km 302/600 and 306/0 is about 2.37 Km. One km length (km 304/0 to 305/0) is constructed using Bituminous Bound Macadam (BBM) and the remaining length of 1.37 Km was constructed by using BUSG as per MOSRTH guidelines. For comparison of test tracks with two different specifications, pre-monsoon and post-monsoon observations have been recorded for the last three years. Roughness index and visual observations of the test track are also taken. From the observations data, the performance of test track seems to be ‘Very good’ up-till now.
It is observed that performance of test track having bituminous bound macadam (BBM) layer is excellent. Bituminous Bound Macadam (BBM) treatment is time saving as compared to Built Up Spray Grout (BUSG) and can be used for new work as well as for strengthening of existing road. Built Up Spray Grout (BUSG) can be used only in new work. The riding quality of Built Up Spray Grout (BUSG) and bituminous bound macadam (BBM) is found to be almost similar as per the data recorded by Automatic Road Unevenness Recorder (ARUR). The construction of Bituminous Bound Macadam (BBM) involves 40 mm hand broken metal and thus lead of material transportation is minimized. There is a cost saving of at least 20% for BBM treatment as compared to BUSG treatment indicating BBM treatment to be more economical than BUSG. In view of three years observations, It has been concluded that BBM can be suitably used as a substitute to BUSG on various National Highways in Maharashtra State.
Final reports have been circulated to Regional Chief Engineers in Maharashtra State for their study and information