I. Highway Planning, Management, Performance Evaluation & Instrumentation

3. PAVEMENT PERFORMANCE

A. COMPLETED PROJECTS
2. Use of Laterite Stones in W.B.M. Construction
Duration:

May 2001 to May 2005
Maharashtra Engineering Research Institute, Nashik (R)

 

Present Status and Progress

The test tracks on Kolambe – Kulay – Phasawale road (MDR-43) and Chapheri – Kasari road (MDR-36) in Ratnagiri District have been constructed from Km. 9/0 to 10/0 and Km. 0/0 to 1/0 respectively in May 2001. Final post construction observations have been taken in June 2005. Report has been prepared and sent to concerned P.W.D. Chief Engineer and Field Officers for information.

 
Findings /Supporting Data
The test track on Kolambe-Kulay-Phansawale Road, MDR-43 has been constructed from Km. 9/0 to 10/0 under this scheme. Final post construction observation of the test track has been taken in June 2005. From Km. 9/0 to 9/350, WBM with 100% trap metal of 40 mm size (100 mm loose) + 75mm BBM and 20 mm thick premix carpet with liquid seal coat involving black basalt stone metal chips are used for W.B.M. construction. From Km. 9/350 to 9/700, W.B.M. with 50% trap metal of 40 mm size with 50%, 80 mm laterite over size (100 mm loose) + 75 mm BBM and 20 mm thick premix carpet with liquid seal coat black basalt involving laterite stone metal chips are used in 50:50 proportion. For WBM on Chapheri-Kasari road km. 0/0 to 1/0, (80 mm size) laterite metal and 60 mm size laterite metal used in the W.B.M. and on this layer 75mm thick BBM and 20 mm premix carpet with liquid seal coat used as a wearing course. Post construction observations have been taken for three years (pre-monsoon and post-monsoon). Roughness Index and visual observations of the test track are also taken. From the observations data, the performance of the test track seems to be ‘good’ up-till now.
 
Limitations
Based on the post construction observations it can fairly be concluded that the above test track is giving good performance. The following conclusions have been drawn.
 
(i) Economical Lead
As laterite stones are abundantly available in Konkan Region it can be used for base and sub-base courses to minimize cost of transportation of materails.
 
(ii) Cost Saving
There is about 25 – 30% saving in material cost by using 100% laterite stone for W.B.M. construction as compared to the use of 100% trap metal.
 
(iii) Engineering Properties
The laterite stones have been found with sufficient mechanical strength and toughness to withstand at low and medium traffic of M.D.R. Roads. It can thus be suitably used as locally available material in W.B.M. construction.
BBM and premix carpet as wearing surface prevents disintegration of W.B.M. and produces surfaces with longer life.
 
Recommendations
Final reports are circulated to the concerned P.W.D. Chief Engineer for information