ENHANCEMENT OF UNCONFINED COMPRESSIVE STRENGTH (UCS) VALUES OF RECLAIMED ASPHALT PAVEMENT (RAP) FOR USING IT AS SUBBASE / BASE COURSE OF FLEXIBLE PAVEMENT (Paper 635)

Reclaimed Asphalt Pavement (RAP) materials are generally obtained during rehabilitation, strengthening and upgradation of existing flexible pavement. Generally high quality RAP materials having uniform properties are intended to use for preparation of Hot Mix Asphalt (HMA). However, RAP materials which are not suitable for reusing in the preparation of HMA are generally intended to use in Subbase / Base course of flexible pavement. The present study is to assess the suitability of using RAP materials obtained from milling / full depth rehabilitation of existing flexible pavement as potential subbase / base course for new flexible pavement construction. As per Indian Road Congress (IRC) recommendation, unconfined compressive strength (UCS) value of treated aggregates shall be in the range of 1.50 Mpa-3Mpa and 4.50 Mpa -7Mpa for its use as subbase and base of flexible pavement respectively. It is observed from the present study that though UCS values of 100% RAP is very low (55kpa), it is increased upto 4 Mpa when mixed with suitable proportion of Crushed stone aggregates and stabilizing with various percentages of cement thereby making it suitable for its use as subbase / base course of flexible pavement. Modified proctor compaction tests were conducted on both RAP and mixture of RAP and crushed stone aggregates to established optimum moisture content (OMC) for the preparation of UCS samples. Similarly grain size analysis was also done for RAP and mixture of RAP with crushed stone aggregates.