Investigating the effect of cement-stabilized reclaimed asphalt pavement (RAP) materials on the mechanical behavior of granular subbase layers

In place of natural aggregate, the use of reclaimed asphalt pavement (RAP) has become usual in the road construction industry. For a while, it has been regarded as one of the sources for producing unbound subbase aggregate for pavement systems. Performance testing on RAP, RAP combined with virgin aggregate (VA), and RAP-VA mixed with a stabilizing agent has been the subject of many prior research initiatives. Nevertheless, the findings of different studies differ greatly from one another, and there are no precise recommendations for the optimal ratio of RAP to VA. As a result, the mixes in this research have been graded such that there will be minimal variability. In a full-factorial laboratory experiment, mixes including 0–80% RAP with 1, 2, 3, and 4% of Portland cement were assessed. The present study examined the effects of varying RAP amounts and cement as stabilizing agents on multiple properties of unbound granular subbase materials, including the modified proctor compaction, California bearing ratio (CBR), unconfined compressive strength (UCS), repeated triaxial test, permanent deformation, hydraulic conductivity, and shear strength characteristics. Based on the findings from the experiment, the RAP component had a substantial impact on the characteristics of the RAP mixtures along with the cement amount. By analysing the experimental tests, it was concluded that 80% RAP combined with 4% cement may be used as road subbase material.