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Reclaimed Asphalt pavement (RAP) is a C&D waste originating from the reclamation of asphalt pavement which has completed its service life. Using RAP would potentially reduce reliance on primary aggregates and lowers the environmental impact of construction. The present study is an attempt made to utilize RAP judiciously as a bound base course of the flexible pavement. Natural coarse aggregates were replaced by RAP in proportions of 50% & 100% with & without Warm Mix Asphalt (WMA), for production of bound-base course mixes. To ensure the long run performance, the aging condition was simulated in the laboratory and mechanical properties such as Marshall Stability, Tensile Strengths, Marshall Stability Retained, Indirect Tensile Ratio, rutting resistance, Fatigue life, and abrasion resistance were considered. With the incorporation of 50-100% coarse RAP, the Marshall Stability, rutting resistance and abrasion were found to be improved by 30-32%, 43-104% and 11-17% respectively. Similarly, total cost saving is about 15-35%, which is quite significant. However, the addition of WMA enhanced the cost by 3-4%, which is insignificant when combined with RAP, furthermore, the reductions in fume emission enhance the sustainability aspect of the technology.

Scarcity of natural aggregates and illegal dumping of wastes originating from roads and industries are the major challenges for a developing country. The present study is an effort to provide a sustainable solution to the aforementioned challenges by utilizing these wastes for production of subbase course of concrete pavements. In the study, the optimum proportion of reclaimed asphalt pavement (RAP) along with the optimum proportion of the various supplementary cementitious admixtures (SCM) such as flyash (FA), silica fume (SF) and sugarcane bagasse ash (BA) have been evaluated for productions of dry lean concrete (DLC) mixes. The effect of the higher amount of Portland cement on the properties of RAP inclusive DLC mixes was also investigated. It was observed that the hardened properties of DLC containing RAP are mostly depended upon the maximum dry density of the fresh mixtures. Inclusions of considered industrial waste, as part replacement of Portland cement, were found to have an insignificant effect, whereas, when included in excess of cement, enhanced the properties of RAP-DLC blends significantly. The results of the study depicted that the suitability of RAP aggregates for DLC subbase may be increased by increasing the cement content by about 50%, whereas, for achieving the comparable performance to that of DLC containing natural aggregates, the quantity of cement shall be doubled. Based on the results of different parts of the study, it is recommended to include at least 30% extra cement content with either of 10% SF or 20% FA for sustainable DLC mixtures containing 75% coarse RAP aggregates.

Mechanical foaming of bitumen is a popular technique employed to reduce the viscosity of binder for ensuring coating of aggregates at lower temperature. The potential of this technique is b...

The present study investigates the potential of RAP for various layers of flexible and concrete pavements. Natural aggregates were replaced in different proportions by the coarse RAP and fine RAP, ...

In the present study, the suitability of coarse (C) and fine (F) RAP aggregates extracted from two flexible pavements (OLD (O) & NEW (N)) having different service (20 yrs. & 2½ yrs.) and stockpiling life (8 months & 0 months) for productions of Dry Lean Concrete (DLC) and bituminous mixtures is assessed. For the same, a total of 15 DLC mixes were cast, consisting of 9 mixes containing different proportions (25–100%) of CO and CN aggregates and 6 mixes containing FO (25–100%) and FN aggregates (25% and 50%). The effect of both fractions of RAP on optimum moisture content (OMC), maximum dry density (MDD), compressive strength, water absorption and permeable voids were studied. Volumetric properties of compacted bituminous mixes containing aggregates milled from new pavement were also investigated. It was found that aggregates obtained from old pavement have the potential to replace 75% coarse and 50% fine natural aggregates whereas 25% CN and zero FN aggregates may be utilized for DLC mixes. Contrary, aggregates obtained from new pavement were found to be suitable for construction of base and wearing course of flexible pavements whereas aggregates from older pavement could not be even molded while preparing test sample due to loss of binding properties of asphalt mixtures by virtue of oxidation process.