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In recent times, reclaimed asphalt pavement (RAP) has gained popularity among researchers for its low-impact development abilities and socioeconomic factors. But its application in modern construction is still restricted to 10%–30% due to the heterogeneous behavior of the resulting mixtures. The current study investigated the possibilities of increasing RAP integration for foam-mix asphalt synthesis with alternative mineral fillers derived from industrial and agricultural waste—namely, fly ash and sugarcane ash, respectively. To assess the influence of RAP and other fillers on the structural and functional parameters of foam-mix asphalt such as indirect tensile strength, resilient modulus, rutting resistance, abrasion resistance, and Marshall stability were measured. The study indicated that the addition of sugarcane ash and fly ash improves the indirect tensile strength of the foam mixtures. Furthermore, fly ash has better performance than sugarcane ash in terms of tensile strength; however, the reverse trend was found for abrasion and rutting resistance. Lastly, CO2 emissions for the designed mixtures were evaluated using emission factors, which showed that the lower-temperature mixes have lower emission rates than higher-temperature mixes, primarily due to the energy involved in heating bitumen for foam-asphalt mixtures. [ABSTRACT FROM AUTHOR]

The paper aims to address the use of natrojarosite, an industrial waste material, as a partial replacement to portland cement in roller-compacted concrete pavement (RCCP) mixtures. Natrojarosite particles were used in proportions of 0%, 5%, 15%, 20%, and 25%, by weight of cement, respectively. It was observed that the optimum moisture content increases as the natrojarosite replacement level increases but were still lower than that of the control mixture. Meanwhile, the maximum dry density was found to be enhanced until 15% of natrojarosite replacement level, and subsequently, the strength and transport properties were also found to be improved. Scanning electron microscope images confirmed that the natrojarosite particles acted as a filler material which improved the transition zone and pore structure of the hydrated matrix. Contrarily, higher replacement levels showed reduction in the concrete strength and higher susceptibility to acid attack primarily due to the high sulfur trioxide content in the natrojarosite particles. Nevertheless, natrojarosite of up to 15% could be used to improve the strength and durability of RCCP. Moreover, the use of natrojarosite particles would lower the consumption of portland cement and eliminate the disposal issue of the harmful natrojarosite waste. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]