DEVELOPMENT AND PERFORMANCE EVALUATION OF INNOVATIVE PAVEMENT COMPOSITES INCORPORATING CONSTRUCTION INDUSTRY BY-PRODUCTS AND RECYCLED CONSTRUCTION AND DEMOLITION WASTE

The present study focused on the development and performance evaluation of innovative pavement composites incorporating recycled Construction and Demolition Waste (CDW) and construction industry by-products, namely Lime and Rice Husk Ash (RHA), for sustainable flexible pavement applications. Based on the laboratory investigations and performance evaluation, the following conclusions are drawn: 1.                The characterization of recycled CDW aggregates indicated that their physical and engineering properties satisfy the relevant requirements of IRC and MoRTH specifications, demonstrating their suitability for pavement construction. 2.                The incorporation of recycled CDW, Lime, and RHA significantly improved the engineering properties of the natural soil compared with the untreated control mix. 3.                The Maximum Dry Density (MDD) of the pavement composites increased with the addition of recycled CDW, while the Optimum Moisture Content (OMC) decreased, indicating improved compaction characteristics and better particle packing. 4.                The California Bearing Ratio (CBR) values increased considerably for all stabilized mixtures, confirming the enhanced load-bearing capacity of the pavement composites. The highest CBR value was obtained for the optimum mix, making it suitable for use in subgrade and sub-base layers of flexible pavements. 5.                The Unconfined Compressive Strength (UCS) increased progressively with curing time due to the pozzolanic reactions between Lime and Rice Husk Ash. The formation of cementitious compounds improved inter-particle bonding and resulted in higher compressive strength and stiffness. 6.                The combined use of Lime and Rice Husk Ash proved to be more effective than using recycled CDW alone, as the stabilizing agents enhanced strength development, reduced plasticity, and improved the overall durability of the pavement composites. 7.                Regression analysis established strong correlations among engineering parameters such as MDD, CBR, and UCS, indicating that the developed predictive models can be effectively used for estimating pavement material performance. 8.                Among the investigated mixtures, the pavement composite containing 50% recycled CDW, 4% Lime, and 6% Rice Husk Ash exhibited the best overall engineering performance in terms of compaction, bearing capacity, compressive strength, and durability. This mixture is identified as the optimum pavement composite for the materials considered in this study. 9.                The utilization of recycled CDW and construction industry by-products reduces the demand for natural aggregates, minimizes landfill disposal of construction waste, lowers environmental impacts, and contributes to sustainable resource management. 10.             The developed pavement composites offer an economical and environmentally friendly alternative to conventional pavement materials and are suitable for low- and medium-volume flexible pavement applications. 11.             The outcomes of this study support the principles of sustainable pavement engineering and circular economy by promoting the beneficial utilization of construction waste and industrial by-products in transportation infrastructure. Overall, the research demonstrates that innovative pavement composites incorporating recycled Construction and Demolition Waste, Lime, and Rice Husk Ash can achieve satisfactory engineering performance while reducing construction costs, conserving natural resources, and promoting sustainable road construction practices

[1] A. Arulrajah, M. M. Disfani, S. Horpibulsuk, C. Suksiripattanapong, and N. Prongmanee, "Physical properties and shear strength responses of recycled construction and demolition materials in pavement subbase applications," Construction and Building Materials, vol. 58, pp. 245–257, 2014. [2] A. Arulrajah, J. Piratheepan, M. Bo, and M. Sivakugan, "Geotechnical characteristics of recycled crushed brick blends for pavement sub-base applications," Canadian Geotechnical Journal, vol. 49, no. 7, pp. 796–811, 2012. [3] J. T. K. Bennert, A. Maher, and N. Gucunski, "The use of recycled concrete aggregate in roadway pavement applications," Transportation Research Record, no. 1714, pp. 33–41, 2000. [4] A. Arulrajah, J. Piratheepan, T. Aatheesan, and M. Bo, "Geotechnical properties of recycled crushed concrete in pavement applications," Journal of Materials in Civil Engineering, vol. 25, no. 8, pp. 1077–1088, 2013. [5] J. Molenaar and A. A. van Niekerk, "Effects of gradation, composition and degree of compaction on the mechanical characteristics of recycled unbound materials," Transportation Research Record, no. 1787, pp. 73–82, 2002. [6] A. Katz, "Properties of concrete made with recycled aggregate from partially hydrated old concrete," Cement and Concrete Research, vol. 33, no. 5, pp. 703–711, 2003. [7] P. Kumar and D. Gupta, "Utilization of construction and demolition waste in pavement construction: A review," International Journal of Pavement Research and Technology, vol. 12, no. 4, pp. 375–385, 2019. [8] A. Horpibulsuk, C. Suksiripattanapong, A. Arulrajah, and S. Shen, "Strength development in cement stabilized silty clay using calcium carbide residue and fly ash," Construction and Building Materials, vol. 65, pp. 301–309, 2014. [9] B. V. V. Reddy and K. S. Jagadish, "Utilization of industrial wastes in construction materials," Building and Environment, vol. 38, no. 10, pp. 1281–1288, 2003. [10] R. Muntohar and G. Hantoro, "Influence of rice husk ash and lime on engineering properties of clayey subgrade," Electronic Journal of Geotechnical Engineering, vol. 5, pp. 1–9, 2000.