Sapkota, Kiran (2023) Development of Sustainable Pavements: An Experimental and Finite Element Analysis Study. Research Master thesis, Victoria University.

Abstract

The potential of using recycled aggregates, such as construction and demolition waste, and glass waste, has been considered in the asphalt industry in recent decades. However, only a low percentage of these materials have been used in the mixtures as permitted by relevant standards and guidelines. With the predicted increase in the population and industrial activities, not only the generation of waste is expected to rise, but also the demand for construction materials in transportation infrastructures is increasing, resulting in the depletion of natural resources. This research investigates the feasibility of increasing the percentage of recycled aggregates to 100% in hot mix asphalt (HMA). Recycled concrete aggregate (RCA), recycled glass (RG), and reclaimed asphalt pavement (RAP) were used to develop an HMA suitable for light to medium traffic roads. First, the properties of recycled aggregates were determined, and potential mix designs were proposed using an innovative approach that considered the industry's needs. Next, the mechanical and volumetric properties of the proposed mixtures were determined together with those of mixtures made of natural aggregates for validation. The resilient modulus response of the mixtures was determined under different temperature conditions. In general, the proposed HMA exhibited advanced mechanical and resilient modulus performances, i.e., a 45 to 145% increase in stiffness and up to 99% increase in Marshall stability when compared to conventional HMA. Experimental results showed that the newly developed mixtures have superior strength, resilient modulus and moisture susceptibility performances compared to conventional mixtures. The experimental outcomes were translated into material properties as design input that were next used for simulating four different flexible pavements using the CIRCLY7.0 software. The four pavement profiles included three flexible pavement systems that had 100% recycled material aggregates in the surface course at different proportions and one pavement profile that had 100% natural aggregate. The designed pavement profiles were also modelled using finite element analysis (FEA) softwares, ABAQUS and Strand7, (SIMULIA, 2011; Strand7, 2010) for further evaluation of the performance and comparison of the stress-strain responses due to vehicle loadings. The findings of this research provide the industry with evidence-based insights into the performance of HMA with increased quantities of recycled materials, thereby promoting green pavement construction materials.

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