Comparative Analysis of Sustainable Pavement Materials in Urban Roadways

Thesis Abstract

Urban road infrastructure demands sustainable and environmentally responsible pavement materials to address the increasing challenges of urbanization, traffic congestion, and climate change. Despite the proliferation of conventional asphalt and concrete pavements, there is a growing need to evaluate alternative, sustainable materials that can enhance durability, reduce environmental impacts, and lower life-cycle costs. This study aims to conduct a comprehensive comparative analysis of sustainable pavement materials used in urban roadways, focusing on their mechanical performance, environmental benefits, and economic feasibility. The specific objectives are to assess the functional performance of selected sustainable materials, such as recycled asphalt pavement (RAP), geopolymer concrete, and permeable pavements; evaluate their environmental impacts through life-cycle assessment (LCA); analyze cost implications over their service life; and develop a decision-making framework for material selection in urban road construction. The research adopts a mixed-methods approach, integrating quantitative laboratory testing, field performance evaluation, and qualitative stakeholder interviews. The population comprises recently constructed urban pavements incorporating sustainable materials within metropolitan regions of the country, with a sample size of 30 pavement sections across three cities. Data collection instruments include standardized mechanical testing equipment for assessing strength and durability (such as compressive and tensile tests), environmental impact assessment tools for conducting LCAs, and structured questionnaires and interview guides for stakeholder perceptions and cost analysis. Validity and reliability are ensured through calibration of laboratory instruments, pilot testing of survey instruments, and triangulation of data sources. Data analysis employs descriptive statistics, analysis of variance (ANOVA) for comparative performance evaluation, and multiple regression analysis to identify key drivers of pavement performance. Additionally, the study applies the Theory of Planned Behavior to examine stakeholder acceptance and the Sustainable Livability Model to understand environmental and social implications. Expected findings suggest that certain sustainable pavement materials, notably geopolymer concrete and permeable pavements, demonstrate comparable or superior mechanical strength, enhanced environmental performance, and cost efficiencies over traditional alternatives. The study anticipates revealing statistically significant differences (p < 0.05) among materials across various performance metrics, with sustainable options possibly yielding lower greenhouse gas emissions, reduced heat island effects, and favorable life-cycle costs. These outcomes aim to fill existing research gaps concerning holistic, cross-sectional evaluations of sustainable materials within the specific context of urban roadways, offering empirical evidence for policy and practice. The contribution to knowledge lies in establishing a validated framework for evaluating and selecting sustainable pavement materials based on performance, environmental impact, and economic factors, thus informing decision-makers, researchers, and practitioners in civil engineering. The main conclusion underscores that sustainable pavement materials, when carefully selected and properly implemented, can significantly improve urban road infrastructure resilience while fostering environmental stewardship. Recommendations emphasize the integration of sustainability criteria into pavement design standards, promotion of stakeholder awareness, and further research to explore long-term performance under diverse climatic conditions. The study advocates for policy enhancements that incentivize the adoption of sustainable materials in urban roadway projects, ultimately supporting sustainable urban development and resilient infrastructure systems.