The global rise in vehicle ownership has led to a significant accumulation of waste tires, with many ending up in landfills or incinerated, resulting in considerable environmental impacts. Several end-of-life solutions have been developed to repurpose these tires, and one promising approach is converting them into crumb rubber for use in road infrastructure. Crumb rubber has been incorporated as a stabilizing agent in asphalt mixtures, Portland cement concrete, base and sub-base granular layers, and subgrades. This application not only mitigates environmental harm but also often enhances the mechanical performance of these materials. Additionally, crumb rubber (CR) serves as a low-carbon material, offering environmental benefits such as reduced carbon footprint. This study provides a comprehensive literature review on the use of crumb rubber in road infrastructure materials, examining aspects such as treatment methods, mix design, mechanical properties, durability, and environmental impacts. It also highlights knowledge gaps and potential research directions to advance the application of crumb rubber in the road infrastructure industry. The findings suggest that, at appropriate dosages (in asphalt mixtures, for example, it is between 15–20% by weight of asphalt binder), crumb rubber can shift from being an environmental burden to a valuable resource across numerous road infrastructure applications. This review aims to guide agencies, designers, engineers, and other stakeholders in informed decision-making.

Pavement structures are one of the most critical civil infrastructures for the socio-economic development of communities. However, pavement construction demands an elevated financial budget and generates large amounts of environmental impacts. Accordingly, the new trends in daily engineering practices have integrated sustainability criteria verification into traditional pavement design procedures. Thus, this research explores the sustainability implications of asphalt pavement incorporating a Cement-Treated Base (CTB) and Recycled Concrete Aggregate (RCA) within the local context of a Global South country. The environmental and economic performances of four different types of asphalt structures were assessed, each differing in how the CTB is employed. These structures include conventional flexible pavement, semi-rigid pavement, inverted base pavement, and simple composite pavement. Furthermore, each structure is evaluated under four varying contents of coarse RCA (i.e., 0%, 15%, 30%, and 45%) in their asphalt mixtures. This approach results in a comprehensive analysis spanning 16 unique scenarios, providing valuable insights into the interplay between RCA content and CTB inclusion for sustainable infrastructure development. It is important to highlight that the Life-Cycle Assessment and Life-Cycle Cost Analysis methodologies were implemented to perform the environmental and economic inspections, respectively. Overall, this investigation demonstrates that although pavement structures comply with mechanistic design standards, they can yield significantly different cost effectiveness and environmental burdens from each other. Therefore, executing a sustainability-related appraisal is essential for accomplishing definitive infrastructure designs. Consequently, this research effort is expected to be used by stakeholders (e.g., civil engineers, designers, and governmental agencies) to support data-driven decision making in the road infrastructure industry.

In this article we study the infiltration rate and flow characteristics of water through concrete-geocell liners by experimental and analytical means. Geocells filled with concrete have been used in the construction of many hydraulic works, such as shore protections (both marine and riverine), spillways, and canal liners; these liners have been reported to offer high performance, as they are able to withstand large flow velocities, hydrodynamic effects, and environmental stresses, while still being more cost-effective than other hard-armor systems such as reinforced concrete and articulating concrete blocks (ACBs). Despite their increasing use there is no report of their hydraulic conductivity in the literature, which this paper aims to fulfil. First, an analytical solution to the problem is achieved by parting from the incompressible Navier-Stokes equations and applying reasonable assumptions to arrive at a formula that relates flow rate to pressure gradient, fluid properties, and importantly, the hydraulic aperture (the idealized gap at the concrete-geocell interface); this gap is then estimated using the ACI-209 method for the prediction of concrete shrinkage, resulting in the proposed semi-analytical method. The formulation was then evaluated experimentally by conducting hydraulic tests on full scale geocell specimens filled with concrete under conditions that are deemed representative of real case applications. The results indicate that the proposed methodology has satisfactory predictive capabilities and provides flow rate estimates in accordance with measured data.