This current investigation was conducted to improve performance of traditional pavement by reusing/utilizing industrial waste materials in bituminous concrete mixtures for flexible pavements, thereby promoting waste management practices. The optimum mix was found to be at 3% L.D.P.E. with 4% W.E.O., &5% crumb rubber, and having bitumen percentage content of 4.5%. A higher content of waste incorporationwas found to enhance brittleness and deformation. This study assessed the optimalmixes or optimal mix ratios for their dissemination, brittleness, ductility, and specific gravity characteristics. Best/optimal results were identifiedwhile using ratios of 3% L.D.P.E., 4% W.E.O., &5.0% C.R. with 4.5% bitumen. This ratio was found to result leading to a max. stability of 730.5 kg & 17.25 of flow rate. Thesefindingssuggest that industrial waste can be successfully blended with bituminous construction mixes thereby improving pavement performance and supporting waste management at parallel. Thus reusing industrial waste materials in bituminous construction mixes in optimal ratios can lead to better pavement performance in comparison to traditional pavement but for that the exact ratios must first be calculated for obtaining desired characteristics.

This study explored the use of Rice Husk Ash (RHA) and lime as soil stabilizers for subgrade soil. RHA, a by-product of rice milling, poses environmental hazards if improperly disposed of. The optimal RHA content for subgrade stabilization is 15%, combined with 3% lime. The research found that RHA not only improves subgrade properties but also mitigates environmental pollution and offers a cost-effective stabilization method. The study evaluated engineering properties like plasticity index, maximum dry density (MDD), optimum moisture content (OMC), and California Bearing Ratio (CBR). Results showed a significant decrease in plasticity index and an increase in MDD with RHA addition up to 15%. However, further increase in RHA content led to a decrease in MDD. The combination of 15% RHA and 3% lime exhibited the highest CBR improvement (61.48%), indicating enhanced soil strength. This research suggests that RHA may be a sustainable and cost-effective subgrade stabilization material that improves pavement performance and waste utilization. RHA is abundant, easy to obtain, and economical as compared to cement as a soil stabilizer, reducing disposal issues and environmental impact.

While recycling technologies offer solution to the challenges associated with end-of-life tires (ELT), the reliance of the industry on nonrenewable sources raises concerns. The objective of this cradle-to-gate lifecycle assessment study was to quantify the potential environmental impacts due to recycling of ELT into multiple outputs: crumb rubber (CR), micronized rubber powder (MRP), and reclaimed rubber (RR). Thirty-six scenarios were analyzed including three products and two ELT sources using six electricity mix scenarios transitioning the nonrenewable to renewable sources. The global warming potential due to the production of CR, MRP, and RR from domestic ELT were 1.13 × 10⁴, 3 × 10⁴, and 3.63 × 10⁴ kg CO₂ eq., respectively, while 50 % transition to renewables reduced them by 10–15 %. Further, MRP showed the highest land occupation and water consumption potential. Overall, this research provided a holistic overview of current and future impacts of tire recycling industry supporting sustainable practices.

The objective of this research was to evaluate the lifecycle costs associated with emerging pavement maintenance technologies, namely, in-situ rejuvenation and very open emulsion asphalt concrete (ZOEAB+), and scrutinise their suitability over corrective resurfacing maintenance using a stochastic approach. A rational lifecycle inventory was developed by conducting interviews and questionnaire surveys with experts and referring to standard guidelines and international databases. The net present value (NPV) was found sensitive to 12 different inputs with traffic growth rate and discount rate causing the highest uncertainty followed by gasoline and diesel prices. Monte Carlo simulations suggested that the median uncertainty in NPV by using in-situ rejuvenation and ZOEAB+ was 13% and 4% lower than resurfacing. It is envisioned that the research outcomes will assist decision-makers in understanding the uncertainties and costs associated with different maintenance alternatives in the early stages of the project to foster procurement of sustainable and circular pavement maintenance strategies.

To achieve climate neutrality, synergies between circular economy (CE) and carbon reduction need to be established in the context of transport infrastructure. Implementation of the circular economy and resource efficiency (RE) policies have the potential to facilitate decarbonization targets, while using fewer natural resources, maintaining or enhancing biodiversity and providing regenerative design for generations to come. This paper presents the interpretation of RE and CE within transport infrastructure in the context of the CERCOM and LIAISON projects. As part of CERCOM, a strategic review of current practice was carried out to develop a definition of CE within transport infrastructure, and provide the successes and barriers for further transition from a linear to a circular economy. A Risk Based Assessment Framework (RBAF) and associated software tool were developed to provide a means to evaluate the impacts of certain measures and prioritize areas that require further research or investigation. LIAISON will provide further progression in this regard, and develop a methodology, support tools and close to market technological solutions to transform EU Transport Infrastructure into a more sustainable and low carbon economic activity.

This paper introduces the new RILEM Technical Committee on Alternative Paving Materials – Design and Performance (TC APD), which builds upon the foundational efforts of the former TC 279-WMR focused on the Valorisation of Waste and Secondary Materials for Roads. The TC APD aims to advance the understanding of alternative paving materials, emphasizing their design and performance as essential components of road composites. The committee addresses three areas of investigation, each dedicated to examining the current technological state of the art, the design process and the field performance of composites incorporating alternative paving materials. The manuscript provides a comprehensive overview of the TC's background, outlines the research objectives and activities proposed, and discusses the committee's position within RILEM and the broader research community. Additionally, it details the anticipated outcomes and the potential impact of the committee's work on advancing the field of sustainable road construction.

Refurbishing of milled asphalt into new bound layers of pavement is recognized as a sustainable maintenance practice. However, limited attention has been paid towards investigating their circularity aspects. Furthermore, evolving legislative requirements call for integration of circularity and sustainability facets. Therefore, this study presents a flexible framework that aims at assessing and integrating the environmental, economic, and circularity aspects associated with two maintenance alternatives, i.e., reconstruction of pavement with a bound base layer using bituminous materials (BSM) versus routine patch repair and resurfacing. The integration of different assessment categories was performed using a metric termed as net risk reduction gain (NRRG). The results revealed that the NRRG for BSM option was 2.5 times higher than routine maintenance over a 50 year analysis period, thereby emphasizing its higher circularity and sustainability benefits. The proposed framework is envisioned to pave way for integration of circular thinking along with sustainability considerations for pavement design and construction.

This chapter presents the effects of using crumb rubber (CR) and aircraft composite wastes (CW) on pervious concrete (PC) characteristics and outlines the systematic framework for lifecycle assessment (LCA) of PC pavement (PCP) systems. The incorporation of fine CR (1.18–0.15 mm) in PC resulted in improved mechanical properties, while maintaining the desired functional attributes. Though the addition of CW in PC did not alter the PC properties significantly, it allowed for the disposal of 1.47–3.90 t of CW in one-lane km PCP. LCA indicated no major differences between the environmental impacts of control and CW-modified PC. Furthermore, the environmental burdens of PCP were lower than the cement concrete pavements by about 3%. This chapter is intended to serve as an important repository that paves the way for research and implementation of the PCP products engineered with recycled waste materials, thereby serving as a low-impact development strategy for green urban infrastructure.

Pervious concrete pavements (PCP) have been successfully constructed in low-to-medium volume roads attributed to their sustainability benefits. Several studies have investigated the hydrological performance of PCPs, but limited attention has been given to the structural and environmental aspects. Thus, the objective of this study was to monitor the structural, hydrological and environmental performance of two PCP parking lots built using in-situ and ready-mix methods. Structural distresses were classified based on the distress identification manual, while the infiltration tests were performed every three months for three years to quantify the clogging rate. Joints/edges formed the weakest zones, while inefficient maintenance caused 98% clogging within 18 months. Further, in-situ mixing was 17% cheaper and 0.74% carbon-intensive than ready-mix technology. Overall, this research is envisioned to pave way for the development of guidelines that classify distresses and severity levels specific to PCPs, which also cover adequate maintenance recommendations for field implementation.

The use of nondestructive ultrasonic pulse velocity (UPV) testing to assess the hardened properties of pervious concrete (PC) mixtures is an emerging research area. Further, UPV has been successfully used to determine the effective flow resistivity (EFR) of asphalt concrete and cement concrete pavements. However, no research studies have focused on understanding PC characteristics using EFR. Thus, the major objectives of this study were to assess the suitability of UPV testing for characterizing PC mixtures and to quantify their EFR, which is a measure of the material’s characteristic impedance and is dependent on the mix variables along with porosity. Thirty-six control and sand-modified PC mixtures were prepared with four aggregate gradations, and three levels each of water-to-cement (w/c) and aggregate-to-cement (a/c) ratios. Test results indicated that EFR was significantly dependent on the mix variables, with aggregate gradation being the most influential factor (six and eight times higher than w/c and a/c ratios, respectively). Lower EFR or higher sound absorption capacity was reported for PC with higher porosities. The sand-modified PC mixtures had higher EFR (by 4%–12%) than the control PC, and consequently lower sound absorption capacity, attributed to the presence of mortar that densified the mixes. Further, good-to-excellent correlations were obtained for various PC properties with UPV and EFR, which underscored the potential of UPV in characterizing PC. The major contribution of this research was the development of a simple, fast, and cost-effective approach, which can be suitably adopted as a quality-control test to determine PC mixture properties.

Although multiple studies have reviewed the mechanical, durability, and acoustic characteristics of rubberized concrete (RC) mixtures, very limited studies have focused on a comprehensive collation of literature pertaining to their environmental, economic, and field implementation aspects. Therefore, this paper presented the state-of-the-art pertinent to environmental and economic aspects, thermal savings in terms of energy and emissions, and field applications of RC mixtures. Further, none of the studies have systematically reviewed the literature specific to specialty RC mixtures (pervious concrete, self-compacting concrete, and roller-compacted concrete), which was thoroughly examined. The various rubber treatment methodologies to enhance rubber-cement interaction were underscored and the impact of rubber aggregates on mix properties was discussed. Importantly, this state-of-the-art review identified the scope for future advancements at environmental, economic, and technical levels, which is envisioned to advance the widespread implementation of RC and pave the way for creation of an eco-efficient built environment.

Implementation of the circular economy and resource efficiency has the potential to significantly tackle the root causes of global challenges such as climate change, biodiversity loss and pollution whilst at the same time providing regenerative design for generations to come. The CEDR funded CERCOM project facilitates a move towards circular public procurement of national road infrastructure. A flexible and stable approach using ranked interpolation is used to generate KPI values for various criterion, where the user can specify the desired level of complexity based on scheme requirements and data available. The framework considers technical, economic, environmental and social criteria, as well as circularity, while assessing the change in risks in moving from a linear to a circular economy. National Road Authorities (NRAs) are at different maturity levels in relation to circularity. The developed framework caters for this, allowing flexibility for NRAs to tailor their application of the framework to suit their maturity level and the scheme under consideration. The outcome is a user-friendly intuitive tool with a step-by-step approach to enable informed decision making around adoption of the principles of circular economy in the maintenance of highway infrastructure.