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.

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.

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.

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.

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.

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.