Large quantities of greenhouse gases (GHG) are emitted in producing and acquiring materials for the construction, maintenance, and rehabilitation of highway infrastructure. The objective of this paper is to develop and illustrate a method that can be applied by state agencies to quantify the life-cycle emissions associated with different pavement designs. It applies existing life-cycle assessment (LCA) methods that integrate process-level construction data. The research emphasizes the construction phase and contributes a method that can be used to develop and analyze construction phase life-cycle inventories. It describes on-site collection of material and equipment usage data during construction and rehabilitation operations. Departing from traditional approaches that tend to use LCA as a way to compare alternative pavement materials or designs on the basis of estimated inventories, this paper proposes a shift to a context-sensitive process-based approach that uses actual observed construction data to ca...

Purpose – This paper aims to provide an integrated framework of life cycle assessment (LCA) and life cycle cost analysis (LCCA) for assessing alternative technologies, processes, and/or activities, with focus on concrete pavements. Design/methodology/approach – LCA and LCCA are used to evaluate environmental and economic impacts of substituting different percentages of fly ash and slag into continuously reinforced concrete pavement (CRCP) and jointed plane concrete pavement (JPCP). Impacts are determined over different life cycle phases. Findings – An LCA of the extraction phase indicated that JPCP pavement had 33-62 percent less emissions than CRCP pavements, when only steel consumption was considered. When cement was considered, JPCP pavement had almost 40 percent greater emissions then CRCP for all mix types. An LCCA showed that over the entire life cycle phases studied, CRCP pavements had about 46 percent more costs than JPCP. However, when only maintenance costs were considered, CRCP pavement cost 80 percent less to maintain than JPCP over the studied period of 35 years. Originality/value – The study is a step towards using an integrated framework to evaluate the performance of different materials and technology. The same framework could be conducted for different kinds of asphalt pavements and concrete pavements, as well as other infrastructure that makes up the built environment, with the goal of making decisions that take into account design considerations, environmental impacts, and cost effectiveness.

The recent enactment of the Buy Clean Act (2017) in California requires highway construction contractors to produce an environmental product declaration (EPD) at the point of installation for a list of all eligible construction materials. An EPD is an instrument that communicates life cycle assessment (LCA) outcomes for a product or process in compliance with the ISO Standard 14025. LCA methodology requires the use of life cycle data from interconnected industries and sectors that contribute to the supply chain of a product. This provides a challenge of consistent and reliable use of inventory data for the LCA of pavements, specifically when considering the geographic expanse of energy profiles, supply chain diversity of pavement materials, and additives. Hence, the objective of this paper is to develop life-cycle information models (LCIMs) that serve two purposes: first, allows for pavement LCA domain-specific knowledge representation, management, and sharing; and second, allows for consistent, reliable, and transparent use of life cycle inventory data. The first purpose is achieved by developing an ontological representation of key components and relationships underlying a pavement LCA to support formal parametric data structures. The second purpose is achieved by identifying life cycle inventories to be mapped to the data structures through a collaboration with the Federal LCA Commons. As LCA software tools are developed to support decision making for departments of transportation, the ontological representation of the pavement domain can serve as a specification outlining a common set of protocols and LCIM designed for reuse to support reliable decision support applications.

Temperature segregation in Hot Mixed Asphalt (HMA) pavement construction leads to performance problems, such as reduced fatigue life. During construction, Quality Assurance (QA) inspection procedures are required to evaluate the pavement condition and detect the segregated areas. In traditional HMA highway construction inspection processes, temperature differences are investigated manually, by sampling the HMA behind the paver. In these processes, inspectors are required to work adjacent to traffic and alongside moving or backing equipment. These processes do not provide a complete temperature profile of the mat, endanger the inspectors’ safety, and require on-site experienced inspectors. An Uncrewed Aerial System (UAS) enables HMA pavement construction inspection to be conducted within a remote, non-destructive, safe, and efficient framework. The objective of this research is to design an automated UAS imaging workflow for HMA pavement construction inspection, mainly locating temperature segregation. The primary contribution of this paper is to provide Departments of Transportations (DOTs) and contractors with workflows for creating enhanced remote inspection procedures and detailed thermal profiles of the placed HMA mat. The application of the proposed workflow is illustrated using an HMA construction project in Michigan.

Construction activities are exposed to unpredictable external events and internal dynamic feedbacks of constraints which deviate projects from as-planned duration and costs. In practice, various decisions have been used to minimize the impacts of risks. Learning from experiences is valuable which requires historical data collection and analysis. To avoid the high cost in direct data collection and difficulties in studying single decision impacts, we present an alternative to study and optimize decision strategies. Interactive Construction Decision Making Aid (ICDMA) is an interactive simulator which allows users to implement different decision strategies on the defined projects. All the project information and decision data in the simulation are recorded electronically. We started with five candidate strategies and analyzed data for general patterns. New hybrid strategies were generated based on the data analysis. Reimplementation of new strategies showed improvement in cost and duration management, validating the feasibility of strategy optimization through interactive simulation.

The objective of this study is to assess the sensitivity of concrete’s embodied global warming potential (GWP) to life-cycle assessment (LCA) parameters. Specifically, the study investigates the concrete mixture development stages of an LCA dealing with materials extraction, transportation to the production facility, and mixing at the production facility. These same stages are used to estimate a concrete mixture’s environmental impacts within environmental product declarations (EPDs). This study explores the framework of a spring-and-dashpot model to represent the carbon emissions from concrete production. The spring-and-dashpot model is introduced and verified in this work. The model identifies the two parameters within an LCA that most affect the GWP of a concrete mixture. Using this framework, the study investigates the sensitivity of a concrete mixture’s carbon emissions to those two most influential parameters. This model was used to assess the uncertainty of model-, laboratory-, and field-based concrete mixture designs. The mechanical performance and durability of concrete mixtures from laboratory and field data sets were compared with their calculated concrete GWPs and displayed no correlation, even accounting for GWP’s uncertainty, suggesting that a strong and durable concrete can also be sustainable.