Sustainable Pavement Engineering and Road Materials

In a similar way to many other engineering fields, the road pavement industry strongly affects the critical issues of our generation, including climate change, pollutant emission, the exploitation of natural resources and economic crises. For this reason, technicians and researchers are searching ravenously for sustainable solutions to implement in current road construction systems with the following goals: To reduce the consumption of energy and virgin materials; To run environmentally and economically friendly maintenance; To recycle waste from different industrial processes; To decrease the noise, the pollution and the heat generated by traffic, particularly in urban contexts. This Special Issue aims to collect high-quality studies that combine the aforementioned solutions, including works pertaining to: The hot, warm, and cold recycling of reclaimed asphalt pavement; Marginal materials for asphalt pavements; Innovative sustainable materials; Durability and environmental aspects; Structure performance, modeling and design; Advanced trends in rehabilitation and preservation; Surface characteristics and road safety; Management system/life cycle analysis; Urban heat island mitigation; Energy harvesting

Recent Advances and Future Trends in Pavement Engineering

This Special Issue “Recent Advances and Future Trends in Pavement Engineering” was proposed and organized to present recent developments in the field of innovative pavement materials and engineering. The 12 articles and state-of-the-art reviews highlighted in this editorial are related to different aspects of pavement engineering, from recycled asphalt pavements to alkali-activated materials, from hot mix asphalt concrete to porous asphalt concrete, from interface bonding to modal analysis, and from destructive testing to non-destructive pavement monitoring by using fiber optics sensors. This Special Issue partly provides an overview of current innovative pavement engineering ideas that have the potential to be implemented in industry in the future, covering some recent developments

Evaluation of Emissions by Different Analysis Method at Hot Mix Asphalt Plant Combustion Source

The combustion process for the asphalt mixing in hot mix asphalt (HMA) plant can produce harmful flue gases emission into the atmosphere. Combustion activities produce heat for industrial usage when fuel reacts with oxygen in the air under suitable conditions. High concentrations of undesirable emissions can be formed if the combustion is not properly controlled during the reaction. This paper gives an overview on the method and measurement of these emissions in combustion analysis by focusing on the three types of analysis methods which are laboratory testing analysis, on-site emission analysis, and theoretical analysis. Three types of data were prepared in order to achieve the objective of the study, which are literature study, site visit, and laboratory analysis. The result shows that there is slightly different emission results even though they came from the same source. Clearly, the analysis shows that the air-fuel ratio during combustion can have a significant effect on the emission result. The excess air supplied can cause dilution to the emission and leads to a low emission value

LIFE CYCLE INFORMATION MODELS WITH PARAMETER UNCERTAINTY ANALYSIS TO FACILITATE THE USE OF LIFE-CYCLE ASSESSMENT OUTCOMES IN PAVEMENT DESIGN DECISION-MAKING

The objective of this dissertation is to develop Life Cycle Information Models (LCIMs) to promote consistent and credible communication of potential environmental impacts quantified through Life-Cycle Assessment (LCA) methodology. The introduction of Life Cycle Information Models (LCIMs) will shift the focus of pavement LCA stakeholders to collect reliable foreground data and adapt to consistent background data present within LCIMs. LCA methodology requires significant Life Cycle Inventory (LCI) data to model real world systems and quantify potential environmental impacts. The lack of guidance in ISO standards on consistently compiling LCI data and defining protocols for modeling lowers the reliability of LCA outcomes. In addition, LCA outcomes are communicated as point estimates despite the variations associated with input data. These limitations provided two motivations for this dissertation. The first motivation is to develop an information modeling approach to support the formal specification of relationships between pavement LCA flows and processes, while mapping them to a consistent set of background LCI and foreground process parameters. The second motivation is to develop the margins of error within LCA outcomes by propagating different types of uncertainties. An illustration of the discussed methodology is provided for the case of Hot-Mix Asphalt (HMA) mixtures containing varying amounts of Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS). LCIMs serve as a building block for a complete LCA and formalizing the underlying model and upstream datasets. This builds trust among pavement LCA stakeholders by promoting the use of consistent underlying relationships between unit product systems, processes, and flows within pavement LCA system boundary and mapping them to consistent, transparent public background datasets. Pavement LCA stakeholders are empowered to develop context-specific LCA outcomes using LCIMs and can reliably incorporate these outcomes within decision-making by highlighting the margins of error associated with the results. The methodology discussed in this dissertation is timely with emerging legislations such as the Buy Clean Act (2017) in California that requires highway construction contractors to produce LCA based Environmental Product Declarations (EPDs), at the point of installation, for a list of all eligible construction materials

Evaluation of Emissions by Different Analysis Method at Hot Mix Asphalt Plant Combustion Source

The combustion process for the asphalt mixing in hot mix asphalt (HMA) plant can produce harmful flue gases emission into the atmosphere. Combustion activities produce heat for industrial usage when fuel reacts with oxygen in the air under suitable conditions. High concentrations of undesirable emissions can be formed if the combustion is not properly controlled during the reaction. This paper gives an overview on the method and measurement of these emissions in combustion analysis by focusing on the three types of analysis methods which are laboratory testing analysis, on-site emission analysis, and theoretical analysis. Three types of data were prepared in order to achieve the objective of the study, which are literature study, site visit, and laboratory analysis. The result shows that there is slightly different emission results even though they came from the same source. Clearly, the analysis shows that the air-fuel ratio during combustion can have a significant effect on the emission result. The excess air supplied can cause dilution to the emission and leads to a low emission value

High Reclaimed Asphalt Pavement in hot mix asphalt

When old roads have to be replaced, the existing pavement, known as Reclaimed Asphalt Pavement (RAP) is ripped up, milled, and stockpiled and can be used in the creation of new mixes in order to save money and resources. New Jersey state specifications limit the percentage of RAP that can be used to 15% for surface courses and 25% for the intermediate and base courses; however, other states have implemented much higher RAP percentages. The limitations are placed because the interaction between the virgin and residual RAP binder is unknown, with respect to the amount of residual binder that is active in the mix and the effect that this blended binder will have on performance since aged binder has a tendency to be stiffer. In this report, the methods and findings are explained for low temperature laboratory performance of asphalt mixes with 25% and 35% RAP as well as a control mix and RAP samples from Delaware. In addition to this, a coating study, blending study, variability study, and cost analysis were performed and the use of blending charts was investigated. The Superpave Mix Design Excel Spreadsheet was also modified to account for degree of blending. The final section of the report provides recommendations for the use of RAP in New Jersey

Development of a Wireless Real-Time Productivity Measurement System for Rapid Construction Operations

Existing on-site construction productivity measurement methods have some common limitations, such as the inability to provide data to engineers and project managers for real-time analyses and the difficulties of sharing data among participants involved in construction operations. To address these shortfalls, a wireless real-time productivity measurement (WRITE) system was developed. To validate the system, field experiments were conducted at highway and bridge construction sites. Statistical methods, such as the hypothesis test, the normality test, the paired t-test, and the Wilcoxon Signed Rank Test, were conducted to systematically analyze the experimental data. Results of the statistical analyses proved that the developed system generated identical productivity measurements compared to the stopwatch method, which is considered the classic productivity measurement method. In addition, a procedure to improve the on-site construction using the WRITE System and benchmarking technique was developed. The WRITE System has a potential to strengthen communication and coordination among participants involved in the infrastructure construction process by providing more accurate productivity information in real time

Mechanical Performance Of Warm Mix Asphalt-Treated Bases Incorporating Recycled Asphalt Pavement

DissertationThe depletion of natural resources, the elevated cost related to the construction and the rehabilitation of pavements, the progressive change of the climate, the high heat and harmful gas emission into the atmosphere are the concerns engineers, academics, scientists and politicians have been addressing. They are co-operating toward finding efficient solutions to mitigate these global issues. Thus, the advent of Warm Mix Asphalt (WMA) incorporating Recycled Asphalt Pavement (RAP) as a long-term solution to partially or totally participating in remediating the problem of global warming, climate change and the preservation of environmental resources has gained prominent interest in certain European countries and Asia, North America and most recently in South Africa. This thesis, therefore, aims to investigate the performances of the control Hot Mix Asphalt (HMA) technology and the WMA incorporating RAP at 15% and 30% through laboratory experiment and numerical modelling. Consequently, the laboratory studies that involve the mix designs, the production and the testing of asphalt specimens were achieved following both the South African and the international standards. The RAP used at 15% and 30% in the WMA contains 0.8 % of 50/70 grade bitumen. The virgin aggregate called dolerite and the fillers used in the asphalt mixture were obtained at the Lafarge Olivehill Crushers site in Bloemfontein. The Sasobit, as well as the 50/70 grade bitumen binder, were collected in Sasolburg. The numerical simulation of the WMA – 15%RAP, the WMA – 30%RAP and the control HMA was achieved through the Finite Element Method (FEM) in the Abaqus computer program and the Layered Elastic Analysis (LEA) in mePADS. The Linear Elastic Analysis (LEA) was adopted not only to validate the results found in FEM but most of all, to justify the preference of FEM over the LEA. The numerical simulation WMA – 15%RAP pavement structures, the WMA – 30%RAP pavement structures and the control HMA pavement structures was to analyse their mechanical responses under repeated loading. The results of the laboratory experiment show that: the control HMA exhibits lower rutting performance than the WMA –15%RAP and WMA – 30%RAP; the control HMA exhibits lower fatigue cracking performance than the WMA –15%RAP and WMA – 30%RAP; the control HMA exhibits lower ITS (stiffness) performance when compared tothe WMA – 15%RAP the WMA – 30%RAP; the control HMA exhibits close Marshall Stability and Flow performance tothe WMA – 15%RAP the WMA – 30%RAP. As far as numerical modelling is concerned, the results show that the control HMA pavement structures exhibit lower rutting and fatigue cracking performance when compared to the WMA – 15%RAP pavement structures the WMA – 30%RAP pavement structures. Overall, the WMA can successfully incorporate RAP at up to 30% and can be utilized for the new construction and the rehabilitation of low to medium-traffic volume roads