With limited funding and a desire to reduce environmental impact, there is a lot of pressure on road Authorities to develop decision making policy to manage better, build and maintain the road network sustainability. One of the solutions is to use various life cycle analyses. Numerous tools are available for different analyses, but they usually evaluate the construction from one perspective (economical, environmental, or social). Therefore, it was decided to develop a tool, which combines economic (Life Cycle Cost Analysis) and environmental (Life Cycle Assessment) analyses. The given study presents the methodology of the self-developed calculation program, which compare full-depth road constructions. Paper also shows shortcomings when calculation does not include all life cycle processes. In this study, five different road pavement constructions and reconstruction plans were compared. The difference between these pavements was in the layer thickness, recycled asphalt content in asphalt layers and the use of cement or fly ash in the road base layers. The results showed that the full depth reclamation technology in comparison to the full-depth removal and replacement reduce emissions by 60% and costs by 50%.
Reclaimed asphalt (RA) and Warm mix asphalt (WMA) are two widely used environmentally friendly mixtures in the paving industry. This study compares the laboratory performance of conventional hot mix asphalt (HMA) with virgin WMA, and WMA containing 60% RA content, using thermal stress restrained specimen test, wheel tracking test, and indirect tensile strength test. Based on test results, a reduction of 15 °C in mixing temperature was achieved for WMA mixtures compared to HMA using the given chemical additive. The virgin WMA mixture showed superior cracking resistance but lower rutting resistance than HMA, and incorporation of RA material without any further modification in the binder, deteriorated both cracking and rutting performance of WMA. It was also shown that laboratory short-term aging can significantly affect the performance of the mixtures.
This study used a cradle-to-cradle Life Cycle Assessment (LCA) approach to evaluate the environmental potentials of urban pavements. For this purpose, the urban road network of the City of Münster (Germany) was selected as the case study, and comprehensive data for several phases were collected. The entire road network is composed of flexible pavements designed according to specific traffic loads and consists of main roads (MRs), main access roads (MARs), and residential roads (RSDTs). Asphalt materials, pavement structures, and maintenance strategies are predefined for each type of road and are referred to as “traditional” herein. Some pavement structures have two possible maintenance strategies, denoted by “A” and “B”, with distinguished periods of intervention. To evaluate the impact of using recycled materials, we considered alternative pavement structures composed of asphalt materials containing a greater amount of reclaimed asphalt pavement (RAP). The study was carried out considering analysis periods of 20, 50, 80, and 100 years and using two indicators: non-renewable cumulative energy demand (nr-CED) and global warming potential (GWP). The results show that the use of higher amounts of RAP can mitigate negative environmental impacts and that certain structures and maintenance strategies potentially enhance the environmental performance of road pavements. This article suggests initiatives that will facilitate the decision-making process of city administrators to achieve more sustainable road pavement constructions and provides an essential dataset inventory to support future environmental assessment studies, particularly for European cities.
26 March 2021 in Road Materials and Pavement Design
Several studies evaluated the feasibility of using residues to compose asphalt mixtures. However, the demand for treatments are often neglected in determining the environmental impacts. This study aims to elucidate the decision-making process over the application of residues (e.g., red mud and fly ash) to produce asphalt mixtures. For comparison purposes, limestone and dolomite are used as reference fillers. The cradle-to-gate approach is applied within three scenarios. In the first scenario, the treatment of the residues is included in the modelling, the second excludes treatment, and the third scenario evaluates the environmental impacts of the residues deposited in landfills. To perform the analysis, indicators such as Global Warming Potential, Acidification, and Cumulative Energy Demand are applied. The results show that the treatment provided to the residues strongly influences the environmental impacts of the production of asphalt mixtures and may be crucial to define the feasibility of the residues application.
17 January 2018 in Road Materials and Pavement Design
This paper present a laboratory study on the influence of filler type on the rheological properties of mastics. Mastic is the main component that undergoes any deformations in asphalt structure. Low shear resistance can lead to susceptibility to permanent deformations. The type of filler used in mastic can highly influence its rheological properties. The main objective of the study was to evaluate different types of mineral fillers and their stiffening effect on unmodified and modified mastics in terms of permanent deformations. During this study performance of three mineral fillers, namely Jelsa granite, Portland cement and Aggersund limestone were investigated. The fillers used in this study were evaluated according to common filler characteristics, such as Rigden voids (RV), density, specific surface area, fineness modulus and others. Dynamic shear rheometer was used for testing mastics under repeated shear stress with multiple stress creep recovery test method. Mastics performance was tested under three different temperature conditions. Analysis of the results showed that limestone filler provide best stiffening effect. The main factors affecting that is its fine gradation, high percentage of RV and high specific surface value. This subsequently results in high amount of bitumen being as fixed one. Granite filler with low value of RV showed poor performance.