Analysis of Greenhouse Gas Emissions and the Environmental Impact of the Production of Asphalt Mixes Modified with Recycled Materials

Abstract

This research focuses on the production and construction stages of the life cycle analysis (LCA) of asphalt mixtures modified with industrial waste and by-products, based on the quantification of methane (CH4), carbon monoxide (CO) and carbon dioxide (CO2) emissions produced during these processes. A laboratory-designed and calibrated gas measurement system with a microcontroller and MQ sensors is used to compare the emissions (GHG) of a “conventional” asphalt mix with those emitted by waste-modified asphalt mixes (polyethylene terephthalate and nylon fibres) and industrial by-products (copper slag and cellulose ash). The results obtained show that the gases emitted by each type of material can influence the design criteria from an environmental perspective. Methane gas emissions for asphalt mixes made with polymeric materials increase compared to the production phase of a conventional mix (M1) by 21% for PET and 14% for nylon. In contrast, for mixtures made with copper slag and cellulose ash, this emission is reduced by 12%. In addition, the use of copper slag and cellulose ash to replace natural aggregates reduces greenhouse gas emissions by 15% during the production phase and contributes to the creation of photochemical ozone for a shorter period of time. Regarding carbon dioxide emission, it increases considerably for all asphalt mixes, by 26% and 44.5% for cellulose ash and copper slag, respectively. For asphalt mixtures made of polymeric materials, the increase in carbon dioxide emission is significant, 130% for PET and 53% for nylon. In addition, it is noted that for this type of material, not only the emission of the gas must be taken into consideration, but also the time that the volatile particles spend in the atmosphere, affecting climate change and photochemical ozone (smog). The carbon monoxide gases emitted in the production phase of all the asphalt mixes analysed is similar among them.

Mechanical performance of sustainable asphalt mixtures manufactured with copper slag and high percentages of reclaimed asphalt pavement

“…The progressive social awareness of the need for sustainable industrial development that launched in recent years worldwide has resulted in increasingly demanding environmental agreements and public policies on production [1]. Minimizing the exploitation of natural resources and the emission of pollutants in the manufacturing processes [2][3][4], extending pavement life [5,6] and the management of generated waste have been topics of interest concerning the development of road infrastructure [7].…”

Evaluation of the Mechanical Performance of Warm Bio-Recycled Asphalt Mixtures

“…As a result of high consumption worldwide, the scarcity of this raw material is an important concern in this industry nowadays. In addition, the heating of bitumen at high temperatures for HMA production results in high greenhouse gas emissions [8]. For these reasons, many researchers have focused their work on studying alternative sources and technologies for binders in asphalt mixtures, such as using biobinders and bio-oils derived from different biomass resources, such as cooking oil residues [9], soy oil [10], wood residues [11], or the usage of swine manure [12,13], for paving applications.…”

Environmental Impact Comparison Analysis between a Traditional Hot Mixed Asphalt (HMA) and with the Addition of Recycled Post-Consumer Polyethylene Terephthalate (RPET) through the Life Cycle Assessment (LCA) Methodology

“…Due to its extensive dimensions and high resource consumption, roadway pavements have attracted great attention from researchers focusing on developing sustainable pavements with alternative materials, such as plastic waste as aggregate replacement in asphalt mixtures, that could serve as an environmentally friendly method to dispose of such waste while simultaneously producing high-quality pavements. [1][2][3][4]. With that perspective, studies were developed on the assessment of environmental impact of plastics and polymer recycling from virgin use to post-consumer recyclate, as fiber or composites in the paving industry, applying the life-cycle assessment (LCA) methodology [5][6][7].…”