Comparative Life Cycle Assessment (LCA) of Different Asphalt Emulsion Types
Loading...
Authors
Ostovar, Amirhossein
Issue Date
2023
Type
Thesis
Language
Keywords
Asphalt binder , Asphalt Emulsion , Cradle to gate , GaBi , Global Warming Potential (GWP) , Life Cycle Assessment (LCA)
Alternative Title
Abstract
The construction and maintenance of road infrastructure plays a vital role in modern society, with asphalt being a predominant material used for pavement construction. Asphalt emulsions are commonly used in several pavement applications. They are effective for preventive and corrective maintenance on asphalt or concrete pavements, base stabilization, new and rehabilitated pavement construction, and the recycling of end-of-life pavements. As environmental concerns increase and sustainability gains prominence, it becomes essential to evaluate the environmental impacts of various road construction materials and techniques. The principles of sustainability strive to integrate essential environmental, social, and economic elements into the process of decision-making. Life Cycle Assessment (LCA) is a methodology that quantifies the environmental impacts throughout the complete life cycle of a product or system, encompassing impacts that manifest at various stages within the supply chain. The primary objective of this research is to develop comprehensive framework, models, and databases for various types of asphalt emulsions at the production facilities. This effort is designed to quantify the environmental impacts of different asphalt emulsions, facilitating data-driven and integrated decision-making processes. The study's system boundary extends from cradle to gate, with the declared unit being 1 metric ton of asphalt emulsion. The study relies on up-to-date and illustrative data, including raw materials, asphalt emulsion formulations, energy sources, plant properties, and transportation information. Notably, the study specifically targets cationic asphalt emulsions. The following most utilized asphalt emulsions were selected after reviewing the specifications for all 50 State Departments of Transportation (DOTs): CSS 1, CSS-1H, CRS-2, and CRS-2P. Data collection was sourced from the comprehensive investigation of 17 asphalt emulsion production facilities across the United States (US).This study was organized in three phases: 1. Developing a life cycle inventory (LCI) database for asphalt emulsions. 2. Developing an appropriate LCA model for asphalt emulsion production. 3. Conducting a thorough life cycle impact assessment (LCIA) for various asphalt emulsion types, followed by a comparative analysis. Through these phases, an up-to-date LCI database was developed for asphalt emulsions to quantify their environmental impacts and for proper LCA modeling. Data collection involved literature reviews, asphalt emulsion supplier’s data, and the updated 2023 GaBi database. The LCIA analysis was conducted using GaBi software (version 10.7.1). Finally, a comparative analysis was conducted for the four evaluated asphalt emulsions, and a sensitivity analysis was performed to identify influential factors affecting their environmental impact. The results indicated that, overall, rapid-setting cationic emulsions (CRS-2 and CRS-2P) are more environmentally friendly. Additionally, the environmental impacts of CSS-1 and CSS-1H were found to be relatively close. Asphalt emulsions are respectively ranked from the lowest to the highest environmental impacts as CRS-2, CRS-2P, CSS-1H, and CSS-1H. The sensitivity analysis revealed that the hotspots for environmental impacts in asphalt emulsion production are, ranked from highest to lowest: the quantities of emulsifier, latex, and asphalt binder. In other words, the emulsifier exhibits the highest percentage change in global warming potential (GWP) per kilogram among the components of asphalt emulsion, followed by latex and asphalt binder.
Description
Citation
Publisher
License
Creative Commons Attribution 4.0 United States