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Background

The widespread use of petroleum-based asphalt binders in the construction industry is accompanied by high material costs due to the volatility of the petroleum market and negative environmental impacts. Petroleum exploration and drilling has been shown to disrupt natural animal habitats and pollute natural water, land, and air resources. Further, hot mix asphalt (HMA) construction requires high working temperatures (135-165ºC), which necessitates large amounts of energy. Production of materials and construction methods used in HMA pavement applications emit greenhouse gases and toxic volatile organic compounds that present health risks to exposed construction workers. The construction industry is in need of greener novel materials and technologies to replace petroleum-based asphalt binders. In order to fulfill this environmental and economic need, direct alternatives for petroleum-based binders need to be investigated.

Research Objective

This research aims to contribute to the advancement of direct alternative materials for petroleum-based asphalt binders. Highly concentrated mixtures of agar hydrogels (i.e., 10% agar) possess similar viscoelastic and temperature-dependence properties when compared to conventional petroleum-based binders (e.g., bitumen, tar) which may make agar well-suited as an alternative binder for pavement applications.

To achieve this goal, the following sub-objectives have been identified:

• Evaluate agar-based binder properties using conventional asphalt binder laboratory testing standards (namely Superpave).
• Evaluate and optimize the stability and durability of agar-based binder asphalt mixes (i.e., agar-based binder and aggregate).
• Quantify system-scale life cycle environmental and economic benefits of agar-based binder use in order to establish quantitative comparisons between novel and traditional binders.

Expected Contributions​

Results from this work have the potential to elucidate a solution for effective design and management of “greener” flexible pavement infrastructure. The novel materials proposed in this research could be implemented in the design and construction of new flexible pavements that are more environmentally conscious. This research and the future implementation of this work could lessen the dependence of road construction processes on crude oil, ultimately lessening the environmental and economic burden of crude oil extraction and processing.

Funding

US Department of Education Graduate Assistance in Areas of National Need (GAANN) Fellowship
Colorado Department of Transportation (CDOT)