Volatile organic compounds (VOCs) inhibition and energy consumption reduction mechanisms of using isocyanate additive in bitumen chemical modification

Tianshuai Li, Guoyang Lu, Jiao Lin, Dong Liang, Bin Hong, Sang Luo, Dawei Wang, Markus Oeser

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Tens of millions of tons of polymer-modified bitumen are annually used in the construction of asphalt pavement worldwide, which induces serious volatile organic compounds (VOCs) emission and energy consumption associated with high working temperatures. To achieve cleaner production of high-performance bitumen, this study investigated the feasibility of using liquid isocyanate-based additive in bitumen modification. In comparison with the conventional styrene–butadiene–styrene (SBS) modified bitumen, mechanical and performance-related properties of isocyanate-modified bitumen were examined for practical application. The VOCs inhibition and energy consumption reduction mechanisms were interpreted based on the experimental and quantum-chemical investigations. The result shows that bitumen modification occurs through isocyanate's reactions with bitumen components. Compared to the widely used SBS-modified bitumen, at least a 20 °C reduction in bitumen production temperature, a 60% reduction in VOCs emission, and a 5% reduction in energy consumption can be achieved by isocyanate modification during the bitumen preparation, heating, and mixing processes. During isocyanate modification, both resins and asphaltenes are preferential targets for the chemical reactions with isocyanate. In this process, chemical crosslinking can occur at relatively low temperatures, which can also help reduce the existence of single polycyclic aromatic hydrocarbon (PAH) molecules and increase the difficulty of VOCs molecules' escaping. The findings not only provide a further understanding of the environmental performance of isocyanate-modified bitumen but also offer an impetus for future research.

Original languageEnglish
Article number133070
JournalJournal of Cleaner Production
Volume368
DOIs
Publication statusPublished - 25 Sep 2022

Keywords

  • Bitumen
  • Energy consumption reduction
  • GHG reduction
  • Isocyanate-based additive
  • Mechanism investigation
  • VOCs inhibition

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Building and Construction
  • Environmental Science(all)
  • Strategy and Management
  • Industrial and Manufacturing Engineering

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