Low-emission MOF modified rubberized asphalt: Preparation, performance and malodorous compounds release behavior

Rubberized asphalt (RA) has a serious problem of malodorous gas emission during production and construction, while the existing deodorizers have low adsorption efficiency and are ineffective in inhibiting odorous components. This paper establishes an odor index model based on odor threshold and component concentration, combined with principal component analysis (PCA), to identify and quantify malodorous-causing substances in VOCs emitted from RA. A chromium-based metal-organic framework (MOF) MIL-101 was synthesized to achieve efficient and directional inhibition of malodorous-causing substances. It is found that key malodorous compounds such as thiophene, dimethyl trisulfide, butyraldehyde, methacrolein, 2-methylpropanal, 2-methylbutanal, and alkylated benzenes were precisely traced and confirmed as major contributors to asphalt odor. In addition, the high surface area, hierarchical pore structure, and unsaturated Cr³ ⁺ sites of MIL-101 contributed to its selective adsorption capacity, which achieved an 84.77 % reduction in VOCs emissions and suppressed 61.1 % of key malodorous. Simultaneously, the rigid MIL-101 framework reinforces the asphalt matrix, improving rutting resistance by 57 % without compromising low-temperature flexibility. Considering mechanical performance, emission control, and economic feasibility, the optimal MIL-101 content was determined to be 8 ‰. This study provides a scientific basis for the use of MOF materials in VOCs suppression and odor control, offering a novel and practical strategy for sustainable rubberized asphalt pavement applications.