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The research evaluated the properties of cold-mixed epoxy asphalt (EA) and cold-mixed epoxy styrene–butadiene–styrene (SBS)-modified asphalt (ESA) for paving steel-deck bridges. Compared with ESA, EA showed longer pot life and better processability at ambient temperature, as revealed by curing rheology analysis. The cured EA showed higher glass-transition temperature, superior thermal stability, tensile strength and elongation at breaking than ESA. These may be as a result of: (i) the high thermal stability of asphalt, (ii) the formation of a cross-linking network in the cured material, and (iii) the good compatibility between the epoxy resin and the asphalt. [ABSTRACT FROM AUTHOR]

High temperature and oxidation are two of the most critical factors that cause epoxy asphalt aging. This paper aims to clarify the variation of mechanical performance and structure of effect of cold-mixed epoxy asphalt (CEA) after thermal-oxidative (TO) aging. The mechanical properties of CEA were studied by tensile tests and dynamic mechanical analysis. The microstructure of CEA was studied by Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, SEM, and fluorescence microscopy. The results indicated that the tensile strength of CEA increased to 5.16 MPa, the elongation at break decreased to 50.3%, and the T g decreased significantly after TO aging. TO aging made the epoxy resin in CEA post-cure, oxidate, degrade and the cross-linked network break. Furthermore, the asphalt particles in CEA agglomerated and oxidized. [Display omitted] • ER underwent a post-curing reaction and degradation. • Asphalt underwent volatilization of the light components and an oxidation reaction. • Thermal-oxidative aging destroyed the original phase structure of the CEA. [ABSTRACT FROM AUTHOR]

The compatibility of cold-mixed epoxy asphalt (CEA) significantly influences its mechanical properties, primarily mediated by the epoxy group content within CEA. However, the feasibility and mechanisms for regulating the external epoxy group content to achieve optimal performance have yet to be explored thoroughly. Herein, soybean oil, epoxidized soybean oil, and epoxy-terminated hyperbranched epoxy resin (EHER) were used to construct CEA with different external epoxy group contents, and their effects and mechanisms on the compatibility and mechanical properties of CEA were investigated based on experiments and molecular dynamics simulation. Our findings suggest that maintaining an external epoxy group content between 8.4%∼11.4% in the CEA blend and below 12.17% in the cured CEA is crucial. These criteria can be met by adding no more than 5 wt% EHER. CEA with 3 wt% EHER exhibited the most balanced compatibility and mechanical properties, characterized by a pot life of 91 min, a tensile strength of 5.02 MPa, an elongation at break of 61.3%, and a tensile toughness of 1.58 MJ/m3. The presence of external epoxy groups increased the cohesive energy density and the solubility parameter difference between epoxy resin and asphalt prior to curing, forming a "sea-island" structure with varying particle sizes, primarily comprising small-sized particles. This structure was preserved post-curing, establishing a stable system with minor energy alterations. Simultaneously, EHER enhanced the molecular rigidity and uniformity of CEA, thereby improving its mechanical properties. It is recommended to relate epoxy group content in CEA blends with indicators of compatibility and mechanical properties, enabling better prediction. • Desirable performance is exhibited by CEA with no more than 5 wt% EHER. • ER provides strength and asphalt acts as a toughener in CEA. • The "sea-island" structure is preserved post-curing with minor energy variations. • Epoxy group content in blends has a high grey correlation with performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biodiesel is recommended to be preferentially adopted as an asphalt solvent. • Asphalt solvents with high boiling points and moderate solubility are recommended. • Asphalt solvents should ensure CEA form a "sea-island" network. • Most asphalt solvents were preserved in the cross-linked network. Cold-mixed epoxy asphalt (CEA) is mixed and cured at room temperature, requiring dissolving asphalt before preparation. It is essential to choose suitable asphalt solvents to prepare CEA with desirable performances. This paper prepared CEAs with five kinds of asphalt solvents, including diesel, biodiesel, 1,2-dichloropropane, trichloroethylene, and solvent naphtha. The rheological properties of the CEA were studied by Brookfield viscometry and bending beam rheometry, then tensile tests and dynamic mechanical analysis were performed to study the mechanical properties. The morphology of the tensile fracture profiles of CEA was observed through scanning electron microscopy. Recommendations for selecting asphalt solvents are as follows: (1) the solubility of the solvent should ensure the formation of sea-island structure in CEA; (2) the solvent should have a high boiling point and moderate solubility to ensure CEA desirable antiaging ability. As a result, biodiesel is recommended and preferentially adopted. According to the ion chromatography, the volatilization of solvents mainly occurred within 48 h during CEA curing, and nearly 60 % of solvents were "sealed" in the CEA, participating in the formation of the cross-linking network. [ABSTRACT FROM AUTHOR]