Search

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]