To investigate the mechanical properties of graphene (G) and calcium silicate hydrate (C-S-H) composites in different directions, molecular dynamics (MD) simulations and experiments were used, and the effects of temperature, loading rate, and graphene defects were also investigated. The experimental results show that the addition of graphene can improve the flexural, compressive, and tensile strength of the composite. The results of molecular dynamics simulation show that the addition of graphene in x and z directions can enhance the tensile strength of G/C-S-H in three directions, while the addition of graphene in y direction can reduce the tensile strength of G/C-S-H. At the same time, the tensile strength of G/C-S-H decreases with the increase in temperature and increases with the increase in loading rate. Meanwhile, the mechanical properties of G/C-S-H can be improved using a certain concentration of monatomic vacancy defects, diatomic vacancy defects, and S-W defects.

Iron tailings-based ultra-high-performance concrete (UHPC) was developed using iron tailings as aggregates, with steel fiber incorporation ranging from 0% to 2.5%. This study investigates the effects of steel fiber dosage and curing age on the electrical, electrothermal, and thermal conductivity properties of iron tailings-based UHPC. A comprehensive evaluation protocol was implemented to quantify resistivity, electrothermal conversion efficiency, and heat transfer characteristics, providing a systematic understanding of the material’s multifunctional properties. Results demonstrate that steel fiber incorporation significantly reduces electrical resistivity, achieving optimal conductivity at 1.5% fiber content. Electrothermal analysis under a 60 V applied voltage revealed maximum heating efficiency (ΔT = 32.5 °C/30 min for UHPC cured for 7 days and ΔT = 8.0 °C/30 min for UHPC cured for 28 days) at 1.5% fiber content. Thermal conductivity measurements identified a non-monotonic relationship with steel fiber content, initially increasing and then decreasing, with maximum thermal conductivity observed at 1.5% fiber content. This trend aligns with the observed resistivity behavior, suggesting a strong correlation between electrical and thermal properties. Fiber distribution within the iron tailings-based UHPC matrix revealed that steel fiber dispersion significantly affects material properties, with 1.5% fiber content achieving optimal percolation network formation for electrical current flow and heat transfer.

To address the dual challenges that conventional asphalt pavements are prone to softening and rutting under elevated summer temperatures while also exacerbating the urban heat island effect, this study proposed a composite modification strategy for asphalt mixtures using purified diatomite (PD) and titanium dioxide (TiO ₂ ). The effects of PD dosage on the fundamental properties of the asphalt binder and the thermal conductivity of the mixture were systematically investigated. The pavement performance, thermal-insulation capacity, and resistance to light-induced high-temperature softening of PD–TiO ₂ composite-modified asphalt mixtures were comprehensively evaluated, and the underlying synergistic mechanism was elucidated. The results showed that the penetration and ductility of asphalt decreased monotonically with increasing PD content, whereas the softening point and rotational viscosity increased monotonically, with an apparent performance inflection occurring at a PD dosage of approximately 15%. PD–TiO ₂ composite modification significantly enhanced the high-temperature rutting resistance, moisture stability, and light-induced softening resistance of the asphalt mixture. In particular, compared with the control group, the P2T3 formulation (15% PD + 3.5% TiO ₂ ) exhibited increases of 74.9% and 266.7% in Marshall stability and dynamic stability, respectively. PD and TiO ₂ synergistically established a dual thermal-barrier mechanism, ranging from radiative reflection to conductive heat inhibition, enabling the P2T3 group to achieve an average temperature reduction of up to 5.9 °C. Based on the overall performance evaluation, the optimum dosages of PD and TiO ₂ were determined to be 15% and 3.5%, respectively. These findings provide a theoretical basis and technical support for the material design of high-performance thermally insulating asphalt pavements.

To address the rapid polishing and premature loss of skid resistance in conventional asphalt friction courses, as well as the weak bonding between waste ceramic aggregates and asphalt that compromises raveling resistance, this study developed a ceramic aggregate asphalt mixture incorporating TPS–SBS composite high-viscosity modified asphalt, denoted as T&S. The wear-retained skid resistance and raveling resistance of the mixture were systematically evaluated. Interfacial adhesion between the modified asphalt and ceramic aggregates was characterized using water-immersion adhesion and contact-angle tests. Mixtures with different ceramic aggregate contents were further investigated through laboratory-accelerated abrasion, immersion Cantabro particle loss, and torsional raveling tests. In addition, an empirical skid-resistance degradation model and a frictional impulse-based characterization model were established. The results showed that TPS increased the asphalt–ceramic aggregate adhesion grade from Grade 3 to Grade 5, indicating a marked improvement in interfacial adhesion. Mixture skid resistance increased with ceramic aggregate content. After 16 h of abrasion, the residual British pendulum number of the mixture containing 80% ceramic aggregates was 38.7% higher than that of the control mixture. However, a ceramic aggregate content of 40% was identified as a practical balance point between skid-resistance improvement and overall mixture performance under the present laboratory conditions. T&S-modified asphalt reduced both Cantabro particle loss and torsional mass loss by more than 40%, partly compensating for the interfacial and skeleton-interlocking limitations of ceramic aggregates. The proposed models achieved coefficients of determination (R²) greater than 0.997, indicating high fitting accuracy for the present laboratory data. The preferred mixture design was determined as 8% TPS and 40% ceramic aggregate, providing a promising technical pathway for the resource utilization of construction-derived waste ceramics in asphalt pavements.