Kuan Li

To further explore the influence of the filler/binder (F/B) ratio on the fatigue behavior of epoxy asphalt concrete (EAC), in this study, three typical F/B ratios are designed according to the EAC pavement of steel bridges in China, including 1.49, 1.95 and 2.48. The four-point fatigue behavior of the EAC with various F/B ratios was tested and analyzed. The results show that a higher F/B ratio leads a more rapid increase in the ratio of dissipated energy change (RDEC) during limited loading repetitions, as well as an increased likelihood of irreversible damage and a shorter fatigue life for the EAC. To ensure adequate fatigue performance of the EAC, it is recommended that the F/B ratio be controlled below 1.95.

The crystal structure of solid-state materials with unique lattices is considered one of the main factors determining physical properties, including superconductivity. Materials with honeycomb lattices have inspired intense research interest for their novel properties. A previously unknown compound, Ta4CoSi, are discussed herein and its crystal structure and superconducting properties. It crystallizes in a CuAl2-type structure (space group P4/mcm, No. 124) with the lattice parameters a = b = 6.17755(7){\AA} and c = 4.98443(8) {\AA}, featuring honeycomb networks of Ta-Ta in (110) plane. Superconductivity is observed below the critical temperature of 2.45 K, while lower and upper critical magnetic fields are 9.86 mT and 0.84 T, respectively. Experiments and theoretical calculations show that the honeycomb lattices significantly influence the superconducting properties. This material may thus provide a new platform for investigating the exotic superconductivity of honeycomb networks.

A novel cold-mix epoxy (CME) concrete was developed to meet the urgent demand of quick maintenance in long-span steel deck pavement. Considering that the CME is a thermosetting resin, a differential scanning calorimeter (DSC) was employed to evaluate the curing behavior of the CME binder. Dynamic mechanical analysis (DMA) was used to investigate the viscoelasticity of the CME binder. The semicircular bending test and the three-point bending test were used to evaluate the crack resistance of CME concrete. Long-term performance was investigated by comparing the fatigue behavior of the CME concrete and hot-mixed epoxy asphalt (HMEA) concrete. The results showed that the curing reaction order of CME is similar to that of HME (hot-mixed epoxy) and the activation energy of CME is slightly higher than that of HME which means that the reactivity of the latter is higher. The bimodality that occurs in tanδ curve means that there are two phases existing in the CME and HMEA microstructure, while the secondary phase ensures that the CME and HMEA have good damping behavior. CME concrete has a better crack resistance than HMEA concrete at low temperature, and a similar crack resistance compared with HMEA concrete at high temperature. From the residual ratio of flexural stiffness after 1 million load cycles, the CME concrete shows better fatigue resistance than the HMEA concrete.