Experimental Study on the Micromorphology and Strength Formation Mechanism of Epoxy Asphalt During the Curing Reaction

Experimental Study of the Factors Influencing the Performance of the Bonding Interface between Epoxy Asphalt Concrete Pavement and a Steel Bridge Deck

The bonding between pavement and a steel bridge deck is a key component affecting the structural integrity of steel deck pavement and delamination is a major cause. The bonding interface of steel deck pavement was systematically investigated to evaluate the interactive influences of factors, such as the air void of the asphalt concrete pavement, the surface roughness of the steel deck, the thickness of the zinc-rich epoxy primer, and the waterproof bonding membrane, on the bond strength of the pavement interface, through simulated loading, brine immersion, pull-off, and interface observation experiments. The results show that a low air void (<3.0%) was a necessary condition for the corrosion resistance and bonding reliability of the steel deck pavement structure, and a zinc-rich epoxy primer provided an additional guarantee for corrosion resistance of the steel deck pavement; additionally, the combination of steel deck plate roughness in the range of 120–140 μm and zinc-rich epoxy primer thickness in the range of 80–110 μm led to a high bond strength, which was also conducive to the corrosion resistance of the steel bridge plate. The steel deck pavement structure should be designed through combinatorial optimization of multiple factors to create an integrated waterproof and anticorrosion bonding system.

Preparation and related properties of geopolymer solidified uranium tailings bodies with various fibers and fiber content

Uranium tailing ponds are a potential major source of radioactive pollution. Solidification treatment can control the diffusion and migration of radioactive elements in uranium tailings to safeguard the surrounding ecological environment. A literature review and field investigation were conducted in this study prior to fabricating 11 solidified uranium tailing samples with different proportions of PVA fiber, basalt fiber, metakaolin, and fly ash, and the weight percentage of uranium tailings in the solidified body is 61.11%. The pore structure, volume resistivity, compressive strength, radon exhalation rate variations, and U(VI) leaching performance of the samples were analyzed. The pore size of the solidified samples is mainly between 1 and 50 nm, the pore volume is between 2.461 and 5.852 × 10^-2 cm³/g, the volume resistivity is between 1020.00 and 1937.33 Ω·m, and the compressive strength is between 20.61 and 36.91 MPa. The radon exhalation rate is between 0.0397 and 0.0853 Bq·m^-2·s^-1. The cumulative leaching fraction of U(VI) is between 2.095 and 2.869 × 10^-2 cm, and the uranium immobilization rate is between 83.46 and 85.97%. Based on a comprehensive analysis of the physical and mechanical properties, radon exhalation rates, and U(VI) leaching performance of the solidified samples, the basalt fiber is found to outperform PVA fiber overall. The solidification effect is optimal when 0.6% basalt fiber is added.