Simulation test of short-term and long-term clogging of permeable pavement.

Permeable pavement is superior in functions such as reducing noise, improving traffic safety, and protecting urban water environment. However, contaminants on the pavement due to spillage of transported goods, deposits from vehicle wear and tear, and natural settlement can cause the risk of blockage when these contaminants enter the interior of the permeable pavement. Timely maintenance of permeable performance can effectively solve the degradation of environmental performance of permeable pavement caused by clogging. Consequently, exploring permeable pavement clogging patterns can support determining the timing of maintenance. In this paper, simulation clogging material gradations were formulated based on actual road clogging conditions. According to the self-developed permeable pavement clogging simulator, the clogging behavior of permeable pavement was comprehensively explored, taking external conditions, mix proportion, structural combination, and long-term clogging conditions into consideration. Moreover, the effect of external conditions on the clogging pattern was simulated by varying the rainfall intensity and clogging particle size. Furthermore, the effects of gradation, void rate, nominal maximum particle size, and the overwater section on the clogging resistance were investigated. The clogging-sensitive particle size under different structures was determined. It is demonstrated that the water head height is the crucial factor on the clogging behavior. Greater rainfall intensity and water head height lead to more severe clogging. The increase of nominal maximum aggregate size is beneficial to the anti-clogging ability of permeable pavement. Also, the clogging material with small particle sizes is more likely to cause structural clogging. Finally, the evaluation index of clogging level was put forward, which divides the clogging level of permeable pavement into mild, moderate, and severe. The research can support the rationalization, intelligence, and convenience of permeable pavement maintenance timing decisions. Meanwhile, there is key significance to the promotion application and performance maintenance.

Improving the Corrosion Resistance of Zn-Rich Epoxy Coating with Three-Dimensional Porous Graphene.

To improve the corrosion inhibition of zinc-rich epoxy (ZRE) composite coatings and shed light on the influence of the spatial structure of graphene fillers on the coatings' performance, three-dimensional graphene (3DG) and a conventional graphene sheet (G) were used to modify the ZRE composite paint, respectively. The effect of introducing the 2D G fillers on the anti-corrosion behavior of ZRE was studied comprehensively, and its optimal content was determined to be 0.5 wt%. Interestingly, it was found that, comparing with 2D graphene sheets, the corrosion resistance of the ZRE coating could be enhanced more significantly with incorporating even less 3DG. With introducing only 0.1 wt% 3DG, the corrosion current intensity of the resulting 3DG/ZRE coating was reduced to be about 1/10 that of the G/ZRE coating with the same graphene content and 27% of that of the optimized G/ZRE. The corrosion products of the coating were analyzed with the XRD technique. The results indicated that, in contrast to neat ZRE coating, Zn5(CO3)2(OH)6 was absent from the corroded 3DG/ZRE coating, confirming its improved long-term anti-corrosion performance. The porous interconnected framework and high crystallinity of 3DG could contribute to not only its facilely mixing with epoxy resin, but also its effective incorporation into the conductive network of zinc micro-flakes, thus enhancing the corrosion resistance of its ZRE coating at a lower content. The innovative technology to improve the anti-corrosion performance of the ZRE coatings via using the 3D graphene fillers should be capable to be extended to other 2D fillers, such as MXenes.