LANZHOU, March 3 (Xinhua) -- Whenever sandstorms are mentioned, people often think of air pollution and strong wind erosion damage to buildings and traffic lines. A study by Chinese researchers has proposed a new insight that moderate wind and sand erosion can actually make the surface of materials more "solid."
Researchers have recently investigated the interface performance of wind- and sand-eroded concrete in desert environments and have proposed scientific evidence to improve concrete reinforcement methods, said the Northwest Institute of Eco-Environment and Resources (NIEER) under the Chinese Academy of Sciences.
In collaboration with researchers from the NIEER and Lanzhou Jiaotong University, this new study has been published in the journal Composites Part B: Engineering. It proposes mechanisms and reinforcement strategies for wind- and sand-eroded concrete infrastructure using carbon fiber-reinforced polymer (CFRP).
Concrete infrastructure in desert environments is subject to continuous wind and sand erosion, which accelerates its degradation. When reinforced with CFRP, such structures often exhibit uneven surface damage caused by erosion, according to NIEER researcher Liu Benli.
"Comparing with previous studies, which mostly focused on ideal flat interfaces, our study simulated different wind-sand environments by combining mechanical tests with microscopic analysis. Our study has, for the first time, proposed, from a mechanical perspective, the mechanism that moderate abrasion can form a microstructure conducive to the bonding of the reinforcing layer," Liu said.
He explained that, in a more vivid description, the process was similar to a sculptor carving out rough textures on stone for subsequent reinforcement. The moderate impact of wind and sand can also "carve" tiny grooves into the material's surface, providing natural "handles" for coatings or protective materials and significantly enhancing interfacial bonding.
The study results showed that, overall, sand erosion increased the interface ultimate bearing capacity of CFRP-concrete specimens by 31 percent and increased surface roughness by a factor of 10 compared with uneroded specimens.
Moreover, the study team developed predictive models for interfacial bearing capacity and the bond-slip relationship that incorporate abrasion effects, which showed good agreement with experimental data.
"Therefore, our study provides a scientific basis for the assessment and reinforcement design of damaged concrete structures in desert environments," said Zhang Kai, associate professor at the School of Civil Engineering, Lanzhou Jiaotong University.
"More importantly, the study has for the first time achieved a quantitative correlation between environmental conditions and interface performance. It means that engineers can precisely predict the load-bearing capacity of materials based on the intensity of wind and sand," Zhang said.
"It makes it possible for scientifically utilizing sandstorms as 'natural power' to sustain those sectors," he added. ■
