Abstract
A novel hydrophilic polyurethane (abbreviated as W-OH) was developed and applied as a sustainable sand-fixing material. This paper on the chemical sand fixation mechanism of W-OH discusses the adhesive force between the W-OH solid and sand particles. The solidification mechanism was investigated and the solidifying time was tested. And then the thickness and porosity of the W-OH sand-fixing layer were investigated. By scanning electron microscopy (SEM), the microstructure of the W-OH sand-fixing layer was examined. The hardness and compressive stress of the sand-fixing specimens were studied at W-OH different concentrations. Finally, the resistance to wind erosion of the W-OH sand-fixing layer was investigated by a wind tunnel test. The results demonstrated that the W-OH aqueous solution had an excellent affinity for water on the surface of the sand particles, and the adhesive force between the W-OH solid and sand was primarily hydrogen bonding, covalent bonds and physical absorption, such as Van Der Waals forces. W-OH is a prepolymer of hydrophilic polyurethane containing groups of -NCO that can quickly react with water and other groups containing active H. The W-OH aqueous solution solidified in the range of 2 min to 15 min. The solidifying time decreased with increasing temperature and concentration. Before solidifying it had a good permeability of sand and the formed sand-fixing layer had a thickness of 8 - 35 mm and a porosity of 25% - 8% at a spraying concentration of 2 - 10 L/m2. The hardness index of the sand-fixing layer was in the range of 21 mm to 28 mm and compressive stress was in the range from 0.21 MPa mm to 1.27 MPa, both of which increased linearly with W-OH concentration. Sand treated by over 3% W-OH concentrations showed excellent resistance to wind/sand erosion of more than 25 m/s.
Highlights
Due to global climate change and intense human activity, land degradation has become a serious problem, in ecologically sensitive arid and semi-arid areas; it is one of the most serious environmental and socioeconomic problems worldwide and a major threat to the sustainability of agriculture and economic development [1,2]
The results demonstrated that the W-OH aqueous solution had an excellent affinity for water on the surface of the sand particles, and the adhesive force between the W-OH solid and sand was primarily hydrogen bonding, covalent bonds and physical absorption, such as Van Der Waals forces
The results demonstrate that a W-OH concentration of 2% has a relatively poor resistance to wind erosion damage due to the weak solidification of the sand-fixing layer
Summary
Due to global climate change and intense human activity, land degradation has become a serious problem, in ecologically sensitive arid and semi-arid areas; it is one of the most serious environmental and socioeconomic problems worldwide and a major threat to the sustainability of agriculture and economic development [1,2]. The surface application of animal slurries or sewage has been suggested to be effective against wind erosion [7,8,9,10]. With the development of the chemical industry, an increasing number of sand-fixing materials were developed and applied to desert control. They were primarily natural and/or synthetic compounds [14,15,16,17]. The resistance to wind erosion of the W-OH sand-fixing layer was investigated in wind tunnel tests. The wind erosion modulus was measured and studied by setting the wind-sand flow velocity to 10 m/s, 15 m/s, 20 m/s or 25 m/s and the angle of incidence to 0 ̊, 30 ̊ or 60 ̊, respectively
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
