Research and development of high-performance geotextiles
According to the Research of Grand View Research(GVR), a well-known market research institution in the United States, the global market size of geotextiles in 2018 was about 4,751.8 billion square meters, and it is expected to reach 7,611 billion square meters by 2025, with an expected compound annual growth rate of 7.0%. The civil construction industry and geosynthetic materials industry are also constantly developing, geotextiles are gradually transforming into a key construction material essential in geotechnical engineering, and become basic materials in the fields of basic transportation facilities, water conservancy projects, landfill, urban municipal construction and so on.
In recent years, China has increased the development of polypropylene spinning clay cloth. A new type of high strength polypropylene spunbonded needled nonwoven geotextile (HPP geotextile) has been developed by domestic enterprises. Compared with ordinary PP geotextile, HPP geotextile has the advantages of high strength and good filterability. Deng Zongcai et al. from Beijing University of Technology conducted an experimental study on the aging resistance and corrosion resistance of HPP geotextile to provide further reference for its popularization and application. The results show that HPP geotextile has better heat resistance to oxygen aging, acid resistance, alkali resistance and water soaking resistance than PP geotextile.
The main methods to improve the performance of geotextile include adding additives, chemical modification and compounding. The use of additives to make up for the performance defects of geotextiles is a common method, but a large number of additives also pollute the environment to a certain extent. Modification research on geotextiles, such as further improving the strength and degradation resistance of geotextiles, is an important means to expand the application range of geotextiles and increase the added value of geotextiles. The results show that covalently grafted chitosan or cysteine onto acrylic modified PP geotextile can make the geotextile have the ability to capture heavy metals during drainage or filtration.
The research and development of high performance composite geotextile materials is of great significance to the development of civil engineering level. Li Xinyue et al. used polyester and low melting point fibers as raw materials to produce needled composite geotextiles, and used high density polyethylene (HDPE) and ethylene - vinyl acetate copolymer (EVA) as main raw materials to produce drainage plates by rolling suction process. Finally, geotextile filter membrane and drain plate core were hot-fused to prepare the excavated composite drainage material. The tensile strength of the geotechnical composite drainage material is greater than that of the monomer material before the composite, and it has a high water flow.
High performance geotextiles for industrial fiber raw material performance requirements in a variety of applications must be very durable, therefore, the selected industrial fibers need to have a high degree of stability, creep resistance, and low shrinkage, ultra-high strength or high modulus properties. Composite geotextile is usually a mixture of a variety of fibers, they combine the respective functional properties of different materials, to find suitable high-performance fibers has been an important research direction for high-performance geotextiles. The strength and modulus of inorganic fibers such as glass fiber, basalt fiber and carbon fiber are obviously higher than that of synthetic fiber. However, due to the high production cost, the large-scale application of inorganic fibers in geotextiles is limited. Glass fiber composite geotextile is made of glass fiber woven base fabric and staple fiber needled nonwoven fabric. It has the characteristics of high water permeability, excellent filtration resistance, wear resistance and so on. Basalt fiber geotextile has the advantages of environmental protection and high temperature resistance.
