---From the 12th (2019) plastics and composite pipeline industry development exchange conference, the report on new progress of composite sand pipe made by Li zhuogqiu, a famous expert in composite industry and professor of Wuhan University of Technology
With the advantages of excellent mechanical properties, good designability, antifouling, light corrosion resistance and good sealing, GRP sand pipe is widely used in drinking water transmission pipe, sewage collection and transmission pipe, municipal water supply and drainage pipe, sea water transmission pipe and other underground pipeline fields.
Among them, the service life of the pipeline has been concerned at home and abroad. National standard GB / t21238-2016 points out that HDB, Sb and other parameters are extrapolated from (long-term performance test) regression curve to 50 years, while the international relevant standards (BS iso10467-2018, iso10639-2017) have clearly pointed out that the minimum design service life is 50 years, and the recommended design service life in practice can reach 100 years. Although China's FRP sand pipe industry has developed for nearly 40 years, there is still a certain gap between the current situation of domestic industry and the world's advanced level.
Professor Li mentioned that in the process of determining the long-term cyclic bending strain corrosion sb experimental scheme under the condition of constant displacement and corrosive medium, it was found that the long-term performance curve similar to flowtite could not be obtained by using the resin commonly used in China's FRP Industry (flowtite is an international company that conducted the long-term performance test of FRP pipes earlier). After repeated tests, it was not until the vinyl ester resin of Huachang polymer of East China University of science and technology was selected as the lining of the pipeline sample that the long-term strain corrosion sb value was successfully obtained. It is concluded that the selection of scientific and reasonable resin and fiber (such as vinyl ester resin, ECR and ect fiber) is the key.
Experimental process chart
Future pipe is an international large-scale continuous winding glass fiber reinforced plastic sand pipe company. Its products are made of vinyl ester resin from Huachang company from the inner lining to the structural layer. The submarine glass fiber reinforced plastic pipe is a special vinyl ester resin for Huachang sea water resistance. The designed service life of the sand pipe produced by the company is far longer than 50 years.
For the sewage pipeline, even a few enterprises still have such a misunderstanding: the sewage pipeline can choose the poor resin, resulting in some quality accidents. In recent years, some FRP pipeline enterprises are faced with the dilemma of production stoppage. In addition to the current raw material prices and other factors, the impact of these quality accidents is not unrelated.
Large diameter GRP sand pipe has a unique advantage in the application of plastic pipes for underground infrastructure, especially in the construction of large diameter underground sewage pipes in cities and towns with a hundred years plan. As long as the materials are properly selected, the designed service life of the pipes can reach 100 years. This is incomparable with other large caliber pipes. In the field of sewage pipes, some excellent enterprises use vinyl ester resin to make sewage pipes, which has reached the 100 year design service life recommended by international standards.
In a word, the design service life of 100 years is the future development trend of GRP pipes. Scientific use of high-quality component materials will help to improve the market competitiveness of GRP pipes.
(Dapeng, Yuyang)
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