2024, the Ministry of Housing and Urban-Rural Development said that China would renovate more than 100,000 kilometers of underground pipelines every year in the future. Underground pipeline network includes municipal public pipelines such as water supply, rainwater, sewage, reclaimed water, natural gas, heat, electricity and communication to meet the needs of life and production within the city. According to the statistical yearbook of urban construction published by the Ministry of Housing and Construction at the end of 2023, the length of urban water supply, drainage, natural gas and heating pipelines in China is 1.103 million kilometers, 914,000 kilometers, 980,000 kilometers and 493,000 kilometers, respectively. Generally speaking, natural gas and heating pipelines usually use steel or plastic pipes, and cement products are mainly used in urban water supply and drainage pipelines. Therefore, we focus on the cement demand that may be brought about by urban water supply and drainage pipeline renovation.
First, the renovation of old pipelines is the main task, and the amount of renovation in Jiangxi and Shanghai may be relatively large
, as can be seen from the Implementation Plan for the Renovation of Urban Gas Pipelines (2022-2025) issued by the General Office of the State Council in May 2022. At present, the transformation of underground pipeline network is mainly aimed at all kinds of aging pipelines and facilities with backward materials, long service life, potential safety hazards in operating environment and non-compliance with relevant standards and specifications. Specifically, gas and heating pipelines with an operating life of more than 20 years and water supply and drainage pipelines with an operating life of more than 30 years will be the focus of transformation. On the premise of ignoring the historical demolition and renovation, the total scale of underground pipeline network renovation in China may be about 420000 kilometers, of which the scale of urban water supply and drainage pipeline renovation is about 215000 kilometers, accounting for about 50% of the total renovation.
Figure 1: Length of various underground public pipelines in China from 1982 to 2022 (10,000 km)
Data source: Cement Big Data (https://data.ccement.com/)
At present, The application of various concrete pipes in the pipeline industry accounts for about one third, and the mainstream products include prestressed concrete cylinder pipe (PCCP), prestressed concrete pipe (PCP), reinforced concrete pipe (RCP) and self-stressing concrete pipe (SPCP). Taking the prestressed concrete cylinder pipe as an example, the amount of cement used in the manufacturing process is about 400-600 kg/m. According to this calculation, the cement demand brought by the transformation of urban water supply and drainage pipelines is about 8-10 million tons per year, accounting for only about 0.5% of the cement market. By calculating the leakage rate of public water supply pipelines (leakage water volume/total water supply),
we can infer the importance of the transformation task of old underground pipelines all over the country. In terms of provinces, the leakage rate of water supply pipelines exceeds the national average in 13 provinces. Among them, the leakage rates of Jilin, Heilongjiang and Liaoning are in the top three, reaching 23.1%, 19.3% and 16.7% respectively; Guizhou, Inner Mongolia, Hubei and Shanghai are in the second echelon, with the leakage rates above 15%; Jiangxi, Beijing and Chongqing are in the third place, with the leakage rates of 14.9%, 14.8% and 14.3% respectively. Considering the financial pressure in some provinces, it is expected that underground pipeline renovation projects may be promoted faster in Hubei, Shanghai, Jiangxi and Beijing provinces and cities in the short term.
Figure 2: Leakage rate of public water supply pipelines by province in China in 2022 (%)
Data source: Cement Big Data (https://data.ccement.com/)
II.
In addition, according to the "14th Five-Year Plan for the Implementation of New Urbanization", in the process of promoting the renovation of old urban pipeline networks, the construction of underground comprehensive pipeline corridors should be coordinated according to local conditions. Underground comprehensive pipeline corridor refers to the tunnel built underground in the city for centralized laying of various municipal public pipelines. The construction of underground comprehensive pipeline corridor is helpful to solve the problems of repeated excavation of pavement, dense overhead line network and frequent pipeline accidents, and is an important content to speed up the completion of the short board of urban underground infrastructure. From a practical point of view, in the face of natural disasters such as typhoons and waterlogging in recent years, the comprehensive pipeline corridors in some cities have initially shown their role, which has improved the city's security and disaster response capabilities. The construction of underground comprehensive pipe galleries
in China has been piloted since 2015. By the end of 2022, a total of 7094 kilometers of underground comprehensive pipe galleries have been built nationwide, with an average annual construction length of more than 1000 kilometers. Since the 14th Five-Year Plan, the construction of underground comprehensive pipeline corridors has slowed down due to imperfect system standards, lack of overall planning of projects and high financial pressure on construction, operation and maintenance. Considering the actual situation, it is estimated that the average annual construction volume of the comprehensive pipe gallery will be about 500-1000 kilometers in the future.
Figure 3: Construction volume of underground utility tunnels in China from 2015 to 2022 (km)
Data source: Cement Big Data (https://data.ccement.com/)
According to the statistics of China Cement Network Big Data Research Institute, The concrete consumption for the construction of underground comprehensive pipe gallery is basically about 10,000-20,000 m3/km. According to this rough estimate, the annual cement demand brought by the construction of underground comprehensive pipe gallery is about 5-10 million tons, which also accounts for a small proportion in the cement industry.
To sum up, in the future, the cement consumption generated by the reconstruction of old underground pipelines and the construction of comprehensive pipe galleries will be about 10-20 million tons per year, which is equivalent to 0.5% -1.0% of the national cement output in 2023. Underground pipeline network transformation can effectively reduce the probability of disaster events and improve the quality of life of residents, which is an important part of future urban renewal action. However, due to the limited proportion of cement products in the pipe industry and the slowdown in the construction of underground pipe galleries, the actual pulling effect on cement demand is relatively limited, and it is difficult to change the downward trend of national cement demand.
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