Artificial sand's price is too high
Questioning the Prime Minister, National Assembly delegate Nguyen Huy Thai asked: "One of the solutions that the Government and the Prime Minister direct to implement in the coming time is: Immediately remove difficulties and obstacles regarding material sources, especially in the Mekong Delta (Mekong Delta).
According to expert suggestions, there is an alternative to natural sand, which is artificial sand. So, has the Government considered this solution? Is it feasible to apply this solution in the Mekong Delta?
Regarding this issue, the Prime Minister said that currently, the demand for materials used for leveling and backfilling for traffic projects in the Mekong Delta region is very large, especially four key expressway projects are under construction. Deployment requires about 56 million m3, not to mention the need for sand materials to build foundations for other projects invested by local investors.
Prime Minister Pham Minh Chinh shared a discussion at the group in the program of the 6th session of the XNUMXth National Assembly, in which he shared many concerns about solving traffic infrastructure in the Mekong Delta (Photo: VGP/Nhat Bac).
The solution of using artificial sand to replace natural sand for traffic construction projects has been used by the transport industry for many years in areas with a shortage of natural sand sources. The Mekong Delta region in particular is the area that mainly uses sand as road embankment material with huge demand.
If artificial sand is used to completely replace natural sand, it is necessary to exploit large quantities of stone quarries as well as arrange many production lines to meet demand and the cost is much higher than that of artificial sand. with natural sand.
Why can't we increase river sand mining capacity?
Although the reserves of river sand materials have been identified by localities and basically enough sources have been arranged, the exploitation and supply capacity has not met the material needs according to the project implementation schedule.
In case of excessive exploitation capacity increase, it will lead to riverbank erosion, affecting social life in the region. Besides, the Mekong Delta region is an area greatly affected by climate change.
Therefore, to solve the shortage of construction sand materials for projects in the Mekong Delta region, the Prime Minister has directed the Ministries: Transport, Construction, Natural Resources and Environment, Science and Technology Focus on researching solutions to apply alternative materials throughout the country in general and the Mekong Delta region in particular.
Therefore, the Prime Minister said: "Applying this solution to completely replace natural sand in the Mekong Delta region is not feasible, so priority should only be given to using it to replace natural sand in some items with large blocks of sand. The amount of use is not large such as: producing asphalt concrete, cement concrete..."
To ensure timely supply of sand for transportation projects in the Mekong Delta, the Ministry of Transport (MOT) has implemented a pilot project to use sea sand sources to replace river sand, organizing monitoring, Monitor and establish a ministerial-level council to evaluate pilot results.
Pilot results show that sea sand in Tra Vinh province meets the technical requirements for roadbed construction. Sea sand/saline sand can be used to build roadbeds for the area below the roadbed ( K95) under saline conditions similar to the pilot area.
However, the pilot project has only been implemented on a small scale, the design scale is lower than a highway, the quality of sea sand has only been researched for one area, and the regulations and standards on salinity for with incomplete crops and livestock.
Therefore, the mass use of sea sand materials to build motorways needs to continue to be piloted and expanded in projects with higher scale and design levels as well as piloted in natural conditions. , different environmental conditions for comprehensive evaluation.
The current test construction section of sea sand embankment is the return road to provincial road 978, with a length of about 300m.
At the same time, the Ministry of Natural Resources and Environment has implemented and partially completed the project "Evaluation of mineral resources, serving sea sand exploitation, meeting the need for leveling highway and transportation infrastructure projects." traffic and urban areas in the Mekong Delta".
The project has evaluated the quality of sea sand minerals in the sea area of 0-10 m water in Soc Trang province (zone B1, area of 250 kmXNUMX).2) has satisfactory quality as road embankment material according to regulations
At the same time, the Ministry assessed mineral resources of sea sand as construction materials level 333 + level 222 to reach 680 million mXNUMX.3, resource level 222 is 145 million m3, B1 area is eligible for immediate transfer to exploitation unit.
The Ministry of Natural Resources and Environment has transferred the project results to the People's Committee of Soc Trang province and the Ministry of Transport. Currently, the Ministry of Transport is coordinating with the People's Committee of Soc Trang province to deploy exploitation procedures for the expansion pilot construction.
The solution to build a viaduct requires large funds
Regarding the study of building highways on viaducts in the Mekong Delta region instead of building highways directly on soft ground, this is also a solution that has been requested by the Government and the Prime Minister to request advice and consultation from the Prime Minister. Relevant agencies seriously and comprehensively research the technical, economic, social and environmental aspects right from the investment preparation step for comparison.
From there, decisions can be made such as using viaducts for the entire route; Extend the bridge across the river to reduce the height of the bridgehead; Handling settlement with soil cement piles, load-reducing floors... to minimize the use of sand for leveling, shorten the time to wait for settlement, increase stability, and minimize risks in construction and exploitation.
However, viaduct construction solutions require large amounts of funding (currently the viaduct construction cost is about 2,6 times higher than the foundation solution).
In the context of limited investment resources, the source of sand materials in the Mekong Delta is still capable of meeting the highways being implemented in the period 2021-2025, so the solution of sand embankment is mainly applied; Treating the bridgehead embankment section with soil-cement piles and load-reducing floors; Build viaducts for sections of the route with large soft soil depths, ensuring environmental and flood drainage criteria.... and has reasonable investment costs.
To prepare for investment in projects in the near future, the Prime Minister has directed the Ministry of Transport to research and report comprehensively on solutions for traffic development in the Mekong Delta region and plans for filling materials for implementing these projects. project.
