If artificial sand is used, it is necessary to exploit large quarries, arrange many production lines and the cost is much higher than natural sand, according to the Prime Minister.
On March 1, the Prime Minister answered questions from National Assembly delegate Nguyen Huy Thai, National Assembly delegation of Bac Lieu province, about the solution of using artificial sand to replace natural sand for transportation projects in the Mekong Delta.
According to the Prime Minister, the demand for filling and foundation materials for projects in the Mekong Delta is currently very high. The 4 key expressway projects currently under implementation need about 56 million m3, not to mention the demand for sand materials for foundations for other projects invested by local authorities.
If artificial sand is used to completely replace natural sand, it is necessary to exploit very large quarries as well as arrange many new production lines to meet the demand and the cost is much higher than natural sand.
"It is not feasible to apply this solution to completely replace natural sand in the Mekong Delta," the Prime Minister said. Therefore, artificial sand is only prioritized for use in a few items with small volumes such as the production of asphalt concrete, cement concrete, etc.
Sand mining on rivers in the Mekong Delta. Photo: Ngoc Tai
In order to promptly meet the sand source for construction projects in the Mekong Delta, the Ministry of Transport has implemented a pilot project to use sea sand instead of river sand. The results show that sea sand in Tra Vinh province meets the technical requirements for roadbed construction, and sea sand/salty sand can be used to build roadbeds in saline conditions similar to the pilot area.
However, according to the Prime Minister, the pilot project is only being implemented on a small scale, the design scale is lower than the highway, the quality of sea sand has only been studied for one area, the standards and regulations on salinity for crops and livestock are not yet complete. Therefore, the widespread use of sea sand to build highways needs to be further piloted and expanded in projects with higher scale and design levels as well as piloted in different conditions and environments for comprehensive assessment.
The Ministry of Natural Resources and Environment has also completed part of the Mineral Resources Assessment Project, serving the exploitation of sea sand, meeting the needs of filling highway projects and urban and transport infrastructure in the Mekong Delta. Accordingly, the quality of sea sand in the 0-10 m water area of Soc Trang province meets the requirements for roadbed filling materials according to TCVN 9436:2012. The province and the Ministry of Transport are completing the exploitation procedures to serve the pilot expansion construction.
Regarding the solution of building expressways on viaducts in the Mekong Delta instead of building expressways on weak soil, the Prime Minister said that he has assigned the Ministry of Transport to study. However, solutions to build viaducts require a large amount of funding, about 2.6 times higher than building embankments.
In the context of limited investment resources, the sand material source in the Mekong Delta region is still capable of meeting the needs of the expressways being implemented in the 2021-2025 period, so the main projects are filling the foundation with sand; building viaducts for sections with weak soil depth, ensuring environmental criteria, flood drainage... and having reasonable investment costs.
Sand mining in the Mekong Delta is facing many difficulties due to the risk of landslides as well as the amount of sand flowing from the upper Mekong into Vietnam via the Tien River (Tan Chau, An Giang and Hong Ngu, Dong Thap) and the Hau River (Chau Doc, An Giang) being much lower than previously estimated.
Meanwhile, the demand for sand as a filling material in the Mekong Delta is currently very high, and the limited local supply has caused many key expressways to be at risk of being behind schedule. For example, the 110km Can Tho - Ca Mau expressway requires 18.1 million m3 of sand, but only nearly 1.5 million m3 (8%) has been supplied, causing the project to be delayed by 3 months.
Viet An
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