Prime Minister answers questions about the solution of using artificial sand to replace natural sand

In Document No. 153/TTg-CN dated March 1, the Prime Minister answered questions from National Assembly delegate Nguyen Huy Thai, National Assembly Delegation of Bac Lieu province.

Questioning content of National Assembly delegate Nguyen Huy Thai: “One of the solutions that the Government and the Prime Minister have directed to implement in the coming time is: Immediately remove difficulties and obstacles regarding material sources, especially in the Mekong Delta.

Accordingly, mining capacity will be increased if safety is ensured, the time for granting mining licenses will be shortened, and post-regulation licensing will be rectified; research on using sea sand as filling material for immediate use after the pilot results are available will be urgently completed, and at the same time, a plan for building viaducts will be studied to limit the use of filling materials and increase the ability to adapt to climate change will be studied.

According to experts, there is an alternative solution to natural sand, which is artificial sand. Could the Prime Minister please let us know whether the Government is considering this solution and whether it is feasible to apply this solution in the Mekong Delta?

Regarding the above issue, the Prime Minister replied: Implementing the Resolution of the 13th National Party Congress, the Government and the Prime Minister are resolutely directing the implementation of investment and construction of transport infrastructure projects in general and expressways in particular, in which ministries, branches and localities are required to focus on removing obstacles to promptly provide materials for projects, especially sand sources for embankment in the Mekong Delta, as well as researching materials to replace natural sand.

Currently, the demand for materials used for filling and embankment for transportation projects in the Mekong Delta region is very large. The 4 key expressway projects currently being implemented alone have a demand of about 56 million m3, not to mention the demand for sand materials for embankment for other projects invested by local authorities.

Although the reserves of river sand materials have been identified by localities and basically arranged enough resources, however, the exploitation and supply capacity has not met the material demand according to the progress of project implementation, because if the exploitation capacity increases too much, it will lead to riverbank erosion, affecting social life in the area. In addition, the Mekong Delta 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 of Transport, Construction, Natural Resources and Environment, and Science and Technology to focus on researching solutions to apply alternative materials nationwide in general and in the Mekong Delta region in particular.

The solution of using artificial sand to replace natural sand for traffic construction projects has been used by the Transport sector for many years in areas lacking natural sand resources.

The Mekong Delta region is the main area that uses sand as roadbed material with a very large demand as mentioned above.

If using artificial sand 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.

Therefore, applying this solution to completely replace natural sand in the Mekong Delta region is not feasible, so priority should only be given to replacing natural sand in some items with small usage volume such as: production of asphalt concrete, cement concrete...

To ensure timely supply of sand for construction projects in the Mekong Delta, the Ministry of Transport has implemented a pilot project to use sea sand instead of river sand, organized monitoring and supervision, and established a ministerial-level council to evaluate the pilot results.

The pilot results show that: sea sand in Tra Vinh province meets the technical requirements for making automobile roadbeds. Sea sand/salty sand can be used to build automobile roadbeds for the lower roadbed area (K95) in 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 that of the highway, the quality of beach sand has only been studied for one area, and the standards and regulations on salinity for crops and livestock are not complete.

Therefore, the widespread use of sea sand materials for road construction needs to be further piloted and expanded in projects with higher scale and design levels as well as piloted in different natural and environmental conditions for comprehensive evaluation.

At the same time, the Ministry of Natural Resources and Environment has deployed and completed part of the project "Evaluation of mineral resources, serving the exploitation of sea sand, meeting the needs of filling highway projects and traffic and urban infrastructure in the Mekong Delta."

The project has assessed the quality of sea sand minerals in the 0-10m water depth area of ​​Soc Trang province (area B1, area 250km2) to have quality that meets the requirements for roadbed filling materials according to the provisions of TCVN 9436:2012; assessed the mineral resources of sea sand for construction materials of level 333 + level 222 at 680 million m3, level 222 resources are 145 million m3, area B1 is eligible for immediate transfer to the exploitation unit according to Resolution No. 43/2022/QH15 dated January 11, 2022 of the National Assembly.

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 implement exploitation procedures to serve the pilot expansion construction.

The study of building a highway on a viaduct in the Mekong Delta region instead of building a highway directly on weak ground is also a solution that the Government and the Prime Minister have directed the Ministry of Transport to request consultants and relevant agencies to seriously and comprehensively study the technical, economic, social and environmental aspects right from the investment preparation stage to compare and decide such as: using an viaduct for the entire route; extending the bridge over the river to reduce the height of the bridge head; handling subsidence with soil cement piles, load-reducing floors... to minimize the use of sand for filling, shorten the waiting time for subsidence, increase stability, and minimize risks during construction and operation.

However, viaduct construction solutions require large funding sources (currently, the cost of constructing viaducts is about 2.6 times higher than the embankment solution).

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 deployed in the 2021-2025 period, so the main solution is to use sand to fill the foundation; handle the embankment section at the bridge head with cement-soil piles, load-reducing floors; build viaducts for sections with large weak soil depth, ensuring environmental criteria, flood drainage, etc. and with reasonable investment costs.

To prepare for investment in upcoming projects, the Prime Minister has directed the Ministry of Transport to research and comprehensively report on solutions for developing traffic in the Mekong Delta region and plans for filling materials for project implementation.

PV