By Ina Johanne Mønsted, October 2016
Traffic congestion, soaring property prices, severe pollution and rampant illegal construction. These are some of the challenges developing cities like Hanoi, Vietnam, are facing in the wake of booming growth and the resultant acute lack of housing.
Soft ground has made some of the city’s central areas uninhabitable. However, these derelict inner city areas will soon pulse with new life, now that the city has been chosen for a pilot project testing the Finnish UUMA2 programme.
UUMA2 (a Finnish acronym for eco-efficient material solutions and the commercialisation of earthworks with recycled materials) is a programme that aims to replace non-renewable natural resources with recovered materials in earthworks via techniques like mass stabilisation.
So far, a 200-metre stretch in an area once unfit for development has been stabilised in central Hanoi. This eco-friendly and cost-effective solution has not only increased the value of the land but also eased the housing problem. The soft soil does not have to be removed from the construction site, and replacement materials do not have to be hauled on site from great distances, all of which minimises the use of natural resources and the need for heavy transport.
Leena Korkiala-Tanttu, Professor of Geotechnical Engineering at Aalto University, Finland, is one of the researchers involved in the project. She explains the fundamentals:“By using cement or ash as binders instead of natural rock resources, for example, we can optimise the properties of our construction materials. Local soil conditions and climate mean the exact recipe is always project-specific, so our main focus is to gain a thorough insight into the properties of all the UUMA materials, so that we can create the best match in each particular case,” she says.
The binder and soil materials are acquired from surplus ground, industrial by-products and waste, as well as from mildly contaminated soil and materials from old earthworks. These can be used as they are or as components for replacing untouched rock material or improving soil properties.
Pilot projects lead the way
Ramboll Finland has developed the UUMA technology over the past 20 years. One of the major pilot projects is being conducted in Jätkäsaari, a former cargo port on the southern peninsula of Finland’s fast-growing capital, Helsinki. The area is now being transformed into a dense urban district that will house 17,000 inhabitants when finished in 2025.
“Through UUMA technology, areas like Jätkäsaari that are undeveloped due to difficult soil conditions can now be transformed into urban zones. Sediments from the nearby sea are used to stabilise the area, making the process cheaper and more eco-friendly,” says Marjo Ronkainen, Head of Unit, Environmental Geotechnics, at Ramboll Finland.
Many other cities worldwide are struggling with housing shortages, and developing urban areas neglected due to technical difficulties is key to solving the problem.
In Vietnam, ground stabilisation was an unknown method with no common standards for using the technology until the country got involved in the UUMA2 programme. Today, plans are in place for setting standards that will help make the technology more widespread.
“The UUMA2 programme has great potential for many countries that are struggling with few natural resources or resources of a low quality. For example, countries like the Netherlands, Russia and the Baltic countries could all benefit from this know-how and technique in the near future,” says professor Leena Korkiala-Tanttu.