21.08.18

Foamrox reduces the greenhouse gas emissions

A Master Thesis at NTNU in Trondheim (Department of Civil and Environmental Engineering) concludes that the Foamrox technology clearly gives the lowest greenhouse gas emissions in water-proofing and frost protection of road and railway tunnels.

See the link to the Master Thesis below.

 

This Master Thesis deals with the four water and frost protection solutions that are used in Norwegian infrastructure tunnels today with a focus on greenhouse gas emissions. It also addresses a potential new solution for water and frost protection and assesses this against the existing solutions. It has only been seen in tunnels that are built in the traditional manner, i.e. with drilling and blasting. Tunnel drilling machines have other prerequisites for VoF and are not dealt with in this task. Infrastructure tunnels have become a concrete-intensive construction, and a lot of concrete is used to secure the tunnels after blasting by injecting cement, and a layer of approx. 8 cm of sprayed concrete is used to secure the tunnel for work where it is needed before water and frost protection is built. This leads to high greenhouse gas emissions, and this is what this task will look at. 

For the VoF solutions, greenhouse gas emissions in connection with the production of materials, transport and construction have been included. Maintenance of the solutions are not included. The lifespan is uncertain, but reasoned, estimated lifespans will be assessed against the solutions. The financial aspect is not considered.

Major differences have been observed with regard to the amount of emissions which concrete results in, and this is an uncertain item. On a general basis and not surprisingly, the solutions with the most concrete come out worst, with regard to greenhouse gas emissions. Separately, greenhouse gas emissions from other materials have little to do with the total. Transport to a construction site can have a great impact on greenhouse gas emissions, but if a local concrete supplier is chosen, the distances for concrete transport are normally short and greenhouse gas emissions correspondingly small. This is also something that one should think about when a concrete supplier is chosen either by the contractor or the client.

It turns out that the actual construction has little impact on greenhouse gas emissions seen in relation to the production of materials. If one is to choose one focus area to reduce greenhouse gas emissions, then one should look at the materials that are used and ways to reduce material consumption. For example, this can be done by choosing a VoF solution that uses little concrete. 

When separating CO2 emissions from the different solutions by estimated lifetimes for each solution, one can see that CO2 emissions level out. This means that the most concrete-intensive VoF has a longer lifespan, but the most concrete-intensive solution still emerges as the worst when it comes to greenhouse gas emissions spread out across the lifespan. The solution that has not been used in VoF before, namely Foamrox foam glass, is the solution that comes out best in just about all the results, and research into this material for use by VoF should be implemented. The solution with a sprayable membrane also comes out well in the results, but this requires that there is no running water when the membrane is sprayed on and works poorly in areas exposed to frost.

The ranking of the solutions from lowest to highest CO2 equivalent in this study with concrete CEM II is as follows:

1. Foamrox foam glass with either wall elements or a concrete leading edge

2. Sprayable membrane with a low amount of frost

3. PE foam with sprayed concrete and either concrete wall elements or concrete leading edge

4. Concrete elements throughout the entire wall

5. Fully cast wall. These are the solutions for road tunnels. The same order will apply to railway tunnels, but without wall elements or a leading edge for the solution with Foamrox and without the solution with PE foam, since these are no longer used in railway tunnels.

Publisher

NTNU

https://brage.bibsys.no/xmlui/handle/11250/2558599