The comparison

The findings of this study are based upon the calculation of carbon emissions from:

■ Embodied raw material emissions
■ Transport of materials
■ Implementation fuels

■  Transportation of labour
■  Distribution and disposal

The Geobear method extends the lifetime of the existing asset, whereas the traditional method is a replacement.

Embodied raw material emissions

The embodied emissions have been calculated by multiplying the mass of each material by the correspondent carbon emission factor.

The emission factors used typically include, for each material: the extraction of the raw materials they are made of, their transportation, processing and distribution.

Transportation of materials

Geobear is based on an average supply distance by sea freight and truck to site.

Fuel emissions in transport and during works based on typical consumption. The precast concrete was modelled as sourced from the Netherlands, with remaining materials from within the UK.

Implementation fuels

The implementation fuels are higher for the geopolymer solution, over a 60-year period, as a result of the 10 treatments needed.

The fuel use is significantly higher for the traditional method, in the first year, due to the need to remove the concrete rail crossing prior to replacement. However, due to the Geobear treatment being repeated every 6 years, more fuel is required over the 60-year timeframe.

Transport of labour

Includes one HGVs and two vans, calculated to include transport to and from site for 1 of Geobear’s treatments.

For the traditional method, an equivalent distance to Geobear’s travel was assumed with two labourer’s vans, one van for the manual tamper, two HGVs (to account for the excavator and vibrating plate compactor), and a rail journey for the ballast profiler.

Emissions from disposal

DEFRA factors have been applied with the disposal quantities provided by Geobear.

The Geobear calculations also include the treatment emissions from inert material landfill.