Material consumption and embodied energy

Project Targets
  • 15% Reduction in material consumption across the Project lifecycle
  • 100% Timber is reused/recycled or from sustainable sources e.g. AFS/FSC
  • 10% Cement replacement material (by mass) in concrete
  • 10% Recycled materials in road and subbase (including Reclaimed Asphalt Pavement)

Concrete, steel, asphalt and aggregates are the main materials used in construction. JHCPB is focused on investigating low carbon alternatives to reduce emissions related to intensive material consumption in tunnelling and civil construction works. During the review period JHCPB used 135,520 m3 of concrete, 9,047 tonnes of steel and 75, 313 tonnes of quarry materials in construction. Project to date values are provided below.

The project has used ~1300m3 of low carbon concrete, achieved over 50% cement replacement and recycled material in road base/subbase and purchased 93% of the total timber from sustainable sources.

The Project is committed to reducing material consumption across the Project lifecycle by 15%, and reducing the embodied energy of construction materials, through the implementation of the following initiatives:

  • Use of glass sand as a replacement to virgin sand within flowable fill applications in tunnelling works
  • Use of bespoke low carbon concrete mixes which incorporate a higher percentage of Supplementary Cementitious Materials (above 50% cement replacement) in R53 applications
  • Use of Emesh recycled plastic fibres in lieu of traditional reinforcing steel in footpaths
  • Research and development into the use of geopolymer concrete
  • Beneficial reuse of tunnel spoil on site for civil works e.g. backfilling of declines and shafts
  • Optimised design to reduce re-work and material usage including the removal of pavements in ancillary tunnels
  • Utilisation of materials with Environmental Labels (Environmental Product Declaration)
  • Use of recycled materials in road base and retaining walls
  • Investigating circular economy initiatives within our waste streams