In English

Low-carbon classification of concrete in Finland

A low carbon classification system for concrete has been developed in Finland. BY Low Carbon Classification has been created in cooperation with Finnish Concrete Association, Confederation of Finnish Construction Industries RT and Aalto University.

The target was to create a transparent, open system to classify concretes based on CO2-emissions. BY Low Carbon Classification does not limit competition between concrete suppliers in any way; a contractor selects a low carbon class for the whole project or for a structure. The concrete producers inform which BY Low Carbon Classes they have available for different types of concrete.

BY Low Carbon Classification contains 18 different types of ready-mixed concrete, 17 different types of precast element concrete and 5 different low carbon classes. Different strength classes qualify as different types of concrete and frost-resistant as well as salt-freeze resistant concretes as additional types. The reference level (GWP.REF) corresponds to the average CO2 emission level of each type of concrete. The values of the reference level are determined with the help of inquiries made among the Finnish concrete industries in the summer of 2021. The other classes (GWP.85, GWP.70, GWP.55 and GWP.40) are calculated from the reference level in 15% descending steps. The lowest class (GWP.40) corresponds to an emission level of 40% compared with the reference level. New classes can be added in the system in the future as needed.

The limit values of each BY Low Carbon Class are GWPtotal values presented as kg CO2e/m3 of concrete. The methods of Environmental Product Declarations are followed and phases A1…A3 are included. A web-based calculation tool has been created to calculate the GWPtotal values for different types of concrete. The calculation is based on the mix design of the concrete. The transportation of the raw materials is taken into account using the actual transportation distances. Also, the energy consumption and the amount of waste from concrete production are taken into account. Pre-determined specific CO2 emission values are used for each raw material, mode of transport and energy source. The specific emission values of cements will be updated annually because cement plays a major role in the CO2 emissions of concrete.

It is believed that BY Low Carbon Classification will boost the development of low-carbon concretes in Finland. BY Low Carbon Classification gives the concrete producer full freedom to choose the methods to reduce CO2 emissions.

Table 1. Types of ready mix concrete covered by BY Low Carbon Classification® and limit values of BY Low Carbon Classes. The values are GWPtotal values and include modules A1…A3. The values are given in kg CO2e/m3.

Type of concrete GWP.REF GWP.85 GWP.70 GWP.55 GWP.40
C20/25 210 180 145 115 85
C25/30 230 195 160 125 90
C30/37 255 215 180 140 100
C35/45 285 240 200 155 115
C45/55 320 270 225 175 130
C50/60 340 290 240 185 135

C30/37 – Air-entrained 290 245 205 160 115
C35/45 – Air-entrained 330 280 230 180 130
C45/55 – Air-entrained 375 320 265 205 150
C50/60 – Air-entrained 395 335 275 215 160

C30/37 P0 270 230 190 150 110
C30/37 P30 300 255 210 165 120
C35/45 P0 300 255 210 165 120
C35/45 P30 330 280 230 180 130
C35/45 P50 340 290 240 185 135
C45/55 P50 375 320 265 205 150

P0, P30 and P50 are salt-frost resistant concretes used in the concrete infrastructure

Table 2. Types of concrete used in precast concrete elements covered by BY Low Carbon Classification® and limit values of BY Low Carbon Classes. The values are GWPtotal values and include modules A1…A3. The values are given in kg CO2e/m3.

Product group Concrete GWP.REF™ GWP.85™ GWP.70™ GWP.55™ GWP.40™
Hollow-cores and floor plates C40/50 270 230 190 150 110
C50/60 295 250 205 160 120
C60/75 340 290 240 185 135

Frame products1 C35/45 315 270 220 175 125
C40/50 335 285 235 185 135
C45/55 350 300 245 195 140
C50/60 360 305 250 200 145
C55/67 375 320 265 205 150
C60/75 390 330 275 215 155

Other precast elements2 C30/37 290 245 205 160 115
C30/37 air-entrained 310 265 215 170 125
C35/45 320 270 225 175 130
C35/45 air-entrained 340 290 240 185 135
C40/50 350 300 245 195 140

Walls, white cement C30/37 505 430
C35/45 525 445
C40/50 555 470

1 Frame products: precast columns, precast beams, precast TT and HTT slabs
2 Other precast elements: wall panels, solid slabs, technical shafts, foundation elements, and lift shaft elements

Material in English:

BY Low Carbon Classification, Guideline Part 1: Background report

Article of Low Carbon Classification system in Betoni-lehti March 15th 2022 (in English).

Same article in Betoni-lehti in Finnish and with pictures.