40th LCA Discussion Forum Why to assess gravel use – and which gravel? Arthur Braunschweig, Dr. oec. HSG, E2 E2 Management Consulting AG Wehntalerstr. 3, CH-8057 Zurich, Tel. +41 44 368 50 20, Fax +41 44 368 50 21 www.e2mc.com, e2post@e2mc.com
Content LCA DF 40 Gravel! - The questions - Results & Learnings from a new LCA study on recycled vs. natural gravel / aggregate and concrete - Thoughts on gravel assessment E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 2
Starting points LCA DF 40 Gravel! - Gravel is a resource - Gravel is in soil. Getting access needs machinery etc. Their effects are obviously included in LCAs - But for the resource itself, nobody cared - neither NGOs nor in LCA. - The Swiss BAFU, however, cares (as do other authorities): It asked to include 'gravel use' into UBP'06 - What are the first learnings? What should stay, what should be improved`? E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 3
Experience with the 'gravel ecofactor': The aggregate LCA 2010 LCA DF 40 Gravel! - LCA for Aggregate ('Gesteinskörnung'; Kies etc.) and Concrete (Kytzia et al., 2010, publ. pend.; commissioned by Holcim (CH) AG) - Question: Is it environmentally useful to use recycled aggregate in concrete? - � LCA for aggregate types 4 LCAs: � LCA for concrete with & without recycled aggregate � LCA for a generic building project � LCA for a Swiss region - Background of the study: Environmental building standard 'Minergie P-Eco' asks for 25 % recycled aggregate in concrete, if available in the area. Holcim wanted a scientific basis for their internal further strategy discussion and for the public discussion on concrete recycling. E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 4
The aggregate LCA 2010: Key results LCA DF 40 Gravel! - Basic results ("Ökobilanzen zum Einsatz rezyklierter Gesteinskörnungen in Betonen"; Kytzia et al., 2010, publ. pend.) - Using recycled aggregate -- reduces 'gravel use' and 'ecosystem damage', as well as the waste stream -- for low quality concrete reduces the airborne impact categories (GWP, AP, respiratory effects) -- for high quality concrete does not influence to a relevant extent energy use and airborne impact categories (GWP, AP, respirat. Damage) - Reason for the latter: high quality concrete with recycled aggregate needs a higher cement content. - Transport of recycled aggregate becomes very relevant @ > 30 km E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 5
The aggregate LCA 2010: Results on high quality concrete (1) LCA DF 40 Gravel! Gravel use Concrete C 30/37 Land use C 30/37 Respiratory effects C 30/37 Acidification C 30/37 GWP C 30/37 Energet. Resource use C 30/37 0% 25% 50% 75% 100% 125% 150% Gravel production Cement prod. Concrete prod. Recycled aggregate production E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 6
The aggregate LCA 2010: Results on high quality concrete (2) LCA DF 40 Gravel! Concrete C 30/37 (25% recycled aggregate = "RC") Gravel use Concrete C 30/37 RC Land use C 30/37 RC Respiratory effects Note: C 30/37 RC 30/37: 320 kg cement RC Acidification C 30/37: 303 kg cement C 30/37 RC GWP C 30/37 RC Energet. Resource use C 30/37 0% 25% 50% 75% 100% 125% 150% Gravel production Cement prod. Concrete prod. Recycled aggregate production E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 7
The aggregate LCA 2010: Results on low quality concrete LCA DF 40 Gravel! Comparison for 0 et 100 % RC; both w/ 200 kg cement Gravel use ('Magerbeton') Lean Concrete Lean Concrete 100% RC Land use Lean 100 % RC Respiratory effects Lean 100 % RC Acidification Lean 100 % RC GWP Lean 100 % RC Energet. Resource use Lean 100 % RC 0% 20% 40% 60% 80% 100% 120% Gravel production Cement prod. Concrete prod. Recycled aggregate production E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 8
Sensitivity Analysis: Cement content, Recycled aggreg. content LCA DF 40 Gravel! 5% 5% Cement content: 4% 4% Effect on 3% 3% emissions 2% 2% No effect on 1% 1% resource use 0% 0% 0 0 3 3 6 6 9 9 12 12 15 15 Increase in cement content (based on 303 kg = 100 %) 0% 0% Recycled 10% 10% ‐ ‐ Energy res. 20% 20% ‐ ‐ aggregate content: GWP 30% 30% ‐ ‐ 40% 40% ‐ ‐ AP Effect on Energieressourcen 50% 50% ‐ ‐ Respirat. Treibhauseffekt gravel use & land 60% 60% ‐ ‐ Land use ecosys. dam. Versauerung 70% 70% ‐ ‐ Gravel use Atemwegserkrankungen use (?) 80% 80% ‐ ‐ Landnutzung 90% 90% ‐ ‐ Kiesabbau No effect on 100% 100% ‐ ‐ emissions Recycled aggregate share of total aggregate E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 9
Gravel / Aggregate production: New (ranges) and RC (generic) LCA DF 40 Gravel! RC, fixed Gravel use Site 1 Site 2 Land use Respiratory Data sources: effects ‐ RC, fixed: adapted from ecoinvent RC, fixed Site 1 Acidification ‐ Site 1, Site 2: Site 2 Holcim GWP RC, fixed Energet. Site 1 But what does a combined Resource use Site 2 0% 100% 200% 300% 400% 500% 600% 700% 800% assessment look like? Production Moving land and gravel Other transports E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 10
Regional assessment LCA DF 40 Gravel! Assumptions: - All torn down concrete is used for RC (except 5 % waste), .. - .. either for direct (loose) application, e.g. as foundation, road bed, etc - .. or in (RC-)concrete Natural Scenario: B) Recycled Aggregate Aggregate Kies ‐ Betonwerk werk Concrete Demand in the region Angebot in der Region A) Recycled 1.079 Mio. t Beton/ Aggregate 2.2 Mio. m 3 Beton Betonabbruch Gebäude Schotter/ 3.6 Mio. t Gesteinskörnung Strasse Deponie E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 11
Regional assessment (w/ all old concrete used) LCA DF 40 Gravel! RC into concrete With these Gravel use assumptions, it RC aggregate direct use does not mat- Land use ter a lot HOW recycled Respiratory RC into concrete aggregate is effects RC aggregate direct use used. Acidification As long as it IS used. GWP Energet. RC into concrete Resource RC aggregate direct use use 0% 25% 50% 75% 100% 125% 150% Natural gravel production Recycled aggregate production (*) Concrete production Concrete production Transports new gravel Transports recycled aggregate Transports concrete E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 12
UBP'06 results in gravel and concrete LCA (Kytzia, 2010; 1) LCA DF 40 Gravel! UBP for gravel and RC-aggregate Aggregate Aufbereitungs- aggregate mobile installation Recycled anlage, inkl. production Landnutzung fixed installation Kiesabbau Gravel prod. Site 2 Site 4 Natural Gravel Baumaschinen Machinery Site 3 Site 1 Other andere Transporte transports ecoinvent 0 5 10 15 20 25 30 35 40 UBP / kg For aggregates, the gravel ecofactor dominates the assessment. E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 13
UBP'06 results in gravel and concrete LCA (Kytzia, 2010; 2) LCA DF 40 Gravel! For concrete, the Lean concrete gravel effect is very Lean concrete relevant. with 15 % recycled granulate Lean concrete with Lean Concrete, high RC-content 100 % RC granulate creates less environ. 0% 25% 50% 75% 100% impacts Gravel production Concrete production For high quality con- Cement production Recycled aggregate production crete, the gravel ecofactor's contribu- tion is significant. RC ‐ Beton C30/37 But the overall result shows only small C30/37 differences. 0% 25% 50% 75% 100% E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 14
UBP'06 results in gravel and concrete LCA (Kytzia, 2010; 2) LCA DF 40 Gravel! Vergleich UBP regionale Betrachtung On a regional Szenario B: scale: RC into concrete IF all waste Szenario A: concrete is RC as loose used, it aggregate does not 0% 25% 50% 75% 100% 125% matter if it is used in Gravel production Concrete production Cement production Recycled aggregate production concrete or Transports natural Transports recycled aggregates as loose aggreg. Transports concrete aggregate! E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 15
Gravel in the UBP'06 method LCA DF 40 Gravel! New in UBP'06: Ecofactors Why an ecofactor for gravel in (weighting factors) for: UBP'06? - Fresh water - 'a resource sui generis , necessary - Diesel soot ('Russ') for most building processes - Diocins and Furans - 'not all gravel is accessible' - Radioactive emissions to water - 'is a specific case of land use' - PAK - scarcity: current use = critical use - Benzo(a)pyrene - Endocrine substances - Land use - Gravel use Is this a convincing case for inclusion into LCIA? What abouts other stones, gold, diamonds? E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 16
Why & how put 'gravel use' as an environm. impact category? LCA DF 40 Gravel! WHY GRAVEL: WHAT SAFEGUARD SUBJECTS? � 'resource sui generis' � cleaning of rain water, ground water � some land (shapes) used for gravel sites are protected HOW TO INCLUDE: � as a spearate impact category? � include the gravel (soil) functions in similar impact categories (double counting? No function – resource, landscape, ground water – is covered fully in existing impact categories)? � leave out? E2 / DF-LCA 40 / Why to assess gravel use / 20.04.10 / page 17
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