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Published byPatience Nichols Modified over 9 years ago
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Road case - Svensk Leca
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Introduction q The Swedish National Road Authority (“Vägverket”) has performed LCA of three alternative light weight materials for road construction: Leca LWA Merolätt (biproduct from steel production) EPS (expanded polystyrene)
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Conclusions from Vägverket q Environmental loads: Mainly from energy consumption related to production of materials (for Merolätt, also transport) Construction of road is of minor importance, independent of material EPS >> LWA >> Merolätt Difference between Leca and Merolätt smaller than between Leca and EPS. Reuse or energy recovery after demolition of road may substantially reduce impacts from all 3 alternatives
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Purpose of our work Perform an LCA of an LWA road construction, based on new, realistic assumptions Compare the results of the new LCA with those in the report from Vägverket, and discuss the differences Evaluate how the new assumptions might influence the results of the comparison
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System boundaries q Included production, transport and road construction work. q Top layer not included (not influenced by choice of light weight materials). q User phase excluded (considered mostly related to the bitumen layer, and thus independent on filling material) q End of life not included What is real life time of new roads? Will there ever be reuse of the materials? q We have applied the same system boundaries as in Vägverkets report.
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Functional unit q 1 metre road length of chosen profile
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Assumptions (1) q Road profile: (illustrations)
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Assumptions (2) q Material densities Vägverket: Applied dimensional density to calculate material needs and transport We have applied dry densities to calculate material needs and transport We have assumed that 1,1 m 3 LWA is required for 1 m 3 of packed road material q Transport Vägverkets assumption of weight-limited transport is changed to volume- limited (110 m 3 /max 35 ton) Return transport not included (assumed 100% utilized) Assumed transport distance 200 km
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Assumptions (3) q Construction work Diesel consumption in construction work included Assumed that escavated masses is disposed within 1 km q Data applied For LWA, data from 1997 (Vägverket) has been replaced by new data from 1999
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Results: Consumption of materials pr. m road In addition, consumption of sand in the road base is eliminated with the new profile
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Results: Consumption of alternative materials
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Results new LCA - Energy consumption
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Results new LCA - Global warming potential
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Results new LCA - Acidification
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Results new LCA - Eutrophication
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Results new LCA - POCP
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Results new LCA - Waste
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Results new LCA - comparison to previous LCA *) Electricity recalculated to consumption of hydro power and nuclear energy
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Results new LCA - comparison to previous LCA
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Results- Comparison between alternatives NB: Figures for Merolätt and EPS not based on new LCAs
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Results- Comparison between alternatives
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Discussion q Merolätt is a by-product of iron production. Environmental loads from Merolätt is based on economic allocation Changed economic value will influence the results heavily q Inclusion of the bitumen/asphalt layers would decrease the relative differences between the light weight materials q Sensitivity for difference in transport distance is highest for Merolätt, lowest for EPS
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Conclusions q New results show much smaller differences between the 3 alternatives than in Vägverkets report q The chosen change in road profile had minor importance for the results - similar volumes of light weight materials applied q Main difference in results due to new values for material densities
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