Post on 02-Jan-2016
Introduction
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)
Conclusions from Vägverket
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
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
System boundaries Included production, transport and road construction
work.
Top layer not included (not influenced by choice of light weight materials).
User phase excluded (considered mostly related to the bitumen layer, and thus independent on filling material)
End of life not included What is real life time of new roads? Will there ever be reuse of the materials?
We have applied the same system boundaries as in Vägverkets report.
Assumptions (2)
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 m3 LWA is required for 1 m3 of packed road material
Transport Vägverkets assumption of weight-limited transport is changed to volume-
limited (110 m3/max 35 ton)
Return transport not included (assumed 100% utilized)
Assumed transport distance 200 km
Assumptions (3)
Construction work
Diesel consumption in construction work included
Assumed that escavated masses is disposed within 1 km
Data applied
For LWA, data from 1997 (Vägverket) has been replaced by new data from 1999
LWA Packedvolume(m3)
Producedvolume(m3)
tonnes/m3
weight(tonnes)
Vägverket 37 37 522 19,2Ourassumptions
37,4 41,1 260 10,7
% difference + 1 % + 11 % - 50 % - 44,3 %
Results: Consumption of materials pr. m road
In addition, consumption of sand in the road base is eliminated with the new profile
Results: Consumption of alternative materialsMerolätt Packed
volume(m3)
Producedvolume(m3)
tonnes/m3
weight(tonnes)
Vägverket 52,7 52,7 813 42,2Ourassumptions
48,5 53,4 760 40,6
% difference - 8 % + 1,3 % - 6,5 % - 3,8 %
EPS Packedvolume(m3)
Producedvolume(m3)
tonnes/m3
weight(tonnes)
Vägverket 30,6 30,6 100 3,06Ourassumptions
29,5 29,5 20 0,59
% difference -3,6 % -3,6 % -80 % -80,7 %Concrete 3,45
Results new LCA - Energy consumption
Energy Consumption
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
Production Construction Transport Total
MJ
/m r
oad
Bioenergy (recycled)
Fossil energy (recycled)
Hydropower (primary)
Bioenergy (primary)
Nuclear energy (primary)
Fossil energy (primary)
Results new LCA - Global warming potential
Global Warming Potential
0
500
1 000
1 500
2 000
2 500
3 000
3 500
Production Construction Transport Total
kg
CO
2-e
qu
iva
len
ts /
m r
oa
d
CO2 from recycled energy carriers
CO2-equivalents other than recycledenergy carriers
Acidification
0
2
4
6
8
10
12
14
16
18
20
Production Construction Transport Total
kg S
O2-
eq
uiv
ale
nts
/ m
ro
adResults new LCA - Acidification
Results new LCA - Eutrophication
Eutrophication
0
10
20
30
40
50
60
Production Construction Transport Total
kg O
2-e
qu
ival
en
ts /
m r
oad
Results new LCA - POCP
Photochemical Ozone Creation Potential (Smog)
0
100
200
300
400
500
600
700
800
900
1 000
Production Construction Transport Total
g e
the
ne
-eq
uiv
ale
nts
/ m
ro
ad
Results new LCA - Waste
Waste
0
2
4
6
8
10
12
Production Construction Transport Total
kg w
aste
/ m
ro
ad
Industrial waste
Hazardous waste
Results new LCA - comparison to previous LCA
Energy
0102030405060708090
100
Vägverket*) Our results
GJ
/ m r
oad
Bioenergy (recycled)
Fossil energy (recycled)
Hydropower (primary)
Bioenergy (primary)
Nuclear energy (primary)
Fossil energy (primary)
*) Electricity recalculated to consumption of hydro power and nuclear energy
Results new LCA - comparison to previous LCA
Environmental impacts, relative to consumption of LWA
0 %
20 %
40 %
60 %
80 %
100 %
Re
lati
ve
val
ue
s
Vägverket
Our results
Results- Comparison between alternatives
Primary fossil energy
0,00
50,00
100,00
150,00
200,00
250,00
300,00
lwa merolätt eps
GJ
/ m r
oad
Vägverket
Our results
NB: Figures for Merolätt and EPS not based on new LCAs
Results- Comparison between alternatives
GWP
0100020003000400050006000700080009000
lwa merolätt eps
ton
CO
2 e
qu
ival
en
ts
Vägverket
Our results
Results- Comparison between alternatives
Waste
0,0020,0040,0060,0080,00
100,00120,00140,00160,00180,00200,00
lwa merolätt eps
kg Vägverket
Our results
Results- Comparison between alternatives
Acidification
0
10
20
30
40
50
60
70
lwa merolätt eps
kg S
O2-
eq
uiv
ale
nts
Vägverket
Our results
Discussion
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
Inclusion of the bitumen/asphalt layers would decrease the relative differences between the light weight materials
Sensitivity for difference in transport distance is highest for Merolätt, lowest for EPS