Sustainable steel bridge maintenance: SustaSustainable Sustainable steel bridge maintenance: The role of paint in a LCA A": inable steel bridge maintenance: The role of paint in a LCA": CEPE Annual Conference 2014 in Riga Dr. Irmgard Winkels – Sika Deutschland GmbH

Content Starting point Goal and scope Description of the study Results of three different scenarios Conclusions

Starting Point CEPE built up an LCI database for coatings raw materials and paint production models. A tool – called Eco Footprint Tool - was developed to calculate footprints of coatings based on this database Result: environmental data for 1 kg of liquid paint (cradle to exit gate)

Example for a footprint Impact categories Global Warming Potential or Carbon footprint (GWP)3385.1g CO 2 eq Ozone Depletion Potential (ODP)298.2μg CFC-11 eq Photochemical Ozone Creation Potential (POCP)1716.3mg C 2 H 4 eq Acidification Potential (AP)20.6g SO 2 eq Eutrophication Potential (EP)8317.9mg PO 4 eq Energy Content Non-renewable62.5MJ Renewable2.7MJ Waste Non-hazardous26g Hazardous11g Resource Consumption Non-renewable3.9kg Renewable6kg Water147.5kg

Protective Coatings sector group decision Use this LCI database and Eco Footprint Tool to demonstrate how coatings can affect the sustainability of coated goods Calculate the role of paint concerning the sustainability in steel bridge maintenance

Goal and scope Impact of varying coating thicknesses on the sustainability of a steel bridge Perspective of an infra-structure responsible department Functional unit: Building and maintaining a bridge on a rural road, passing over a motorway, for 100 years

Study and calculation Done by Ecomatter based on assumptions given by CEPE, e.g. durability of coating systems, duration of coating application and surface preparation

Alternative coating systems Coating system 1 Coating system 2 Coating system 3 Zinc rich epoxy80 µm MIO-pigmented intermediate coat, epoxy -120 µm80 µm MIO-pigmented intermediate coat, epoxy µm Acrylic urethane top coat120 µm80 µm Repainting period / maintenance interval 15 years25 years40 years

Scenarios Scenario 1: Full life cycle Bridge construction, disposal and maintenance, including traffic disturbances. Scenario 2: Bridge maintenanceMaintenance, including traffic disturbances. Scenario 3: Only coatings Only coating related emissions over the life cycle. Bridge Coating Steel Bridge Initial construction Re-routing of traffic Bridge disposal and end of life Bridge Maintenance Bridge Coating Scenario 1 Re-routing of traffic Concrete Scenario 3 Scenario 2

Use and maintenance Maintenance additional activities, equipment and transport have not been included in the model. ActivityType of roadDisturbanceTotal timePeriod Painting: Blasting + Primer coat Motorway and rural ARoad closure16 hWeekend night Painting: Intermediate coatMotorway and rural ARoad closure8 hWeekend night Painting: Top coatMotorway and rural ARoad closure8 hWeekend night Specification 1Specification 2Specification 3 Painting frequency6 times / 100 years3 times / 100 years2 times / 100 years Total time per activity (all coats)24 h32 h40 h Rerouting distance per activity km km km

Scenario 1: Full life cycle Results for a life time of 100 years: Carbon footprint (expressed as GWP: Global Warming Potential) Initial bridge construction and associated traffic is about 2/3 rd of the GWP The contribution of the coatings is ~ 1% of the GWP System 3: the best overall performance Similar conclusions for the other impact categories System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs

Conclusion Differentiation of coatings systems not possible Image courtesy of phanlop88 / FreeDigitalPhotos.net Closer look necessary

Scenario 2: Bridge maintenance Results for a life time of 100 years: Contribution of the coatings is ~ 2 % of the GWP Lower repaint frequency: less rerouting System 3: best overall performance, ~ 40% better GWP performance compared to system 1 Similar conclusions for the other impact categories System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs GWP

Scenario 2: Other Impact categories System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs TotalCoatingsTraffic

Scenario 2: Other Impact categories For all impact categories, system 3 has the best overall performance over the whole life cycle. In general traffic is the dominant factor, but coatings has a higher relative contribution to toxicity and depletion of elements (ADP). System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs Scenario 2: Other Impact categories

Scenario 3: Coatings only System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs TotalYear 0Year 10Year 20Year 30Year 40Year 50Year 60Year 70Year 80Year 90Year 100 GWP over Timeline (Moment when coating is applied) Results for a life time of 100 years: System 3: best overall performance Higher coating thickness: higher impact per application Higher impact of thicker coating specifications in YR0 is compensated over the life cycle by the lower painting frequency. Maintenance schedules are the main factor for the environmental impact of paints over the life cycle. Similar conclusions can be drawn when looking into other impact categories

Scenario 3: Coatings only System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs GWP Best results for system 3 again despite higher film thickness and higher number of layers.

The amount of coating per year and the road closure days per year are the main drivers of the system: The extra layers and additional time that is needed to coat the bridge (and reroute traffic) are compensated by the lower painting frequency in the chosen scenarios The extra layers give a better performance over the entire life cycle. Conclusions (I) System 1: 2 layer & 15 years System 2: 3 layer & 25 years System 3: 4 layer & 40 years Amount of coating (kg) / year 40,631,226,3 Closure days / year0,180,120,10

For all scenarios, System 3 has the best overall performance during 100 years period. Direct impact caused by coatings is not significant, compared to the full bridge construction as well as to the need to reroute traffic. Variations in traffic disruptions during maintenance cause the main differences between the three specifications. Although the relative impact from building the bridge may change, the trends as presented are valid for different bridge sizes (length and width) if they follow similar maintenance cycles. The sustainability of the bridge is strongly determined by the durability of the coating system. Conclusions (II)

Thank you

Annex I – Definition of the bridge and detailed value chain, including assumptions

Bridge definition A traditional composite twin-girder bridge is used to model the system (Sustainable Steel-Composite Bridges in built environment Handbook). The model represents a new bridge replacing an existing bridge on a rural road, passing over a motorway.

Bridge life cycle Raw materials Construction Use and maintenance End of life

Additional materials (waterproof layer, joints, bearings) and transport of materials have not been included in the model. Raw materials have been simplified to a reduced number of products. Raw materials Selected material (in the model)Original materials (in handbook)Amount Reinforcing steel, at plant Structural steel S355 N/NL, Reinforcement steel bars, steel S235, steel S235JR 168 tons Concrete, normal, at plantConcrete C35/45, concrete C25/30683 m3 Mastic asphaltAsphalt72 tons CEPE specificationsPaint class C4 ANV450 m2 Raw materials

Construction Construction equipment and transport of equipment have not been included in the model. Type of roadDisturbanceTotal timePeriod MotorwayRoad closure168 hWeekend night Equivalent rerouting distance (valid for all specifications) km

End of life Demolition, transport and inventory of materials have not been included in the model. Recycling is currently not included in the model (only disposal). End of life flows are derived from the raw materials lists. End of life of coatings is not included in the model. Selected material (in the model)Amount Disposal of reinforcement steel69 tons Disposal of reinforced concrete1.724 tons Disposal of asphalt72 tons

Annex II – Detailed results for all impact categories

Scenario 1: Full life cycle Other impact categories System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs

Scenario 2: Bridge maintenance Other impact categories System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs

Scenario 3: Coatings only Other impact categories System 1: 2 layer & 15 yrs System 2: 3 layer & 25 yrs System 3: 4 layer & 40 yrs