Carbon Footprint of Fly Ash

Transcription

1 Carbon Footprint of Fly Ash ASHTRANS Conference 7. September 2015 Claus Pade, Danish Technological Institute Concrete Centre;

2 Danish Technological Institute Stavanger Stockholm Hirtshals Gothenburg Aarhus Sønder Stenderup Odense Taastrup Warsaw Self-owned and not-for-profit More than 1,000 innovative employees, state of the art equipment and facilities as well as a strong global network.

3 Content Fly ash used for concrete production benefits Carbon Footprint of Fly Ash Concrete Centre for Green Concrete ( ) Carbon Footprint of Fly Ash Environmental Product Declaration of Fly Ash All experience presented is based on data from Danish fly ash!

4 Fly ash in concrete why? Lower cost at equivalent performance Fly ash is cheaper per unit volume than cement Better performance (at equivalent cost or even at lower cost) Lower heat development Reduced shrinkage Better flow properties (incl. stability) Improved durability, e.g. resistance to chloride ingress

5 Volumen Volume in paste Lower cost Exposure class X0: no requirements to composition only strength (low) 50% or more fly ash Slabs on ground (SCC) Blinding layers Etc. 100% 90% 80% 70% Fly ash concrete PC concrete cccccccccc v/c = 0.50 cccccccccc k-faktor cccc = % 50% 40% Vand 30% Flyveaske 20% 10% Cement 0%

6 Better performance Exposure class e.g. XS3: requirements to composition (max. fly ash) Max 25% fly ash in powder (FA/CEM = 1/3) in DS 2426 Highway bridges Marine structures Deep foundation

7 Carbon Footprint of fly ash concrete - DK Center for Green Concrete Environmental screening of Green concrete highway bridge (in Danish) Life cycle (50 years) CO2 inventory e-projekter/groen-beton-i.aspx

8 Carbon Footprint of fly ash concrete From a concrete composition point of view the carbon footprint of concrete is dominated by the carbon footprint of the cement. For severe exposure classes 1/3 of the cement may be replaced by fly ash according to DS From a performance based point of view higher replacement rates could probably be allowed. For non-severe exposure classes higher replacement rates are allowed; in X0 no limit exist. Significant carbon footprint improvement is achieved from replacing cement by fly ash In practice fly ash is in competition with other additions/powder (e.g. slag, limestone)

9 Carbon footprint in specifications Started to see carbon footprint in concrete specifications e.g. 400 kg CO 2 /m 3 for the Copenhagen Metro extention Cityringen (2010) 18-34% fly ash in the concrete most in deep foundation structures

10 VOLENTARY REGULATED Environmental Product Declaration Sustainability in construction works Product level CPR (DoP, CE-marking) Building level CPR and Eurocodes Declaration of Performance Product level e.g. Nordic Swan, EEC Flower, EPD Construction Product Regulation Building level e.g. DGNB, Bream Environmental Product Declaration

11 VOLENTARY REGULATED Environmental Product Declaration Sustainability in construction works Product level CPR (DoP, CE-marking) Building level CPR and Eurocodes Product level e.g. Nordic Swan, EEC Flower, EPD Building level e.g. DGNB, Bream

12 Environmental Product Declaration Standards and PCR Technical standards: ISO (LCA) ISO (EPD) (2006) EN (EPD for construction products) (2012) Product Core Rules (PCR) Product unit Service life Allocation procedures And a lot more

13 Environmental Product Declaration EN 15804:2012

14 Environmental Product Declaration EN 15804:2012, Tabel 3 Impacts

15 Environmental Product Declaration LCA (Life Cycle Assessment ISO 14044) Production Transport and construction Use End of use Extraction and/or production of raw material + Transport + Production process Waste management

16 Environmental Product Declaration EN 15804:2012

17 EPD in the Danish Concrete Industry Cradle to gate approach Included Excluded Concrete plant Construction site

18 EPD in the Danish Concrete Industry Published EPD s Ready Mix Concrete Industry average EPD s for 5 typical concrete mix designs can be seen on the website based on specific data and generic data (GaBI) Cradle to gate Prefab industry average EPD s for 6 typical prefabricated walls based on specific data and generic data (GaBI) Cradle to gate The EPD s for Danish Concrete Products are using a Danish EPD for Fly Ash in the calculations

19 2/3 from Portland cement Higher strength Severe exposure

20 Lower strength Non-Severe exposure

21 Environmental Product Declaration for Fly Ash - DK

22 Environmental Product Declaration for Fly Ash DK Carbon Footprint Cement: 800 kg CO 2 -ækv. Declared Unit = One tons of Fly Ash

23 Environmental Product Declaration for Fly Ash DK EPD Calculations based on: Fly Ash is a co-product according to the definition in the waste Directive from (2008/98/EC) article 5, which means The impact from production of fly ash shall be allocated, but can be neglected if processes is generating a very low contribution

24 Environmental Product Declaration for Fly Ash Gabi Data Carbon Footprint = 201 [kg CO2-Equiv]/[tons Fly Ahs] Allocation has been done makes a huge difference Declared Unit in the table = One kg of Fly Ash

25 Environmental Product Declaration Standardisation work in CEN TC/350 CENSustainability A guidance to of is under construction development works Allocation rules Guidance are discussed for the The 1,0 % cutt of rule is probably being changed implementation of EN

26 DTI Danish programme operator If you should be in need of a 3rd party verified EPD!