Skip to main content

Green Cement G#735 N#757

By 19 February 2014January 2nd, 2019Uncategorized

Green Cement

Green Cement


ECOCEM of Ireland’s marketing claim:

ecocem.png Green Cement  “the world’s most sustainable building material”

NGS’s Reaction:

‘Greenwash’, what evidence do you have for such a statement?

Whilst NGS promote GGBS wholeheartedly I could never say what you are claiming.

Half-truths and bad choice of words in places tells a very optimistic story.

When you tell the whole story then it is very different.

GGBS: Ground Granulated Blastfurnace Slag – Cement

EcoCem: The basis for such a claim is as follows:

Ordinary Portland Cement has a carbon dioxide footprint of approximately 900 kg’s of CO2/tonne

  • TopTrumps focuses on one issue at the expense of all others.

Our GGBS cement as certified by NSAI is 29 kg’s of CO2/tonne – see certificate here

  • TopTrumps you win
  • You have obviously been allowed to ignore most of the carbon and all of the impacts of the steel making process.
  • Ignore the energy: Top Trumps you win.
  • Not by you but by others before you.
  • The carbon was already released in the smelting process.
  • What fuel was used in the smelting and in the cement processing?

Hence when you use our GGBS cement instead of normal Ordinary Portland Cement you save over 800 kg’s of CO2/tonne of cement.

  • GGBS is rarely if ever used as a 100% substitution, 
  • nearer 36-65% depending upon application.
  • So adjust your figures to suit.

Our cement is 100% recycled – no natural virgin/primary materials are processed in the production

  • Your cement is not 100% recycled cement.
  • 100% of your material resources are a by-product or waste product from steel making, the residue left over when iron ore is smelted, steel melts out and the slag that floats to the surface is decanted and then milled to a fine powder that has cementitious properties.
  • Such by-products or waste products are classified as co-products and the carbon/dioxide and other impacts shared out proportionately.
  • In Life Cycle Assessments allocations based on economic value of all outputs
  • Cement is a valuable commodity so should attract a significant % of the impacts
  • The virgin aggregates making up the iron ore are all natural minerals.

Our cement reduces the production of harmful pollutants (similar logic to CO2 comparison)

  • If you ignore the release of harmful pollutant of the steel making process and the cement processing.

Our cement reduces the energy used in the production (similar logic to CO2 comparison)

  • If you ignore the energy of the steel making process and the cement production
  • This depends upon what fuel stocks that are used in the steel making and the cement processing.
  • Your cement is also transported using fuel and adding pollution, even if by train, worse by lorry.
  • Cement is not a building material, its always used with others as an ingredient of a mix, 
  • It’s building material is render, mortar or concrete, 
  • You need to consider the impact of the whole of the mix, cement, aggregates and water.
  • So add in the embodied energy and carbon and emissions and environmental impacts for all of them too.
  • and the making and transporting of the concrete

There are other savings

We are not trying to imply that it is greener than all materials

  • Yes you are, reread your simple statement. “The world’s most sustainable building material”
  • I do not know how to read that any differently than the ways you stated it.

but rather that the savings achievable on a building are greater than any other material that can be practically used.

  • Well that’s not what you said is it?
  • Say what you mean, 
  • mean what you say, 
  • no Greenwash.

For example it may not be possible to replace a 20 storey concrete/steel structure with mud or timber but by replacing concrete made with ordinary Portland cement with concrete made with Ecocem GGBS cement you will typically reduce the embodied CO2 of the structure by 25%.

  • Top Trumps you win
  • 25% or 20% for the cement only, what % for the concrete?
  • How does this reduce when you look as concrete not just cement?
  • Irrelevant comparison?
  • Nobody would consider building 20 storey in Mud, in the UK
  • Now you are adding steel into your equation.
  • You probably could replace the 20 storey building with CLTP panel construction.
  • CLTP: Cross Laminated Timber Panels

You will also get a structure that is stronger and more fire resistant.

  • More strength than is needed, excessive use of cement is common place.
  • More fire resistance than is needed
  • CLTP can achieve the required fire performance too.
  • CLTP timber also sequestrates carbon dixide during growth and locks it up in the material

If you use concrete made with our GGBS cement for bridges or marine structures you could expect to get a structure that will last twice as longer

  • Top Trumps you win
  • Twice as long as OPC? Or other material?
  • Timber and steel structures can and do last a very long time.

– if a structure lasts twice as long then only half the materials needs to be used over the design life.

  • Top Trumps you win, no that’s a rubbish argument
  • Your structure is twice as durable as it needs to be, you over designed it.
  • It will last twice as long as it is needed, then become a blot on the landscape
  • If the design life is 60 years design a 60 year structure,
  • If its made of timber or steel it too would be designed to have a 60 design life.
  • it will probably have excessive cement than is needed, excessive use of cement is common place
  • You will use the same amout of materials to build it now, whatever the life is
  • it probably would not be rebuilt
  • You will use some more material for a longer life concrete structure (extra cover to reinforcement)

The statement might seem strong

  • It doesn’t seem strong, it is strong, too strong, 

but we believe that as concrete is the second most widely used substance in the world after water, that anything that reduce the carbon dioxide footprint of concrete by over half will indeed bring really significant savings.

  • You previously said 25% (probably means
  • But now you are talking about concrete, not cement so its a different lower % than cement.
  • Check that you got your facts right.
  • If concrete is such a widely used material then any claims your sector makes need to be accurate.
  • Any claims your company makes need to be squeaky clean.
  • All you can claim is that GGBS is the greenest cement in the world if there is nothing better than it.
  • Non-limestone based cement may compete with it?
  • What about PFA cement?
  • Not so sure about furnace ash (see PFA)


  • Top Trumps?
  • Lime mortar, limecrete, lime render and lime screed are all optional alternatives with lower embodied energy
  • Cement based mortar make bricks unreclaimable
  • Cement render makes walls non-permeable to moisture vapour
  • Cement render destroys historic fabric
  • I could go on all day


  • Your company needs to be the greenest and using the cleanest fuel to make any particular claim.
  • Sticking your logo in front of the claim implied its your cement that is so wonderful
  • Have you compared your operation with all you competitors across the world?

I hope this helps clarify matters a little but I would be happy to speak with you about our message and how we might better deliver it

  • Unimpressed.
  • Read my notes and edit accordingly

Kind regards

David O’Flynn BEng MBA CEng MIEI


Business Development Manager

Ecocem Ireland Ltd. Third Floor, Portview House, Thorncastle Street, Ringsend, Dublin 4

Mobile: 00353 87 965 4891       Direct: 00353 1 678 1804

Tel: 00353 1 678 1800             Fax: 00353 1 678 1816

@doflynn David O’Flynn

What could you justifiably say about this material?

I think the following are too long and may still need to be justified with some number crunching but they feel safer statements than your current strapline.

  • © “Whilst concrete is the second most widely used material in the world after water, GGBS as an OPC replacement has the greatest capacity to improve the environmental impact of the construction industry globally”
  • © “OPC replacement with GGBS probably has the greatest capacity to reduce the environmental impact of conventional building than any other material choice”
  • © “GGBS cement has the lowest environmental impact of all cements”
  • © “Bagged blended GGBS & OPC cement probably has the greatest capacity to reduce the environmental impact of the SME builder and hence the conventional construction industry as a whole”
  • © “Its time for structural/civil engineers to ‘stop permitting and to start requiring’ the use of blended GGBS & OPC in all cement applications”.
  • © “Its time for specifiers to ‘stop permitting and start requiring’ the use of blended GGBS & OPC in all cement applications”.
  • © “Its time to ‘start specifying’ the use of blended GGBS & OPC in all cement applications”.

© BrianSpecMan aka Brian Murphy 31st January 2013 – 31st July 2013

© GBE NGS ASWS BrianMurphy
aka BrianSpecMan
31st January 2013 – 2nd January 2019

Leave a Reply