Concrete with recycled aggregate

  • Hi,

    Has anyone modeled the life cycle impact improvement of concrete containing Recycled Aggregate? One of my projects in Australia has proposed to use that and would like to understand the impact. There seems to be no template associated with this at the moment.

    Any help/input on this is very much appreciated!


    Hi Jeewei,

    In order to model what you’re proposing, you’ll need a concrete template that has split the concrete into the individual component parts (portland cement, aggregate and sand). I’ve created a very simple test template here for your reference.

    Note that in this template I’ve included two nested templates for the concrete – one with normal aggregate and one with recycled aggregate for you to compare the difference it makes. As you can see the improvement is marginal and doesn’t account for any compensation that may be required for the concrete mix using recycled aggregate.

    If would still like to model this recommendation for your project/client, you’ll have to create new templates (of course without doubling up on the concrete in the one template like this test template) using this methodology as we don’t have this type of concrete template in our library.

    You’ll need to make sure that you’re using the correct cement/sand/aggregate ratios required for the concrete specification for your project. You’ll also need to check with a structural engineer for feedback on whether it is a straight forward swap between the two types of aggregate or if that affects the concrete strength.

    Hi Fei,

    Thank you for your response and test.
    How about a concrete mix with recycled aggregate and supplementary cement use (ie BFS or PFA)? I thought of using the above methodology to create my own concrete template but there is no BFS or PFA material to select from. Any help on this is much appreciated.


    Hi Jeewei, there is a material for BFS in the material library however that material is for the the whole concrete with %BFS in it rather than with separate components so you won’t be able to model what you want with that methodology. You could perhaps try it this way however there are limitations as this template is using the IMPACT dataset which means some material options won’t be available on the Australasian dataset. However it should give you a gist of what I mean.

    There is however a risk with DIY templates such as what you’re trying to do due to there being lots of other factors which can affect the strength and quality of the concrete making it possibly not a viable ‘mixture’ if that makes sense? If the mixture you’re trying to model actually exists as a product, I would strongly advice getting the manufacturer to provide an EPD which you can then enter into eToolLCD. That will probably be the most reliable & accurate way to model that product.

    Hi, Following up on this topic again.
    Understand currently eTool has LCI database for concrete with different % of SCM replacement (either Fly Ash or Blast Furnace Slag).
    Projects are starting to adopt Ternary Blend (ie composition of OPC, FA and BFS) to balance Sustainability, Shrinkage, durability factors. Any chance eTool will develop or allow projects to customize different concrete mix design to capture their environmental benefits in LCA? ISCA’s IS Materials Calculator allows such detailed assessment. Is it possible that we adopt IS Material Calculator’s results and incorporate into eTool? Hoping such feature to be considered as the industry is moving towards lowering embodied carbon.

    Hi Jee Wei,

    I would still recommend going the EPD route with such products.

    You should however make a Feature Request of what you mentioned on our support site though! The feature with the most votes will be pushed up on the priority list. So after you have created your request, please go through the requests currently on the list and vote for other features that you wish to see expedited. 🙂

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