Custom concrete mixes that suit the specific conditions/specifications of each project is becoming increasingly more common. These custom concrete mixes most likely won’t be available in our material library since they diverge from the standard mixes.
Concrete options that are currently available in our material library are a mix of the following specifications:
- Blends – Portland Cement, blast furnace slag (5%-100%) & fly ash (5% – 100%)
- Reinforcement – unreinforced, 1.0%, 1.5%, 3%
- Strength (MPa) – unspecified, 20, 25, 30, 35, 40, 50, 60, 80, 100
Besides getting an EPD to model the concrete in eTool, the other way to model these custom concrete mixes is to use our template customisation feature. eTool’s templates can be customised to address the issue of missing concrete blend mixes even though it isn’t as elegant as using what’s already available in the material library. To make the process easier, we have created a couple of custom concrete mix templates to assist users by providing a guideline to creating their own custom concrete templates. Further instructions on how to use these templates with links are as below.
Jump to the following sections in this post:
Detailed Custom Concrete Mix Template
For a detailed concrete mix template, please use the template linked below. You’ll also be able to add cement replacement items such as fly ash and blast furnace slag with this template, however you will also need to know the quantities for the other materials such as additives, aggregate, sand and water.
Poured Concrete – DETAILED CUSTOM CONCRETE MIX TEMPLATE (m3)
In order to edit the template, you’ll first need to clone the template so that it is a private template that you can work on.
After that, note the instructions on how to use this template provided in the template’s ‘Details’ tab.
Basically all you have to do is to enter each component in the custom concrete mix as a separate element in the template. Note that the category for this template is set to the ‘Substructure’ category, however all the individual concrete mix elements have been entered in multiple categories within the template. The template’s category needs to be updated once you’ve entered the quantities for your material inputs.
When you click into the ‘Substructure’ category (or any of the other categories highlighted above), you’ll find the following inputs:
Users are to enter appropriate quantities into relevant concrete elements under the applicable category to ensure that the total material volume adds up to 1m3 of concrete. You may change the units for each element as applicable (kg/m3 etc). Enter quantities only in elements where applicable.
The following inputs should also be left in default to maintain consistency with other concrete templates unless otherwise specified (i.e. HS2 specifications).
Simple Custom FA/BFS Concrete Mix Template
For a simplified concrete mix template where you only want to customise the fly ash or blast furnace slag content, please use the template linked below. You won’t need to know the quantities for the other materials such as additives, aggregate, sand and water as it will be based on industry averages depending on the MPa concrete you specify.
Poured Concrete – SIMPLE CUSTOM FA/BFS CONCRETE MIX TEMPLATE (m3)
In the same way as the above template, you’ll first need to clone the template so that it is a private template that you can work on. You have to enter the FA/BFS component as separate elements in the template. Note that the category for this template is set to the ‘Substructure’ category, however the custom elements have been entered in multiple categories within the template. The template’s category needs to be updated after you’ve entered the quantities for your material inputs.
After you’ve cloned the template, you’ll need to know what your Portland cement content is which will depend on your concrete strength. Please assume worse case figures of the maximum OPC content as per the table below. For higher strength mixes, please refer to your structural engineer for advice.
Table 1
You need to add the appropriate poured concrete template that suits the concrete strength and category of the product you’re modeling. For example, if you want to create a custom FA/BFS concrete blend template for 40MPa concrete foundations, you’ll need to add the ‘Poured Concrete – Foundations, 40MPa (m3)’ template. You can also rename this nested template at this step by editing the ‘New Element Name’ field.
Next, click into the relevant category to edit your FA/BFS inputs. The nested template you’ve just added will provide typical industry average inputs for aggregate, sand & water while the ‘Removal of XX% OPC from standard concrete’ input will be where you enter a negative value to represent the cement replacement done by the fly ash and blast furnace slag.
Below is an example of how you’d model a 20% fly ash, 20% blast furnace slag 40MPa concrete mix. The calculations for the OPC/FA/BFS quantities will be based on Table 1 above which states that the maximum cement content for 40MPa concrete is 420kg/m3. 20% of 420kg is 84kg therefore the two FA & BFS inputs will be entered as 84kg. The total removal of OPC is 40% therefore this equals 168kg however you must enter this figure as a negative value to represent the removal of only the Portland cement’s impact from the nested template (the remaining 60% Portland cement plus other materials will remain).
The following inputs should also be left in default to maintain consistency with other concrete templates unless otherwise specified (i.e. HS2 specifications).
Final Notes
After you’ve finished creating your custom template, please remember to update the template details with your assumptions and notes so that other users of the template will know what you have changed in the template. You should also remember to rename your new custom concrete mix template and update the template category to reflect what has been added or edited.
