Concrete and Type of Cement Mix

[graving]

In the context of designing a jetty exposed to severe marine conditions (exposure class XS3), I am considering a concrete mix design that meets the structural requirements and prioritises environmental sustainability. Having identified a concrete grade of C40 with a water-cement ratio between 0.35 and 0.4 as a potential fit, I seek recommendations on the most suitable cement mix or standards that address this. Will be interesting to hear your ideas. Thank you

 

[BulbTheBuilder]

XS3 and C40 sounds like you're using European code. It has been a while since I have used them. But values around C40 are typically design mixed and not the responsibility of the design engineer. Admixtures and higher-grade cementitious materials are used so I can't give an exact mix ratio.

For your structure, you should consider adequate concrete and size for durability. I believe EC2 covers that part

 

[graving]

Great, thank you!

 

[dik]

In Canada, you can spec a concrete mix design or leave this option up to the suppler. Typical spec options are: type of construction, f'c, cement type, max w:c, max slump, aggregate size, air content, and admixtures. For your use:
[ul]
[li]I would assume the C40 is 40MPa;[/li]
[li]you would specify the type of cement powder to be used depending on the requirement (this can be left to the supplier);[/li]
[li]you can set the w:c to 0.4 max;[/li]
[li]you can set the slump equal to 75 to 100 max, depending on what you are doing;[/li]
[li]max aggregate size can be set to 40mm, or larger if you can use it;[/li]
[li]air content can be set to 5% to 7%, depending on what you are doing; and[/li]
[li]admixtures can include the normal ones plus you can add a hydrophobic one to reduce the permeability.[/li]
[/ul]

In addition:
[ul]
[li]you have to take care of any rebar coating systems;[/li]
[li]make sure you have adequate concrete cover;[/li]
[li]you need sufficient bar spacing to reduce cracking; and[/li]
[li]make sure you have adequate consolidation for a dense cocrete placement.[/li]
[/ul]

We would normally leave the mix design to the supplier. The supplier should provide you with their mix design so you can review it (or have a good geotekkie review. Suppliers are often reluctant to provide this because they consider it proprietary. Have this as a specification requirement).


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So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik