Do Concrete Superplasticizers and Additives Reduce GWP?

What are the impacts on GWP of additives and superplasticizers in concrete?

Often the construction schedule requires that the structural compressive strengths (i.e., cure time) are not met until later, but early “set times” are required to begin other work. By including additives and superplasticizers I understand that the set time can be reduced allowing construction and staging to begin without marring the surface, but what are the impacts on embodied carbon of these measures?

There is a lot of information available that cement reductions should be the focus for low-carbon concrete, but not much on the GWP of additives or plasticizers. If we can speed up the set time, then longer curing times (e.g., 56 days) could be targeted and therefore the cement and GWP could be reduced. Is the addition of additives and plasticizers worth the reduced cement?

Would love to hear any resources or project specific experience.

I have wondered this, and don’t have an answer, perhaps @matt.dalkie could chime in. There are clear benefits to reducing the water content and by extension the cement content required to achieve strength and durability. I suspect that the admixtures confer a larger benefit then their associated emissions, but would like to see the numbers.

hi @ForestBorch - I’ve heard Master X is an option, but comes at some cost premium. Would also be keen to crowd-source additional information. Thanks for asking the question!

@Luke-Lombardi, thanks for the resource. Cost is an issue, but if the building can be constructed more quickly it may be worth it. Those gains in construction time would be difficult to give up for a mix with less cement and therefore lower GWP.