Concrete Mix Design Reducing Water Absorbtion

Have you considered waterproofing the concrete after it is placed and before the absorption test? All concretes are porous and will absorb water unless you render it hydrophobic. www.StableCrete.com/projects will give you an idea of how different concrete structures are waterproofed after placement.

Waterproofing also creates a No-Low Moisture/ Oxygen environment to prevent corrosion of embedded steel reinforcing members. May be easier than a new mix design?

I'm assuming that your concrete mixture is intended for a water retaining structure perhaps? Then if so, you may want to look into the concrete admixture product called "Xypex". There are several similar products by other chemical manufacturers out there in the market. Also, check/search the CR4 forum blogs as I believe that this very question was discussed sometime in the Winter or Spring of 2010.

Hi,

Reducing concrete water absorption is mainly about making the concrete matrix denser and reducing connected capillary pores. Before redesigning the mix, it is worth reviewing several key parameters:

• Lower the water-to-cement (w/c) ratio while maintaining workability with a high-range water reducer (superplasticizer).
• Optimize the aggregate grading to reduce voids.
• Ensure proper compaction and curing, as inadequate consolidation or curing can significantly increase water absorption.
• Consider supplementary cementitious materials such as silica fume, fly ash, or slag, which can refine the pore structure and improve long-term durability.
• Verify that the air content is within the target range, since excessive entrained air may contribute to higher absorption.

In many cases, reducing the w/c ratio with a polycarboxylate ether (PCE) superplasticizer is one of the most effective ways to lower water absorption without sacrificing workability.

If you're interested, we have published a number of technical resources on concrete admixtures, PCE superplasticizers, and mix design optimization here:

Huaxuan High-Tech

If you can share your current mix design (cement content, w/c ratio, aggregate grading, admixtures, curing method, and test standard), I'd be happy to discuss possible improvements in more detail.

Best regards,