I would like to ask the following regarding the Structural Waterproof Concrete:
-What is the terminology for Waterproof Cpncrete (and where is stated)
-What are the most practical laboratory tests for waterproof concrete (among the numerous that exists)
-What are the values on these tests that prooves impermeability (and how these values are corelated with service-life of the construction).
Best regards
Spiros Licoudis
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spiros licoudis
Spiros! Waterproof Concrete is a misnomer. It is concrete with low permeability. The permeability (typically water)of concrete can be reduced by refining its pore structure, using mineral admixtures like PFA, BFS, SF, MK and so on. The permeability of concrete is specified in the performance standard. It will be better to refer the national standard on the subject. http://www.drjdbapat.com
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Dr J D Bapat
Spiros,
Dr Bapat correctly called the expression or term "waterproof" concrete a misnomer. He also correctly focused on "refining" the pore structure. This refining is key to void control and requires careful managing and restructuring of the degree of residual voids, this determines the degree of porosity. Reducing your concrete voids is the first step to better resist liquids from being able to migrate through the matrix, but this is still not "water proof" or water tight or MVT controlled concrete.
The use of SCM's of various types are helpful but limited in creating the degree of void reduction for water tight (pore filling) to the degree you are looking for.
The other ingredients, not always adequately considered are better 1)cement 2)mix water utilisation. These need addressing as these also create voids when producing concrete. How? the mix water, when this exits, during the bleeding and drying phase. These are the most problematic voids and range from Macro to micro and are interlinked allowing for ease of migration for moisture.
Water needs to be utilized better during the hydration (of cement) phase. Additionally the cement needs to be better hydrated so as to consume more water. Then there is the additional consumption of the by-product hydrate Ca(HO)2 calcium hydroxide to futher increase paste production. If you understand how to utilise these you will also utilise better any SCM incorporated in your mix design.
The end result is ultra tight moisture resistent concrete, yet still breathable on the micro level. Healthy concrete.
If you require further info please contact eiitech@shaw.ca
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John Macdonald
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