Is the addition of 5% to 15% Limestone interground with quality clinker detremintal to strength?
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K G
Limestone has better grindability in comparison to clinker; hence will be ground finer during inter-grinding. It does not react with alkalies released during cement hydration. However it acts as a inert filler during concrete hardening, resulting in refinement of pore structure and corresponding increase in strength. The percentage addition should be decided by conducting trials. http://www.drjdbapat.com
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Dr J D Bapat
Forgot to mention that when we changed precast vibrated C 45 strength using 360 kg CEM I 52.5 R cement to precast SCC 180 kg CEM 52.5 and added 180 kg GGBS and 180 kg GCC we reached easily C 65! In general, GCC will add to early and 28 day strength though at high amounts you might see a drop of 10% after one year.
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Boudewijn Piscaer
Thank you Boudewijn and Dr Bapat,
Another question on the subject: Does the addition of ground Calcium Carbonate to cements make concretes produced with such binders more suseptable to Thaumasite attack (in the absence of limestone aggregates), and if so at what level of addition would this become critical?
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K G
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