optimum range of plasticizer (SUPAFLO) in Self compacting concrete for M40 grade of concrete
an NSF based SP in a M40 acc is approximately 1.2-1.3% by cement + pozzolanic addition mass
Hi Mahi, Be careful with Naphthalene based admixtures, The normally en train air in high dosages and can cause serious retardation on setting and strength gain. For M40 concrete I would certainly not go beyond 1% of the cement content. Typical ranges are normally from 0.5% to 1.5%
not necessarily dosage of NSF higher than 1% promotes retardation in setting and hardening. It depends upon the substances in NSF based polymer present in super plasticizer. If the NSF is a pure polymer with negligible fraction having low molecular weight no retardation occurs. Moreover in sp presence of a defoaming agent impedes formation of entrapped air.
Coppola, I am not going to get involved in arguments about what admixtures does and does not do. I just warn the person because I talk from experience with Naphthalene's in specific. And on the matter of air en-training it is a warning in the brochures normally when using high dosages, again I am only warning because I again talk from experience.
Mahi There are better "New Generation" admixtures that might do a better job, but they come at a price. For "Low" strengths like 40 Mpa the older admixtures normally work out a lot cheaper but when you start going into higher strengths with SCC and you have to use Silica fume then you will have to use the newer Supers, retarders and most of the time Viscosity modifiers as well. Well good luck with your work and your exploration of concrete
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