Dispersants For ULCC Composition

[silbord]

I am looking for suggestions on effective dispersants for an ultra low cement composition that uses fused quartz + micro silica + CAC or Portland cement binder( approx. 2-3% cement).

I tried Melflux 2651(polycarboxylate), Additive A (modified calcium lignosulfonate), Darvan 7S (sodium polymethacylate), Darvan 811D , sodium hexametalphosphate but was not able to reduce the mixing water to 5-6%. I had to use 10-15% watter in order to get good slump. Because of excessive amount of water used, the cast sample would not set quick enough. It would take two to three days for the sample to set.

Thank you

 

[concretemasonry]

Is this for factory cast or for site cast concrete?

Since you are aiming at 5-6% "mixing water", you have a challenge. If the "aggregate" is dry, aggregate absorption/surface absorption(based on fineness) can suck moisture out of the cement matrix and leave little for cement hydration.

Since you are measuring the workability/plscement by a "slump", I assume you are trying to use wet cast parameters to near-zero slump concrete, which behave differently.

If you have the luxury of factory vibration and curing there are many practices that can be adapted. - Look toward the concrete block, concrete pipe and some flat precast manufacturing techniques for material handling/sequencing. If you are limited to a site situation, the sophistication and controls of these processes may not be applicable to your needs. Curing also provides an opportinity to introduce moisture after molding/placement.

More information on the process/application would help with constructive assistance.

Dick