Mixer loading procedures are critical to achieving optimal results in the production of HPC concrete.

If ambient temps are in the 80’s it is highly recommended to use Ice for at least 1/2 of water, to achieve optimal 60 minutes of full placement time for CSA mixes.

1. Load Aggs, and/or, 1/3 of sands into the mixer
2. Load Portland Cement into mixer
3. Load your mixer with your ice water and Liquid Z, use your lower w/c ratio….load it all don’t hold anything back. Let this tumble 1-3 Minutes…long enough to fully cool your mixer and melt some of the ice and create a cement slurry.
4. Add UltrasealZ to mixer slurry slowly to keep materials wetted out (let mix 2-3 min)
5. Add Super Sealz or Super flows to mixer
   (*Test to determine if additional SuperSealz or SuperFlows as needed per mix)
6. Add 1/2 of remaining sands, keeping mix wetted out
7. Add pigments if used
   (* if using any super colors, powder or liquid versions, hold 5-10% of water out upfront)
8. Load set accelerators (Qwix or other) and Fibers, add slowly to keep mix wetted out
9. Add remainder of sands to mixer, continue to mix until fully dispersed, 10-12 min. There is no need to load the materials too fast…just slowly add to keep the mix wetted out.
10. Temper Mix as needed with additional Super and/or liquids that were held back up front

Once all the sand have been added, let the total mix for 10-15 minutes before thinking about any trim water.   Add trim water if needed to maintain a fluid mix (it should turn into a full roll mix with the blades easily cutting through the mix)…..be careful with the water it will surprise you how flowable this mix will get.  If any trim water is added, allow a minimum of 2-3 minutes for full dispersion.

The steps of mixer loading, or bucket, are very important. Without proper loading procedure there is a wealth of issues that can potentially happen.

1. Loading too many dry ingredients up front sacrifices hydration of cements and cements paste…..leading to lower strengths and higher porosity

2. Loading too many dry ingredients up front sacrifices total electrolytes ability and charge, too much surface area up front.

3. Loading pigments up front early with cements increases total air, air that a defoamer will not combat effectively. Since the air is being caused by an incompatibility of the pigment wetting agent and the high alkaline cement slurry.

4. Loading the ingredients too quickly sacrifices total electrolyte dispersion. This can lead to hot and cold spots….higher and lower densities….in the final products. As well as potential dusting and leaching of the product.

5. Loading the plasticizers too early leads to incomplete dispersion, as the supers compete with the electrolytes for charge differences. This leads to a false sense of needing more super….leading to bleed potentials as the supers would begin working too late in the mix cycle or in the mold.