Dosing & Mixing Helix® Micro Rebar®
Based on current literature and experience, the following recommendations are offered in an effort to maximize desirable performance characteristics and prevent Helix® reinforcement from clumping (small cluster of Helix® reinforcement).
Ready Mix Plants (Dry) – TRUCK
- Add all Helix to the truck drum. Typically this is done by hand, dumping the entire contents of the box into the drum while it is at idle speed. If available, this is done from a slump check stand.
- Drive the truck into the plant.
- Once truck is in the position under the chute, increase the drum to full charging speed and add a minimum of 50% of the batch water to the truck (more than 50% is OK).
- Allow the Helix and the water to mix for no less than 45 seconds while delaying the addition of the remaining materials. NOTE: Once the water and Helix are in the drum and the drum is at charging speed, the drum shall NOT decrease until all batching is complete.
- Add aggregate, sand, cement and remaining water to truck and mix in normal manner (60 revolutions minimum).
Site Batching Into Mix Trucks
(Loaded Truck at Construction Site)
- Set the drum to charging speed.
- Sift Helix® through a 2’’x 2’’ (50mm x 50mm) Mesh or use Helix® Dosing Unit (contact Helix® to order). The dosing unit breaks up clumps and ensures Helix goes into the truck at a controlled rate (about 1 box per minute). When Helix® is added at this stage, it must enter the mixer clump free.
- When adding Helix®, it may collect on any residual concrete on the interior surfaces of the hopper. Push the Helix® into the drum avoiding clumps. Adding a slippery lining, such as PVC sheeting, to the hopper may help avoid these buildups.
- Mix at charging speed for 5 minutes (60 revolutions) after Helix® is added.
Pan Mixer/Drum Mixer
- Set the mixer to the proper speed.
- Add Helix® at a rate of 45-60 seconds per 45 lbs (20 kgs).
- Helix® should be added with the aggregates.
- Mix at max speed for 5 minutes after Helix® is added.