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Would You Drink it?

The rule of thumb when you’re looking at an aggregate for use in your mix designs is to pay attention not only to its dispersion across the screens, but more importantly the percentage of material retained on the pan. The retention on the pan passing the #100 sieve being usually around 6 percent or less. The reason for this is that the particle size passing the 100 screen is small enough that it can actually inhibit the crystalline growth that is a byproduct of cement hydration. The finer the mix, the more cement is needed to cover the aggregate particles. Another potential culprit for adding excessive fines, is your mix water. Ideally, your mix water should be potable as a result of it being either city water or has gone through a filter and softening process. Pulling water directly from a well could be as detrimental as having high fines content in your aggregates. If you’d like to do an in-house check, take a small amount of your mixer water and place it in a clear glass cup. Place a coffee filter over the top of the glass and let the water evaporate. When totally evaporated see what’s left, if it’s clear that’s great.  If it’s hazy or you can see deposits, you may want to address your filtration methods. For more information contact Production Specialist Mike Maroney.

Color Matching

Eventually, one of your architectural salespeople is going to bring in a sample of concrete from another producer and ask if your operation can produce it. Don’t worry, because you may not be able to get an exact match, but you can certainly take a stab at it without tying up profitable machine time. Percentage out your closest matching architectural mix design to a 500-gram representative batch and adjust your pigment loading as needed. If you’ve got a vibrating table and a form, you should be able to simulate your consolidation. Put the samples on a blank pallet in your curing chamber and when the cycle’s complete, see how close you got to the salesperson’s sample. There are some nuances that need to be addressed when sample matching, so if you need help contact NCMA Production Specialist Mike Maroney.

Do you have a production question? ASK MIKE!

Material flow and the feed drawer

If you start seeing a gradual decrease in the amount of material filling the mold box, don’t immediately increase your feed time. Stop the block machine in accordance with your safety policy and take a look at your feed drawer for buildup. When wet concrete builds up in the box due to hydration, your material flow can become restricted or clogged. For more information, contact Production Specialist Mike Maroney.

Knowing why

Go out on the floor and ask your production personnel what ASTM International C90-14 is or ASTM International C1372-11. Depending on the size of your operation and the number of products that you produce, it can be assumed that you’re not going to have 100 percent recognition of these standards by your employees. Set up a meeting, incorporate a discussion on ASTM International Standards into your toolbox talks, do anything and everything to get your staff up to speed with the minimum requirements of products that they produce on a daily basis. For more information or help incorporating this into your toolbox talks, contact Production Specialist Mike Maroney.