Issue link: https://mastery.commandalkon.com/i/1127584
ARIZONA METRO MIX CASE STUDY The Result The company delivered 200 loads up to the mountain to the job site, and had estimated 10 loads of concrete to be rejected because of air issues. The total number of rejected loads? Zero. Companies spend millions of dollars on equipment to produce concrete while missing the systematic control of water and its effect. Arizona Metro Mix believes that tools are available to help. Since their "mountain" project, Arizona Metro Mix continues to leverage the Precision Water System to the benefit of their customers providing improved service, customer satisfaction and retention through consistency. Bob Matthews, Operations Manager at Arizona Metro Mix, is a former contractor who relies on his experience along with great products from Command Alkon to achieve results. This experience reinforced his belief that if the water is controlled then results will be predictable. The proper amount of water stabilizes the strength, the bleed water, finishing effort, and set time characteristics of the concrete. Consistent water also means control of the entrapped air. Bob likes to say that air "travels" in the paste (water, cement, some sand). A consistent amount of paste, with a consistent amount of air entrainment agent, will yield consistent results. For a specific example, if sand is running at 5% moisture, 1800 lbs. (818 kg) of sand contains 90 lbs. (40 L) of water. That's over 10 US gallons. If not compensated for this is extra water which must go somewhere… either to the bottom of the slab, create excessive bleeding off, or break out of the (finished) concrete later which leads to cracks and/or reduced wear- ability. If there is too much sand, the finished concrete can be too dense, smothering the hydration process, preventing the bleed water from properly evaporating. Rock is less of a problem but enough rock is needed to create voids so the water can escape. Remember: 20 to 50 pounds (9 to 23 kg) per yd3 (.76 m3) of sand that is not moisture adjusted can have a substantial effect on the curing behavior. Arizona Metro Mix also provides a substantial amount of colored concrete. Many will agree that colored concrete can be problematic. Bob has discovered that problems with color in his market are primarily due to sand and water. To be successful first keep the sand color consistent. Just as importantly, closely monitor the water. Colored concrete is a bit like paint, if you vary the water in a can of paint the color will vary - the same applies for colored concrete. Arizona Metro Mix has used the Precision Water System to deliver 2500 yd3 (1923 m3) for colored panels and has not had a single panel rejected. Maricopa County, where Arizona Metro Mix is located, specify recipe (prescription) mixes. On those mixes, the standard deviation for breaks has dropped 36% to 346 lb. (2.38 MPa) since the addition of Precision Water System. On the (non-recipe) production mixes Arizona Metro Mix has used this consistency to drop about a half a sack of cement per load equating to annual savings of $40,000. Before Arizona Metro Mix, Bob worked at a company that delivered a job requiring 10,000 PSI (68.9 MPa) concrete in seven days from a COMMANDbatch equipped with Precision Water System. The requirement was for 24" (60 cm) to 30" (76 cm) spread. Every load was tested, and Bob never lost a load due to water variation. During one stretch he hit the 26" (66 cm) spread target on 22 straight loads. Improved productivity is another benefit. If the concrete is right, the drivers don't need to wait or spend time at the slump stand. Getting them out in 5 min vs 7 can save 2-3 trucks on a 300 yd3 (230 m3) pour. Transforming your operations by replacing manual and complex tasks and processes with efficient, scalable, and reliable solutions. Learn more at commandalkon.com Copyright © Command Alkon Incorporated. All rights reserved.