One of the major sources of inconsistency in concrete production is the ever-changing moisture content of the sand and aggregates. For ready mix concrete producers, high-quality materials and well-controlled moisture levels are critical to ensure consistent products.
Understand and Control Your Materials
Aggregate stored in a stockpile or bin typically stays in a wet condition, absorbing water (absorbed moisture) and having moisture coat the surface (free surface moisture). The total moisture content of an aggregate sample is the sum of the absorbed moisture and the free surface moisture, and these factors are very important to consider when batching concrete.
If the moisture content of wet aggregate is not compensated for, the slump may be too high and the water to cement ratio won’t conform to the mixture requirement. The aggregate moisture must always be measured and the amount of batch water adjusted accordingly.
Loads that are not produced at the desired slump can result in additional costs and potentially damaged reputations from angry customers. Companies spend millions of dollars on equipment to produce concrete but miss the underlying control of water and its effect on the material. The proper amount of water stabilizes the strength, the bleed water, finishing effort, and set time characteristics of the concrete. Significant savings in cement, color and admixtures, as well as reductions in the number of wasted batches are all common benefits of moisture measurement.
Achieve Consistent Results
The Precision Water System (PWS) is a combination of hardware and software that work together to ensure that the load characteristics (slump, workability, yield, etc.) are achieved with the batching process. Combined with the powerful material target calculation functionality of COMMANDbatch, the Precision Water System can produce better concrete with less variability, and possibly lower cost.
- Produce consistent concrete from multiple plants
- Regular use of system ensures probes calibrations stay up to date
- Allows up to 12 moisture probes on a variety of materials up to 1-1/2” coarse aggregates (multiple probes recommended)
- Keeps a history of moisture samples and bake-out pairs for each probe-bin-material combination
- Default calibrations for a range of materials allow for immediate use of the system until bake-outs and final calibration occurs
- Existing E-Z CAL manual stations can be updated for Precision Water System software
Measuring and compensating for moisture in the aggregates is a critical part of any quality control process. This powerful tool can control the amount of water in loads, reduce/eliminate rejected loads, save time in the yard that would be wasted by constantly adjusting loads, and minimize on-job time.
Arizona Metro Mix has seen first-hand the power of the PWS system on a job where they had to deliver 200 loads to a job site on a mountain! Want to learn more? Check out this case study.