RheoTEC Z-60: The Value for the Ready-Mixed Concrete Producer 

Until now, the industry has not had a true solution for slump loss. Therefore, it is largely accepted as inevitable and is dealt with in a variety of inefficient ways from a production and profitability perspective. Effective control of slump loss that results in consistency between concrete loads, and in plastic and hardened properties can improve operational efficiency and profitability.

What makes the current methods inefficient and costly?

Over time the industry has developed several methods for counteracting slump loss, all of which are limited in their effectiveness. Three of the more commonly used methods can significantly reduce a concrete producer’s operational efficiency. They are:

• Re-temper – Results in an increased water-cementitious materials(w/cm), lower strength and, consequently, an increased mixture overdesign requirement. Addition of water to air-entrained concrete changes the plastic air content and prolongs the time a truck is on site by up to 10 minutes per delivery.
• Re-dose with High-Range Water Reducer – Usually requires the producer to deploy quality control staff at the jobsite when their time could be better utilized elsewhere. Using additional admixture increases the cost per unit volume (cubic yard or cubic meter) of concrete produced. Similar to the addition of water, redosing with HRWR can change the plastic air content and prolong the time a truck is on site due to the re-dosing and re-testing process.
• Batch to a higher-than-required slump –This technique assumes that the concrete will lose a precise amount of slump during transit and so arrive on site within specification. This can be a risky assumption based on changing materials or environmental conditions. In some instances, batching to a higher slump will require the producer to batch less volume per delivery, thereby increasing cost.

How does workability retention improve operational efficiency and enhance profitability?

By maintaining concrete workability from batching to placement a producer can save significant time and money in the following areas:

• Mixture overdesign - lowering mixture costs by reducing overdesign and eliminating admixture dosing on site
• Truck turnaround time - improve truck time efficiency by eliminating re-tempering, re-dosing and re-testing time on site
• QC personnel time - eliminate QC personnel time at the jobsite for re-dosing HRWR and/or for monitoring slump and plastic air contents.
• Delivery logistics - the concrete producer can batch to the correct slump and deliver full rather than partial loads. (Workability retention also allows a producer to deliver concrete to further distances, thereby improving delivery logistics.)

Solutions

Supplying concrete mixtures that maintain their desired workability from batching to placement can improve operational efficiency. BASF offers admixture technology designed specifically to help the concrete producer maintain workability and control performance. Contact your local BASF representative for more information on the admixture technology and tools designed to enhance operational efficiency and improve profitability.