Construction is considered one of the least efficient industries in the U.S. Underutilized labor, idle jobsite equipment, and product waste plague efforts for improvement. The concrete industry, especially ready-mx producers, also face this challenge. Products comprised of portland cement account for more than half of all demolition waste; in 2013, the figure approached 270 million tons, EPA says.

In 2013, In “The Role of Waste and Performance Management in the Construction Industry,” published in the Journal of Environmental Science and Technology, John Rudolph Raj and A. Seetharaman found that “Waste management is very important for a companies’ profitability. This is because if a company can manage its waste properly, reduction in waste can help the company to reduce its cost.

The year 2016 marked a culmination of more than 20 years of research and discussion, as the concrete industry has finally adopted new approaches to waste management, through revised specifications and procedures that can reduce process waste. Eric Koehler of Titan America has worked through ACI and ASTM committee to help foster these changes to product specification. As a result, these committees are beginning to influence the way producers can eliminate process material waste and increase margins.

Three product-related process improvement initiatives have been approved over the past few years:

  1. In ASTM C94, Standard Specification for Ready-Mixed Concrete, a new provision in 2013 allows the automatic addition of water to control slump during transit. One system that accomplishes this is Verifi.
  2. There are two standards that apply to the use of limestone fines in concrete and portland cement, one for concrete containing ground limestone or aggregate mineral fillers; the other for limestone interground with Portland cement: ACI 211.7R, Guide for Proportioning Concrete Mixtures with Ground Limestone and Other Mineral Fillers was published in 2015; ASTM C1797, Standard Specification for Ground Calcium Carbonate and Aggregate Mineral Fillers for use in Hydraulic Cement Concrete was published in 2016.
  3. ASTM C1798, Standard Specification for Returned Fresh Concrete for Use in a New Batch of Ready-Mixed Concrete, published in 2016, allows producers to sell concrete that includes returned concrete as a mix component.

Producers might think these objectives are different from one other, but they are not. First, by allowing documented, automated slump adjustments during transit, producers not only mitigate load rejection, they better-control ingredient usage.

Using mineral fillers enables aggregate producers to reduce the landfilling of mining fines; and using ground limestone as filler or interground in the cement helps reduce clinker intensity per cubic yard of concrete. And with the new specification on returned fresh concrete, producers can establish procedures to reuse fresh concrete that is returned from the jobsite, assuring customers that it will meet required performance specifications.

Koehler joined many of these task groups and committees at a critical time. He and his fellow committee members adopted a different approach to reducing production waste. Their focus was more on how to improve operating procedures than avoiding landfills. “Production managers are more willing to adopt initiatives when they see the full range of operating benefits,” says Koehler. “We never looked at this as reducing quality by using more waste. Instead, it’s about using our resources more intelligently to move our industry to both zero waste and zero defects. Prior standards needed to allow a certain range of proven materials. What we have been able to do, through standardization, is show we can make this range a bit wider while make all stakeholders equal or better off than before.”

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