Blocking and Tackling
As I reflected on the many challenges that I have experienced on hot mix projects, a common theme arose. The solutions were typically related to relying on basic practices that serve as the foundation of a great paving project. I did not always look to those basic practices first—and that decision usually resulted in wasting time looking for a smoking gun that did not exist. It was so common to miss basic practices that during my time as an area engineer in the Childress District, we created a training for our engineers and inspectors called Hot Mix 101. We came to think of this as our blocking and tackling training. That term comes from spring training for a football team. Every good coach knows that you cannot go straight into teaching the team its most exotic plays. They must start with the basics to establish the foundation to build everything else. A team that is not capable of the basic skills will never be a championship team.
Our starting point to develop the Hot Mix 101 training was to ask our senior inspectors what they thought were the important basics for a good hot mix job. They developed a great list, and we developed an eight-hour training to cover these foundational topics and asked our senior inspectors to lead these discussions. One of the topics that always stuck with me was that the hot mix can only be as good as the individual components. The inspectors reinforced that many problems start in the material stockpiles.
I can think of several project examples where simple stockpile issues created problems during laydown operations. One example was related to several days of high winds in Collingsworth County. There was a freshly plowed, sandy field upwind of a hot mix plant. The continuous wind-driven sand polluted the Type D aggregate stockpiles to the extent that overall gradation of the mix changed and created stability problems on the road. The final solution involved rescreening the D-rock stockpiles to match the Job Mix Formula (JMF) gradations. I have recently heard of a similar problem last year in a Gulf Coast location after a hurricane.
Another mysterious stability problem on one of my projects was ultimately solved when we observed the loader operator scraping up the soil in front of the stockpile every time the bucket was filled. A simple change in loader technique solved an issue that had been blamed on several other factors, including the quality of the asphalt material.
The lessons I learned during our Hot Mix 101 training have stuck with me for my entire career. A key takeaway was the focus on those foundational basic practices. When we get the blocking and tackling right, we greatly increase the chances for a successful project. I would suggest that every team could benefit from a strong spring training with a focus on the basics.
Stay safe out there.