Craig Yeack profiles NITROcrete, a Colorado-based company that has developed a process that involves spraying coarse aggregate with liquid nitrogen before batching. Matthew Nazarenko from NITROcrete says the cooling process is in use at more than 100 concrete facilities across the world.
What is control worth? In 1973, the visionary Bob Hawkins of Spence Concrete in McAllen, Texas jumped in with both feet. He was one of the first to purchase the 1150, the first all solid-state commercial concrete full batch controller from Alkon. This innovation replaced levers and wheels, and a guy who had forearms like Popeye the Sailor. The leap of faith was that tighter controls on batching would reduce costs and improve pricing power.
Hawkins’ gamble paid off for Spence and the entire industry, although it was not without growing pains. The “computer” was instructed by plastic cards, each representing a batch in 80 characters. The batchman would load a stack of cards in order, and each press of a button would produce a batch. Four decades later, technology innovator NITROcrete presents us with another debate about the value of control: Is there a better way to cool concrete?
The Art and Scient of Cooling
Hydration of portland cement is exothermic and throws off a lot of heat in two specific waves. In a hot ambient environment, think Death Valley, the added heat of hydration can quickly ruin the mechanical properties of the mix. Historically, chilled water for small temperature reduction or ice for more correction has been used to cool the constituents and save the day.
The problem with ice is control and safety. Typically, a driver—currently in critically short supply for our industry—has to climb up and down the rear ladder and add bags of ice. This increases the chances for injury. In terms of control, was that bag really 40 lbs., and did the driver really put in the right amount? Mistakes can quickly ruin the holy grail of quality control: the water-cement ratio.