Send in the special teams

Terms like calorimetry, modulus of elasticity, sulphate testing, retarders and corrosion inhibitors might not be commonly used by most of us, but for the Rinker Materials’ Florida Materials Division technical team, they are every day words.

Thanks to terms like these, our technical team has earned a reputation in the engineering community as the “go to guys” for concrete projects with special needs.

“Projects with special needs are actually becoming more and more routine in the last few years,” says Doug Thomas, Central Region technical manager. “For example, it used to be common for high rise decks to reach high early strengths in 5-7 days, but nowadays specialty concrete mix designs allow us to achieve these same strengths in as little as 24-48 hours. Projects are constructed much faster.”

“We have assisted a number of designers in re-writing specs and educating the engineering community on what they can expect concrete to do and not do in Florida,” says South Region technical man- ager Albert Romanach. “Engineers come to us for advice and consulting sometimes even if we didn’t get the job.”

The technical team recently helped Florida Hospital in Orlando, with construction of their cooling tower. To ensure that the building’s shell remained watertight, one continuous pour was needed. Since the 35-foot [10 metre] high cast-in-place walls were congested with reinforced steel, vibrating the concrete into place was not an option. The team formulated that a continuous pour of a special selfconsolidating concrete (SCC) mix using silica fume and corrosion inhibitor was the best option. It was Rinker Materials’ first self-consolidating concrete application (SCC) - a newer technology.

As if that wasn’t enough, the concrete also needed to set as the continuous pour progressed. To avoid pressure blowouts, the team calculated that no more than an 11-foot (4 metres) all liquid head could exist at any given time. The right combination of retarder and high range water reducing admixtures was critical to give them the right set time between three and five hours. In the end, the team nailed it with a set time of three and a half hours.