For architectural concrete, congested reinforcement, and complex formwork, self-consolidating concrete (SCC) is often the best material to use to produce quality structures and surfaces, was the consensus of a sold-out session at last week’s World of Concrete. “SCC is necessary on many of the increasingly ambitious architectural projects we see,” said Megan Lenz, senior design engineer with Leslie E. Robertson Associates in New York. Euclid Chemical’s Bill Phelan, who organized and led SCC Today, noted that SCC lowers labor expenses and increases safety by requiring fewer workers and eliminating vibrators, which can cause white finger syndrome.
SCC Today had a battery of speakers representing all aspects of a project. Here are five things I learned during this session:
- One should never vibrate self-consolidating concrete since that could lead to segregation. However, at a lift line after a delay in concrete delivery, use a pencil vibrator to loosen up the surface of the existing layer. Kamal Khayat, Missouri S&T University
- For projects using self-consolidating concrete, hold preconstruction meetings and build mock-ups earlier since there is a high possibility that the architect won’t like the first one; and don’t produce perfect mock-ups—make them representative of the structure. Bill Phelan, Euclid Chemical
- For a good SCC mix, use both well-graded cementitious material (including fly ash, silica fume, and metakaolin) and well-graded aggregate. Steve Zimmerman, Reginald D. Hough Associates
- At the preconstruction meeting, don’t just invite the superintendent, but also invite the field leadership (foremen). Tony Martin, J&A Concrete
- Always have some extra high-range water reducer and viscosity-modifying admixture onsite in case a truck gets delayed or to handle unexpected weather conditions. Raul Herrera, Jenna Concrete Corp.
Look for another SCC Today session at World of Concrete 2017.