Fru-Con Construction Corp. of St. Louis was faced with some interesting challenges when the company undertook a project repairing the Aswan High Dam in Egypt. These challenges included producing 9000 psi concrete in desert conditions where daytime temperatures often reach 130oF or more, placing concrete 70 feet under water, keeping the concrete temperature below 72oF until placed, and using a local work force that has never produced high-strength concrete to do it all.
Initially, Fru-Con developed the mix in the laboratory, and then followed up by verifying the mix using site-produced concrete. Developing mixes on-site allowed Fru-Con to thoroughly check the batch equipment, evaluate several potential methods of cooling the concrete to meet project requirements, and check production and hauling times.
After considering several different methods of cooling, Fru-Con decided to use mix water chilled with ice to 34oF and cooling coarse aggregate by direct injection of liquid nitrogen into the stockpile. Truck drums were wrapped in burlap and soaked with water to help shield the mix from heat.