Concrete creates a tremendous amount of heat as it cures. Large concrete structures require a cooling method so as to maintain structural integrity. Some of the largest structures in the world are dams. These structures tame floods, act as a reservoir for irrigation, and hydraulically generate clean electrical power.
Hoover Dam Facts
The pioneering structure in the United States is the Hoover Dam, perched on the Colorado River between Arizona and Nevada. Standing over 726 feet high, 1,244 feet wide, 660 feet thick at the base and narrowing to 45 feet at the top, Hoover Dam at completion was the largest dam in the world. Over 4.4 million cubic yards went into building this colossal structure. Four million cubic yards of concrete is a lot. The concrete was poured in cubit sections some 25 by 25 foot wide, 5 feet thick blocks in the back side and up to 60 x 60 feet long facing upstream. That is equivalent to 86% of the concrete used by the Bureau of Reclamation over the previous 27 years. Needless to say a lot of heat was generated.
How Was the Hoover Dam Built; Concrete Cooling System
Water is a very good medium for heat transfer. That is why it is used in automobile radiators, and in the 1930s the Colorado had a lot of water. Pipes where embedded into the concrete and water was pumped through the structure to carry away the heat. Over 582 miles of cooling pipes was laced throughout the structure. After the initial “set” of the concrete, the water source was switched to a chilling plant. The cooler water provided a faster cure rate. Even the concrete was cooled before pouring. The water was cooled by using ice water. An ice plant producing an astounding 1,000 tons of ice a day was built, and in two months the concrete was cooled block by block. The typical “dump” from the cable suspended concrete buckets added at most a six inch layer spread throughout the concrete box forms. So “Virginia” contrary to rumor, no bodies are encased in Hoover Dam. Over 100 persons died in the construction of Hoover Dam, but none were buried in that structure.
Hoover Dam Heat Pump
Industrial water chillers like heat pumps circulate a fluid, in this case water not Freon for cooling. Air is forced through a radiator type structure, the condenser, which exchanges heat from the water to the air, cooling the water in the condenser. The water is then pumped to the evaporator, another structure resembling an automobile radiator. Air forced through the coils is cooled by the water, and the heated water circulates back to the condenser. Of course this is very simplified, there are pumps and compressors, electrical switching valves and circuits to control the process. But simple as it is, the evaporative or fluid heating stage, followed by the condensing and cooling phase is the basis for nearly all cooling and many heating systems. Reverse the order, and you have heating instead of cooling, in other words a heat pump.
Is Hoover Dam Concrete Still Curing?
In short, yes – the concrete is still curing, harder and harder every year even in 2017 some 82 years after the construction of Hoover Dam was completed in 1935.