https://www.usbr.gov/lc/hooverdam/faqs/damfaqs.html
a better link
How was chemical heat caused by setting concrete in the dam dissipated?
By embedding more than 582 miles of 1-inch steel pipe in the concrete and circulating ice water through it from a refrigeration plant could produce 1,000 tons of ice in 24 hours. Cooling was completed in March 1935.