“A total of 3,250,000 cubic yards (2,480,000 m3) of concrete was used in the Hoover dam before concrete pouring ceased on May 29, 1935. In addition, 1,110,000 cubic yards (850,000 m3) were used in the power plant and other works. More than 582 miles (937 km) of cooling pipes were placed within the concrete. Overall, there is enough concrete in the dam to pave a two-lane highway from San Francisco to New York. Concrete cores were removed from the dam for testing in 1995; they showed that “Hoover Dam’s concrete has continued to slowly gain strength” and the dam is composed of a “durable concrete having a compressive strength exceeding the range typically found in normal mass concrete.”
