Development of Very Low Heat Mass Concrete Mixtures for the Modification of Theodore Roosevelt Dam

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Title: Development of Very Low Heat Mass Concrete Mixtures for the Modification of Theodore Roosevelt Dam

Author(s): W. F. Kepler and K. F. Von Fay

Publication: Special Publication

Volume: 140

Issue:

Appears on pages(s): 269-280

Keywords: adiabatic conditions; compressive strength; dams; mass concrete; heat of hydration; high-performance concretes; mass concrete; strength; mix proportioning; temperature; water-cementitious ratio; Materials Research

Date: 9/1/1993

Abstract:
Theodore Roosevelt Dam is a rubble-masonry dam, located on the Salt River, 76 miles northeast of Phoenix, AZ. The dam will be modified by adding a mass concrete gravity section to the downstream face of the dam. Over 350,000 yd 3 of mass concrete will be placed. A high-performance mass concrete mixture was developed that met conflicting low heat and strength development requirements. The mixture needed to meet thermal requirements of no more than 45 F total adiabatic temperature rise in 20 days, and less than 5 F adiabatic temperature rise after 20 days. In contract, the mixture needed to meet early-age compressive strength requirements of 1000 psi between 3 and 7 days and have sufficient paste to insure bond between the new concrete and the original masonry structure. The Bureau of Reclamation developed a concrete mixture with a 4-in. maximum-sized-aggregate (MSA), containing 270 lb of cementitious material per pubic yard that met design requirements. The cementitious material consisted of 80 percent cement and 20 percent fly ash. A low-heat, Type II cement was used, with a heat of hydration of 65 calories per gram at 7 days. The fly ash is an ASTM class F ash. The concrete has a water-to-cementitious materials ration of 0.53. The mixture is very workable, and reaches a compressive strength of 1100 lb/in.¦ in 7 days. It has a total adiabatic temperature rise of 43.4 F, with only 2 F temperature rise after 20 days.