Mass Concrete Mixtures Optimized for Temperature Control and Workability

About the report:

Mass concrete is prone to thermal cracking, ultimate strength reduction, and deleterious chemical reactions due to a high temperature rise.  Defining mass concrete has been difficult since many factors affect the thermal behavior and the distress formation.  Mass concrete is usually reinforced and may have geometric constraints that require concretes with high workability, as with self-consolidating concrete.  For high workability and strength, typically high amounts of cementitious materials are used. Such high amounts generally require high water and paste contents that lead to cracking because of moisture loss and thermal contraction. 

In this study, a practical and useful definition of mass concrete was developed.  Concretes with low cementitious material contents and high workability were investigated.  To minimize the total cementitious material and paste contents, optimum aggregate gradations were incorporated into the mix designs.  To achieve and maintain high workability during construction, a combination of admixtures was used that included high range water reducing, workability-retaining, and viscosity-modifying admixtures.   Laboratory testing of concretes with reduced cementitious material contents including high amounts of the supplementary cementitious materials and a combination of admixtures showed concretes with a decreased temperature rise, high workability, and adequate strength can be obtained.

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