An Investigation of Concrete Setting Time, R-265 (MLR-75-4), 1975

(1975) An Investigation of Concrete Setting Time, R-265 (MLR-75-4), 1975. Transportation, Department of

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Abstract

A water reducing and retarding type admixture in concrete is commonly used on continuous bridge deck pours in Iowa. The concrete placed in the negative moment areas must remain plastic until all the dead load deflection due to the new deck's weight occurs. If the concrete does not remain plastic until the total deflection has occurred, structural cracks will develop in these areas. Retarding type admixtures will delay the setting time of concrete and prevent structural cracks if added in the proper amounts. In Section 2412.02 of the Standard Specifications, 1972, Iowa State Highway Commission, it states, "The admixture shall be used in amounts recommended by the manufacturer for conditions which prevail on the project and as approved by the engineer." The conditions which prevail on the project depend on temperature, humidity, wind conditions, etc. Each of these factors will affect the setting rate of the plastic concrete. The purpose of this project is to provide data that will be useful to field personnel concerning the retardation of concrete setting times, and how the of sets will vary with different addition rates and curing temperatures holding all other atmospheric variables constant.

Item Type: Departmental Report
Keywords: Admixtures, Bridge decks, Concrete, Data collection, Setting (Concrete), Time, Water reducing agents
Subjects: Transportation
Transportation > Bridges and tunnels
Transportation > Roads and highways
Transportation > Research
Transportation > Research > Concrete
ID Code: 16904
Deposited By: Iowa DOT Library
Deposited On: 13 May 2014 12:13
Last Modified: 07 Jan 2015 12:46
URI: http://publications.iowa.gov/id/eprint/16904