Optimization of Curing Regimes for Precast Prestressed Members with Early-Strength Concrete

Abstract

Early-strength-concrete (ESC) made of Type I cement with a high Blaine value of 500 m(2)/kg reaches approximately 60 % of its compressive strength in 1 day at ambient temperature. Based on the 210 compressive test results, a generalized rate-constant material model was presented to predict the development of compressive strengths of ESC at different equivalent ages (9, 12, 18, 24, 36, 100 and 168 h) and maximum temperatures (20, 30, 40, 50 and 60 A degrees C) for design compressive strengths of 30, 40 and 50 MPa. The developed material model was used to find optimum curing regimes for precast prestressed members with ESC. The results indicated that depending on design compressive strength, conservatively 25-40 % savings could be realized for a total curing duration of 18 h with the maximum temperature of 60 A degrees C, compared with those observed in a typical curing regime for concrete with Type I cement.