00131696

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http://onlinepubs.trb.org...s/trr/1975/558/558-010.pdf

https://scholar.google.co...rjee&publication_year=1975

Strength of field-cured concrete has been estimated by correlating the maturity of strength, the maturity being a function of age and curing temperature. Additional standard cylinders are cast, and the maturity of inplace concrete is determined from thermocouples cast into the concrete pour or maturity meters installed during placing of the concrete. Standard cylinder strength and field maturity are then correlated, and in-place strength is determined by using constants for the concrete used. To check the validity of this approach, a series of strength tests on 4-in. (10-cm) cubes at various maturities were conducted in the laboratory. These sets of cubes were cast from concrete obtained from various job sites in Toronto. Seven and 28-day cylinder strengths predicted from low-maturity cylinder strengths of the same set were evaluated. The constants of the strength-maturity equation were determined to suite the local normal concrete and to compare the results with those of Plowman. A satisfactory correlation was obtained. The method was used to predict the in situ strength of concrete slabs during construction of buildings at the University of Waterloo in 1971 and 1972. The contractor could then strip the forms early and determine if there were any inadequate curing conditions during winter construction. Tests were made during construction to check the actual strengths of the in situ concrete and to compare them with predicted theoretical values. The results were satisfactory. The gain of lightweight concrete floor slabs of a 37-storied tower recently completed in Toronto was monitored to determine the earliest time when posttensioning operation of the slabs could be carried out safely.

Publication of this paper sponsored by Committee on Mechanical Properties of Concrete.Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01411416

pp 87-92

1975

Transportation Research Record

54th Annual Meeting of the Transportation Research Board

0309024668

Print

Figures (8) ; References (5)

Age; Cold weather construction; Concrete; Concrete curing; Concrete tests; Correlation analysis; Equations; Field tests; Forecasting; Laboratory tests; Specimens; Strength of materials; Temperature; Thermocouples

Maturity

Data and Information Technology; Highways; Materials

TRIS, TRB

Jun 5 1976 12:00AM

• ACCELERATED METHODS OF ESTIMATING THE STRENGTH OF CONCRETE
• ACCELERATED SPLITTING-TENSION TEST FOR DETERMINING POTENTIAL 28-DAY SPLITTING TENSILE STRENGTH AND MODULUS OF RUPTURE OF CONCRETE
• ACCELERATED TESTING FOR PREDICTION OF 28-DAY STRENGTH OF CONCRETE
• CANADIAN EXPERIENCE IN THE USE OF THE MODIFIED BOILING METHOD
• DEVELOPMENTS IN THE PREDICTION OF POTENTIAL STRENGTH OF CONCRETE FROM RESULTS OF EARLY TESTS
• EARLY STRENGTH TEST FOR QUALITY CONTROL OF CONCRETE
• EVALUATION OF A CHEMICAL TECHNIQUE TO DETERMINE WATER AND CEMENT CONTENT OF FRESH CONCRETE
• FIELD EVALUATION OF EXPANDED POLYSTYRENE MOLDS FOR SELF-CURED, ACCELERATED STRENGTH TESTING OF CONCRETE
• PERMEABILITY TESTING OF PLASTIC CONCRETE
• PRACTICAL APPLICATION OF THE MATURITY CONCEPT TO DETERMINE IN SITU STRENGTH OF CONCRETE
• PREDICTION OF STRENGTH DEVELOPMENT IN CONCRETE STRUCTURES
• STRENGTH TESTS AT EARLY AGES AND AT HIGH SETTING TEMPERATURES