TIME DEPENDENT DEFORMATIONS OF TWO LIGHTWEIGHT AGGREGATE CONCRETES
A RESEARCH PROJECT WAS CONDUCTED BY THE OREGON STATE HIGHWAY DEPARTMENT IN COOPERATION WITH THE U.S. BUREAU OF PUBLIC ROADS TO DETERMINE THE CREEP AND SHRINKAGE CHARACTERISTICS OF 2 EXPANDED SHALE AGGREGATE CONCRETES. FOR THE EARLIER PHASE OF THE PROJECT, MEASUREMENTS WERE MADE FOR ABOUT 8 YEARS ON SPECIMENS SUBJECTED TO A CONSTANT COMPRESSIVE STRESS. OTHER PRISMS WERE SUBJECTED TO A COMPRESSIVE STRESS WHICH WAS PERMITTED TO DIMINISH AS CREEP AND SHRINKAGE OF THE CONCRETE OCCURRED. DEFORMATIONS OF THE LATTER PRISMS WERE MEASURED OVER A 5-YEAR PERIOD. TO PROVIDE A BASIS FOR COMPARISON, THE RELAXING STRESS PHASE OF THE PROJECT INCLUDED IDENTICAL SPECIMENS CAST FROM NORMAL-WEIGHT , SAND AND GRAVEL AGGREGATE CONCRETE. THE MAGNITUDES OF CREEP, SHRINKAGE, AND LOSS OF PRESTRESS MEASURED ON THE LIGHTWEIGHT PRISMS ARE COMPARED WITH THE VALUES MEASURED ON THE NORMAL-WEIGHT PRISMS. THE VARIOUS MEASUREMENTS FOR BOTH THE CONSTANT STRESS AND THE RELAXING STRESS SPECIMENS ARE PRESENTED AND THE SIGNIFICANCE OF THE VALUES AS APPLIED TO DESIGN IS DISCUSSED. FOR THE SPECIMENS SUBJECTED TO A RELAXING PRESTRESS FORCE, THE LOSS OF PRESTRESS WAS 50 PERCENT GREATER IN THE LIGHTWEIGHT PRISMS THAN IN THE NORMAL -WEIGHT PRISMS. /AUTHOR/
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Supplemental Notes:
- Paper sponsored by Committee on Concrete Superstructures and presented at the 45th Annual Meeting. 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.
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Authors:
- Beecroft, Gordon W
- Publication Date: 1966
Media Info
- Media Type: Digital/other
- Features: Figures; References; Tables;
- Pagination: pp 157-172
- Monograph Title: Bridges and structures
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Serial:
- Highway Research Record
- Issue Number: 147
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Compression tests; Creep; Deformation; Expanded shale aggregates; Lightweight aggregates; Lightweight concrete; Measurement; Prestressing; Shrinkage; Stresses; Time
- Geographic Terms: Oregon
- Old TRIS Terms: Compressive strength tests
- Subject Areas: Bridges and other structures; Highways; Materials;
Filing Info
- Accession Number: 00208232
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Nov 21 1994 12:00AM