THE IN SITU COMPRESSIVE STRENGTH OF CONCRETE
Problems associated with the determination of the compressive strength of concrete in actual, full-size structures are reviewed: standard test specimens are rarely representative of in situ concrete; strength within a structure itself varies; the causes of these variations are unclear; and methods of estimating in situ strength are not very accurate. The relationship between the strength of separately moulded specimens and of in situ concrete is examined. In situ strength is estimated using the ultrasonic pulse velocity (UPV) method and compared against drilled core strength. Full size columns are tested to determine the nature of in situ denisty, UPV and strength variations. The effects of heat of hydration, formwork surfaces, curing conditions, and compaction on in situ variations are studied. Compaction is considered to be the most critical factor because segregation of the concrete makes estimation of in situ strength by the UPV method unreliable. The strength-UPV relationship depends heavily on the aggregate concentration of concrete. The photonegative method was developed as a quick, simple, and relatively low-cost means of estimating in situ aggregate concentration. The UPV-AWC (aggregate weight concentration) method is demonstrated and shown to give better estimations of relative in situ strength than the UPV method that is currently used. (TRRL)
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Corporate Authors:
University of Auckland
Department of Civil Engineering, Private Bag
Auckland 1, New Zealand -
Authors:
- Chia, JHC
- Publication Date: 1983-1
Media Info
- Features: Figures; Photos; References; Tables;
- Pagination: 390 p.
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Serial:
- Issue Number: 311
Subject/Index Terms
- TRT Terms: Aggregates; Columns; Compaction; Compression; Compressive strength; Concrete; Concrete curing; Core samples; Errors; Field tests; Formwork; Heat; Heat of hydration; Hydration; Measurement; Methodology; Samples; Speed; Strength of materials; Ultrasonic tests; Ultrasonics; Weight
- Uncontrolled Terms: Concrete strength
- Old TRIS Terms: Insitu methods
- ITRD Terms: 4577: Aggregate; 3686: Compaction; 5532: Compression; 4755: Concrete; 5700: Core (boring); 4702: Curing (concrete); 6440: Error; 3639: Formwork; 6743: Heat; 7195: Hydration; 6226: In situ; 9102: Method; 6251: Sample (mater); 5408: Speed; 5544: Strength (mater); 6739: Ultrasonic; 5485: Weight
- Subject Areas: Geotechnology; Highways; Materials; Planning and Forecasting; I32: Concrete; I72: Traffic and Transport Planning;
Filing Info
- Accession Number: 00390489
- Record Type: Publication
- Source Agency: Transport Research Laboratory
- Report/Paper Numbers: Monograph
- Files: ITRD, TRIS, ATRI
- Created Date: Mar 29 1985 12:00AM