Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
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Book Description
Since 1993, the Quebec Department of Transportation requires all its concrete suppliers to demonstrate that their concrete satisfies the requirements of the CSA A23.1 standard as regards the maximum spacing factor of the air void system. This new requirement raises questions about the reproducibility of the ASTM C 457 test method. An interlaboratory study was carried out to verify if the variability of the test method is sufficiently low to allow reliable decisions on the acceptance or rejection of in-place hardened concrete. A total of 18 operators from 13 different laboratories microscopically examined the six concrete slabs used for the study. It is concluded that the average reproducibility coefficient of variation is 14.4 % for the total air content measurement and 14.2 % for the spacing factor measurement. Considering these results, the probability that the measured value of the spacing factor exceeds the mandatory limit of 230 um on a concrete production containing an air void system with a spacing factor of 170 um (the target value proposed in the CSA A23.1 M-94 standard is less than 0.7 % (a propability of error of about 1 %, 5 %, or 10 % is typical of most quality control test methods).
Author: R. Pleau
Publisher:
ISBN:
Category : Air voids
Languages : en
Pages : 9
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Book Description
Many parameters affecting the quality of the air void characteristics measurement are reviewed and discussed. The difficulties more frequently encountered during the measurement process are described, and some simple rules are proposed in order to increase, as much as possible, the accuracy and reproducibility of the test. The influence of the sampling size is studied, and the variability of air content, specific surface, and spacing factor is estimated from a statistical analysis of about 600 different concrete mixtures. The influence of the operator's subjectivity is also investigated, and the effect produced by large air voids on the computation of the spacing factor is discussed.
Author: Paul Klieger
Publisher: ASTM International
ISBN: 0803120532
Category : Concrete
Languages : en
Pages : 621
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Author: Joseph F. Lamond
Publisher: ASTM International
ISBN: 0803133677
Category : Technology & Engineering
Languages : en
Pages : 661
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Author: M. Pigeon
Publisher: CRC Press
ISBN: 1482271443
Category : Technology & Engineering
Languages : en
Pages : 259
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Book Description
This book provides a comprehensive and authoritative review of durability of the frost resistance of concrete. It will enable both concrete materials specialists and practising engineers to better understand the deterioration processes which take place during freezing and thawing, and the effects of de-icing salts on concrete. It shows how test pro
Author: Basil Mark Harris
Publisher:
ISBN:
Category :
Languages : en
Pages : 634
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Author: M. Fickelson
Publisher: CRC Press
ISBN: 0203626729
Category : Architecture
Languages : en
Pages : 339
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Book Description
Testing of materials and manufactured items is a key element in the process from standard specifications though control and verification during manufacture to trade in actual products. Cooperative agreements and networks are being set up covering reference materials and calibration. This process is becoming more urgent with the development in the European market and other international developments. This book presents international views on this fast changing field, with the main themes of: technical components of test quality; quality assurance in testing laboratories; laboratory accreditation and transnational recognition of test results.
Author:
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 102
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Book Description
Since air-void analyzer (AVA) was introduced in the 1990s, various studies have been conducted in the United States to apply this technology. Many concerns are raised on (a) the variation of the AVA tests, (b) the relationship between AVA and other standard measurements, and (c) AVA specification limits. The application of AVA tests in concrete practice is therefore very challenging. The goals of the present research project are to reduce variability and improve precision of AVA test results and to develop rational specification limits for controlling concrete freezing and thawing (F-T) damage using the AVA test parameters. The project consists of three phases: Phase 1 -- Literature search and analysis of existing AVA data (June 2007-August 2008), Phase 2 -- AVA testing procedures and specification modification and Phase 3 -- Field study of AVA and specification refinement. In the present research report, the major activities and findings of the Phase 1 study are presented, and the major tasks for the Phase 2 study are recommended. The major activities of the Phase 1 study included the following: performing a literature search, collecting and reviewing available AVA data, completing a statistical analysis on collected AVA data, and carrying out some AVA trial tests in lab. The results indicate that AVA is a time- and cost-effective tool for concrete quality control. However, robustness of the AVA equipment, test procedures, and resulting interoperations need further improvement for a proper implementation of the AVA technology in concrete practice.
Author: Lawrence J. Kaetzel
Publisher:
ISBN:
Category : Expert systems (Computer science)
Languages : en
Pages : 274
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Book Description
Author: C. H. Best
Publisher: ASTM International
ISBN: 9780803106123
Category : Technology & Engineering
Languages : en
Pages : 886
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