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1、 AS 1379 Supp 12008 AS 1379 Supplement 12008 Specification and supply of concrete Commentary (Supplement 1 to AS 13792007) AS 1379 Supp 12008 This Australian Standard Supplement was prepared by Committee BD-049, Manufacture of Concrete. It was approved on behalf of the Council of Standards Australia
2、 on 10 April 2008. This Supplement was published on 12 June 2008. The following are represented on Committee BD-049: Ash Development Association of Australia Association of Consulting Engineers, Australia AUSTROADS Australasian Slag Association Cement Concrete and Aggregate AustraliaCement Cement Co
3、ncrete and Aggregate AustraliaConcrete Concrete Institute of Australia National Precast Concrete Association Australia Standards Australia wishes to acknowledge the participation of the expert individuals that contributed to the development of this Standard through their representation on the Commit
4、tee. Keeping Standards up-to-date Keeping Standards up-to-date Australian Standards are living documents that reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be
5、issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments that may have been published since the Standard was published. Detailed information about Australian Standards, drafts, amendments and new pr
6、ojects can be found by visiting www.standards.org.auwww.standards.org.au Standards Australia welcomes suggestions for improvements, and encourages readers to notify us immediately of any apparent inaccuracies or ambiguities. Contact us via email at mailstandards.org.aumailstandards.org.au, or write
7、to Standards Australia, GPO Box 476, Sydney, NSW 2001. The Standard is downloaded from Standard Sharing AS 1379 Supp 12008 AS 1379 Supplement 12008 Specification and supply of concrete Commentary (Supplement 1 to AS 13792007) First published as AS 1379 Supp 11997. Second edition 2008. COPYRIGHT Sta
8、ndards Australia All rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Published by Standards Australia GPO Box 476, Sydney, NSW 2001, Australia ISBN 0
9、7337 8748 7 AS 1379 Supp 12008 2 PREFACE This Commentary (AS 1379Supplement 1) was prepared by Standards Australia Committee BD-049, Manufacture of Concrete, to supersede AS 1379 Supp 11997. Objective The objective of this Commentary is to (a) provide background reference material to the Standard; (
10、b) indicate the origin of particular requirements; (c) indicate departures from previous practice; and (d) explain the application of certain Clauses. The clause numbers and titles used in the Commentary are the same as those in AS 1379 except that they are prefixed by the letter C. To avoid possibl
11、e confusion between this Commentary and the Standard, clauses are cross-referenced within the text, while Commentary clauses are referred to as Paragraph C. in accordance with Standards Australia policy. The Standard is downloaded from Standard Sharing 3 AS 1379 Supp 12008 CONTENTS Page SECTION C1
12、SCOPE AND GENERAL C1.1 SCOPE 5 C1.2 REFERENCED DOCUMENTS 5 C1.3 DEFINITIONS 5 C1.4 NOTATION 6 C1.5 SPECIFICATION OF CONCRETE 6 C1.6 METHODS OF ORDERING. 10 C1.7 BASIS OF SUPPLY 13 SECTION C2 CONCRETE CONSTITUENTS C2.1 GENERAL 15 C2.2 CEMENT CONSTITUENTS. 15 C2.3 AGGREGATES. 15 C2.4 MIXING WATER . 15
13、 C2.5 CHEMICAL ADMIXTURES 15 C2.6 OTHER MATERIALS 16 C2.7 LIMITATIONS ON CHEMICAL CONTENT OF CONCRETE. 16 C2.8 ALKALI AGGREGATE REACTION. 17 SECTION C3 PLANT AND EQUIPMENT C3.1 GENERAL 18 C3.2 STORAGE CONTAINERS. 18 C3.3 WEIGHING EQUIPMENT . 18 C3.4 LIQUID DISPENSING EQUIPMENT 18 C3.5 MIXERS 19 SECT
14、ION C4 PRODUCTION AND DELIVERY C4.1 GENERAL 21 C4.2 BATCH PRODUCTION . 21 C4.3 CONTINUOUS PRODUCTION . 26 C4.4 DELIVERY. 27 SECTION C5 SAMPLING AND TESTING OF CONCRETE C5.1 GENERAL 28 C5.2 SLUMP 28 C5.3 STRENGTH 29 C5.4 AIR CONTENT. 30 C5.5 CHLORIDE AND SULFATE CONTENT 30 C5.6 DRYING SHRINKAGE 30 C5
15、.7 7 DAY STRENGTH OF NORMAL-CLASS CONCRETE . 31 C5.8 OTHER PARAMETERS. 31 SECTION C6 SAMPLING, TESTING AND ASSESSMENT FOR COMPLIANCE OF CONCRETE SPECIFIED BY COMPRESSIVE STRENGTH C6.1 GENERAL 34 C6.2 SAMPLING AND TESTING 34 C6.3 PRODUCTION ASSESSMENT 35 C6.4 RECORDING AND DISSEMINATION OF PRODUCTION
16、 ASSESSMENT INFORMATION . 38 AS 1379 Supp 12008 4 Page C6.5 PROJECT ASSESSMENT OF STRENGTH GRADE. 38 C6.6 ASSESSMENT BY ALTERNATIVE METHODS WITH AN ACCEPTED OPERATING CHARACTERISTIC 38 APPENDICES CA UNIFORMITY OF MIXING. 39 CB GUIDE TO THE SPECIFICATION OF SPECIAL-CLASS CONCRETE. 40 CC MEANS OF DEMO
17、NSTRATING COMPLIANCE WITH THIS STANDARD 44 The Standard is downloaded from Standard Sharing 5 AS 1379 Supp 12008 www.standards.org.au Standards Australia STANDARDS AUSTRALIA Australian Standard Specification and supply of concreteCommentary (Supplement 1 to AS 13792007) S E C T I O N C 1 S C O P E
18、A N D G E N E R A L C1.1 SCOPE The Standard was prepared for use in the specification and supply of all concrete, whether or not it is addressed in the scope and application of AS 3600. It is not intended to apply to mortars or grouts unless these contain coarse aggregates. Requirements for mortars
19、for masonry construction are specified in AS 3700 and the methods for sampling and testing mortars in AS 2701. Requirements for grouts to be used for the grouting of prestressing tendons in ducts are specified in AS 3600. The supply of concrete by the premix concrete industry has been expressly but
20、not solely contemplated in the preparation of the Standard. It is not intended that this Standard take precedence over existing Australian Standards for the manufacture of specific concrete products. The Standard is intended to complete the independence of AS 1379 from AS 3600. Due to the lack of sy
21、nchronization in publishing dates, for many years concrete as a material relied on both AS 1379 and AS 3600 to one degree or another. AS 1379 is now a stand-alone document for the specification and supply of concrete. C1.2 REFERENCED DOCUMENTS The Standards listed in the Clause are subject to revisi
22、on from time to time and the current edition should always be used. The currency of any Standard may be checked with Standards Australia. C1.3 DEFINITIONS No Commentary, except for the following clauses: C1.3.6 Cement The meaning of the term cement has been extended beyond its traditional meaning of
23、 portland cement to include supplementary cementitious materials. For the purpose of this Standard, cement can be portland or blended cements as defined in AS 3972. Blended cements include any combination of portland cement with fly-ash, amorphous silica and ground granulated iron blast furnace slag
24、. C1.3.15 Project assessment Section 6 requires suppliers to continuously monitor the strength of the concrete supplied by production assessment. Project assessment is an additional assessment that may be specified, and attracts an additional cost. Currently AS 3600 requires project assessment to be
25、 specified for all special-class concrete. Project assessment may also be specified for normal-class concrete. AS 1379 Supp 12008 6 Standards Australia www.standards.org.au The customer should not assume the supplier is aware of any liability to conduct project assessment. It is the responsibility o
26、f the customer to commission an appropriate testing body to carry out project assessment. The supplier may be an available choice for this purpose. The customer may commission the supplier to carry out the specified project testing, making appropriate arrangements for the recovery of the costs invol
27、ved. Project assessment is discussed further in Section C6. C1.3.21 Total free water The only water considered to be available for hydration of cementitious materials is the total free water, being added water and the surface moisture of the aggregates. In this context, water separately added in the
28、 batching process, as distinct from water introduced as moisture content in the aggregates, is referred to as added water. Added water includes water contained in admixtures and water added to adjust slump at any time prior to or during discharge. The other component of total free water, the surface
29、 moisture content of aggregates, is defined as the total moisture content less the absorbed moisture content. Absorbed moisture is that contained within capillary fissures in the aggregate particles. It is considered to remain within the aggregates and not to be available to enter into chemical comb
30、ination with the cementitious materials. When aggregates are in a condition where the only water they contain is that which can fully occupy the capillary fissures within the aggregate particles, they are said to be in a saturated surface dry condition. To bring aggregates to this condition, they ar
31、e slowly dried from a higher moisture content until the surface water has evaporated. The saturated surface dry moisture content can then be determined. Any moisture the aggregates contain in excess of the absorbed moisture is referred to as surface moisture. C1.3.22 Water-cement ratio (w/c) Water f
32、or this purpose is defined as the total free water discussed in Clause C1.3.21 and cement as discussed in Clause 1.3.6. C1.4 NOTATION (No Commentary) C1.5 SPECIFICATION OF CONCRETE C1.5.1 General Normal-class concrete is presented as the specification method likely to suit the majority of applicatio
33、ns. Its properties are limited, albeit in reasonably wide ranges, in respect of a number of key parameters such as strength grade, density, aggregate size, slump and chemical composition. The quality compliance provisions of Section 6 anticipate that the majority of specifications would call up norm
34、al-class concrete. The entire concept of production assessment is based on this assumption. In turn, the customers level of protection also improves. Special-class concrete provides the specifier with the opportunity to specify parameters or values, which are not permitted in normal-class concrete.
35、C1.5.2 Standard strength grades With the increasing use of concrete with strength grades above 50 MPa, AS 3600 and, therefore, AS 1379 have introduced additional standard grades of 65, 80 and 100 MPa. This ensures that in specifying such grades, a standard approach is adopted for both design and pro
36、duction. The Standard is downloaded from Standard Sharing 7 AS 1379 Supp 12008 www.standards.org.au Standards Australia If special-class concrete is specified, it is preferable if the use of non-standard strength grades be avoided. If the strength grade is one of the standard grades, test data can
37、sometimes be grouped with the data used for production assessment of normal-class concrete of the same strength grade even though concrete may be special-class. Strength grades above 50 MPa, whether standard or not, are treated as special-class. The majority of structural concrete lies in the range
38、of strength grades from 20 to 100 MPa. For such concrete, the committees responsible for AS 3600 and the Standard recommend the selection of one of the values 20, 25, 32, 40, 50, 65, 80 or 100 MPa. The advantages of standardizing strength grades lies in the consequent increase in the volume of stati
39、stical information available for each mix and in avoiding a variety of unnecessary mix designs. The use of standard strength grades, whenever possible, will result in more test results being available for statistical analysis and will generate more reliable statistical parameters with which to asses
40、s quality. This will enhance the effectiveness of suppliers production assessment procedures, the principal tool for maintenance of the quality of concrete production. A technical distinction is employed in the Clause with the use of the term design characteristic strength. Characteristic strength i
41、s defined in Clause 1.3.7 as that value of the material strength, as assessed by the standard test, which is exceeded by 95% of the material. The word design is prefixed to it in the Clause to make clear that in this context the value referred to is the value upon which the designer relies. It is no
42、t to be confused with the value calculated from the test results for a particular grade, which will be expected to exceed the design value. C1.5.3 Normal-class concrete C1.5.3.1 General The Clause deals with various attributes and constituents of normal class concrete. Any restrictions on the use of
43、 supplementary cementitious materials or chemical admixture, limitation of basic shrinkage strain after 56 days drying to less than 1000 106 or departure from the limits of other attributes in Clause 1.5.3, would change the classification to special-class as follows: (a) Mass per unit volume The ran
44、ge of from 2100 kg/m3 to 2800 kg/m3 was chosen to accommodate satisfactory dense aggregates commercially available. Lightweight concrete (2100 kg/m3) would necessarily be special-class concrete. (b) Chemical content Normal class concrete in accordance with Clause 2.6 will have a chloride ion content
45、 limit of 0.8 kg/m3. NOTE: For commentary to limits on chemical content, see Clause C2.6. (c) Basic shrinkage strain The maximum basic shrinkage strain, after 56 days drying, of 1000 106 is a value to which suppliers of normal-class concrete in any area of Australia are committed. The following are
46、relevant when considering the appropriateness of this limit: (i) Practicality In some areas, the locally available aggregates and cement for the production of concrete will result in concrete with a basic shrinkage strain approaching this value. A lower maximum value for normal-class concrete would,
47、 in such areas, preclude the use of economical and otherwise satisfactory materials for use in normal-class concrete. Many areas have materials that will ensure the basic shrinkage strain of concrete in those areas is considerably less than 1000 10-6. Designers should ascertain the shrinkage charact
48、eristics of commercially produced concrete in any area by inspecting the records of suppliers in that area. AS 1379 Supp 12008 8 Standards Australia www.standards.org.au It is preferable that such enquiries be made before the specification of lower shrinkage strain limit is contemplated. (ii) Consis
49、tency A median value of 850 106 is used in AS 3600 for the basic shrinkage strain as an alternative to values determined from tests on the concrete proposed to be used or similar local concrete. The maximum to 1000 106 specified in the Standard includes allowance for the range of values each side of the median and for the testing precision in the determination of shrinkage. For further discussion on basic shrinkage st