Title
AS 1012.11-2000 Methods of testing concrete - Determination of the modulus of
rupture
Licensee
Licensed to E.S.SURESH on 04 Jun 2002
Conditions of use
This is a licensed electronic copy of a document where copyright is owned or managed by
Standards Australia International. Your licence is a single user licence and the document may not
be stored, transferred or otherwise distributed on a network. You may also make one paper copy
of this document if required.
Web Check-up
1
AS 1012.11—2000
TM
Australian Standard
AS 1012.11
Methods of testing concrete
Method 11: Determination of the modulus of
rupture
1 SCOPE
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
This Standard sets out a method for determining the modulus of rupture of concrete test
specimens prepared in accordance with AS 1012.8.2 tested as simple beams with third-point
loading.
NOTES:
1 This Standard may involve hazardous materials, operations and equipment. This Standard
does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this Standard to establish appropriate safety and health practices
and to determine the applicability of regulatory limitations before use.
Relevance of this Standard to fibre-reinforced concrete is to be further investigated.
Committee BD/42 is seeking information from all interested parties.
2 REFERENCED DOCUMENTS
The following documents are referred to in this Standard:
AS
1012
1012.1
1012.8.2
1012.9
2193
Methods of testing concrete
Method 1: Sampling of fresh concrete
Method 8.2: Method for making and curing concrete — Flexure test specimen
concrete specimens
Method 9: Determination of the compressive strength of concrete specimens
Methods for the calibration and grading of force-measuring systems of testing
machines
3 ACCEPTANCE OF TEST SPECIMENS
Moulded flexure test specimens shall be accepted for testing if they have been moulded in
accordance with the provisions of AS 1012.8.2, and if they are free from defects likely to
affect their strength.
Where specimens liable to rejection are tested, all apparent defects shall be noted in
accordance with Clauses 9 and 10 of this Standard.
Specimens shall be liable to rejection if any of the following conditions exist:
(a)
Chipped edges, surface cracking or honeycombing are apparent anywhere in the
tested span.
(b)
The surfaces of the specimen are out of plane such that any of the lines of contact
between the bearing surfaces on which the rollers bear are out of plane by more than
0.1 mm.
www.standards.com.au
© Standards Australia
AS 1012.11—2000
2
4 APPARATUS
4.1 Testing machines
The testing machine shall comply with the following requirements:
(a)
It shall meet the requirements for Grade A machines, as defined in AS 2193 for the
relevant range of compressive forces.
NOTE: The machine needs to be suitable for the range required since this test is normally
carried out at a lower range of force than AS 1012.9.
(b)
It shall be power operated and capable of applying compressive forces increasing
continuously at the rate of loading and in the manner specified in Clause 6.
(c)
The machine shall be fitted with a device for controlling rate of loading which can
operate at a rate of loading specified in Clause 6.
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
4.2 Flexure testing apparatus
The force shall be applied to the specimen through a frame containing two supporting
rollers and two loading rollers. The frame shall consist of two parts (upper and lower) each
of which shall be precisely located in the testing machine so that loading is applied evenly
and precisely at the third points of the span. This frame may be incorporated either in the
testing machine or in an accessory that can be used with, or between, the platens of a
suitable compression-testing machine.
The application of the force shall be through the spherical seat or a loading ball (see
Figure 1) that is centrally placed between the loading rollers.
The rollers shall be suitably articulated to ensure that—
(a)
the force is divided equally between the loading rollers;
(b)
the force is applied normal to the specimen surface; and
(c)
the specimen is not restrained or subject to torsion.
NOTE: This may be achieved by incorporating a suitable system of transverse rollers and either a
spherical seat or a ball in both the supporting group and loading group of rollers.
A suitable arrangement of the loading apparatus is illustrated in Figure 1.
The dimensions and spacing of the rollers shall comply with the following requirements:
(i)
Two hardened steel rollers of 38 mm to 40 mm nominal diameter shall be provided to
support the specimen. The centre-to-centre distance of the supporting rollers (L) shall
be in accordance with Table 1.
(ii)
Two hardened steel rollers of 38 mm to 40 mm nominal diameter shall be used to
apply the load at the third points of the supporting span. The centre-to-centre distance
of the loading rollers (l) shall be in accordance with Table 1.
(iii)
The length of both the supporting and loading rollers shall be at least equal to the
width of the specimen being tested.
To ensure that the rollers bear uniformly on the width of the specimen, the surface of
the rollers along any contact edge shall not deviate from a straight line by more than
±0.02 mm in 150 mm.
4.3 Measuring apparatus
Vernier calliper or ruler readable to at least 1 mm.
© Standards Australia
www.standards.com.au
3
AS 1012.11—2000
5 CONDITIONING OF TEST SPECIMENS PRIOR TO TEST
The specimen shall be cured in accordance with AS 1012.8.2 to ensure that the surface of
the specimen has been maintained wet for 48 h prior to testing and that they are saturated
and kept wet immediately prior to testing.
At the end of the conditioning period, the specimen shall be kept wet and shall be tested
promptly. The surfaces of the specimens that are loaded shall be free from grit, and all
surfaces shall be wiped, if necessary, to remove surplus water.
TABLE 1
CENTRE-TO-CENTRE DISTANCES OF THE SUPPORTING
AND LOADING ROLLERS
Centre-to-centre distance of rollers
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
Nominal size of specimens
mm
Supporting rollers (L)
mm
150 × 150
450 + 10, − 5
100 × 100
300 + 8, − 3
Loading rollers (l)
mm
L
±1
3
FIGURE 1 DIAGRAMMATIC VIEW OF A SUITABLE FLEXURE TESTING APPARATUS
6 PROCEDURE
The procedure shall be as follows:
www.standards.com.au
© Standards Australia
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
AS 1012.11—2000
4
(a)
Remove grit from the surface of the specimen that is loaded and, if necessary, wipe to
remove the surplus water.
(b)
Turn the specimen on its side with respect to its position as moulded and then centre
it on the supporting rollers. Although it is necessary to locate the specimen centrally
with respect to its width, it is neither necessary nor always desirable that it be located
centrally with respect to its length. The position of the specimen may be arranged
such as to avoid any defects that may occur near one end.
(c)
Bring the loading rollers into contact with the top, apply a seating load not exceeding
100 N, check the uniformity of bearing of the rollers, and mark their position on the
sides of the specimen before proceeding with the loading.
(d)
Apply the force without shock and increase continuously at a rate equivalent to
1 ±0.1 MPa/min extreme fibre stress until no increase in force can be sustained.
Record the maximum force applied to the specimen as indicated by the testing
machine.
(e)
Determine the average width and average depth of the specimen at the section of
failure to the nearest 1 mm.
(f)
Note the appearance of the concrete and the type of fracture, if the fracture is unusual.
(g)
If the fracture occurs outside the middle third of the span length, do not calculate the
modulus of rupture but measure and record the distance from the nearest supporting
roller to the section of failure.
7
CALCULATION
When the fracture occurs within the middle third of the specimen, the modulus of rupture
shall be calculated as follows:
f cf =
PL (1000)
BD 2
where
fcf
= modulus of rupture, in megapascals
P
= maximum applied force indicated by the testing machine, in kilonewtons
L
= span length, in millimetres
B
= average width of the specimen at the section of failure, in millimetres
D
= average depth of specimen at the section of failure, in millimetres
8 PRECISION STATEMENT
For pairs of beams made from the same sample, cured in similar conditions and tested in
accordance with this standard, the repeatability expressed as a percentage of the mean of
the two strengths obtained, is 18 percent at the 95 percent probability level.
NOTE: This statement on repeatability is based on limited Australian data and may be amended
when more data is collected.
9 RECORDS
The following information shall be recorded for each test specimen:
(a)
Identification of the concrete.
(b)
Job site or laboratory where tested.
© Standards Australia
www.standards.com.au
5
AS 1012.11—2000
(c)
Date and time of test.
(d)
Moisture condition of specimen, as received.
(e)
Any apparent defects of the specimen, as received.
(f)
Age of specimen at the date of test, if known.
(g)
Failure load.
(h)
Span length.
(i)
Average width and depth of the specimen at the section of failure.
(j)
Modulus of rupture, calculated to the nearest 0.1 MPa, or the position of the fracture,
if it occurs outside the middle third of the span length.
(k)
Appearance of the concrete in the fracture surface and the type of fracture, if these are
unusual.
(l)
Any other significant factors noted before, during or after testing.
(m)
Identification of the testing operator.
(n)
Reference to this Standard, i.e. AS 1012.11.
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
10 REPORT
The following information shall be reported:
(a)
Identification of the concrete.
(b)
Date and location of test.
(c)
Age of specimen at the date of test, if known.
(d)
Nominal size of specimen.
(e)
Modulus of rupture, calculated to the nearest 0.1 MPa, or the position of the fracture
if it occur outside the middle third of the span length.
(f)
Any apparent defects, any relevant comments on the moisture condition of the
specimen, as received, or any other significant factor(s) noted before, during or after
testing.
(g)
Reference to this Standard, i.e. AS 1012.11.
(h)
Such other information contained in the sampling records (see AS 1012.1) as may be
requested.
www.standards.com.au
© Standards Australia
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
AS 1012.11—2000
6
NOTES
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
7
NOTES
AS 1012.11—2000
AS 1012.11—2000
8
This Australian Standard was prepared by Technical Committee BD/42, Methods of Testing Concrete. It was approved on behalf of the
Council of Standards Australia on 28 April 2000 and published on 18 May 2000.
The following interests are represented on Committee BD/42:
Association of Consulting Engineers Australia
AUSTROADS
Australian Chamber of Commerce and Industry
Australian Pre-mixed Concrete Association
CSIRO—Building, Construction and Engineering
Cement and Concrete Association of Australia
Concrete Institute of Australia
National Association of Testing Authorities Australia
University of New South Wales
Licensed to E.S.SURESH on 04 Jun 2002. Single user licence only. Storage, distribution or use on network prohibited.
University of Technology, Sydney
Keeping Standards up-to-date
Standards are living documents which 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 issued. Standards may also be withdrawn.
It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have
been published since the Standard was purchased.
Detailed information about Standards can be found visiting the Standards Australia web site at www.standards.com.au and looking up the
relevant Standard in the on-line catalogue.
Alternatively, the printed Catalogue provides information current at 1 January each year, and the monthly magazine, The Australian
Standard, has a full listing of revisions and amendments published each month.
We also welcome suggestions for the improvement in our Standards, and especially encourage readers to notify us immediately of any
apparent inaccuracies or ambiguities. Contact us via email at mail@standards.com.au, or write to the Chief Executive, Standards
Australia International Ltd, PO Box 1055, Strathfield, NSW 2135.
Originated as AS A106—1985.
Previous edition AS 1012.11—1985.
Third edition 2000.
This Standard was issued in draft form for comment as DR 98462.
COPYRIGHT
© Standards Australia International
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 International Ltd
PO Box 1055, Strathfield, NSW 2135, Australia
ISBN 0 7337 3392 1
Printed in Australia