1、BSI Standards PublicationBS ISO 18650-2:2014Building constructionmachinery and equipment Concrete mixersPart 2: Procedure for examination of mixingefficiencyBS ISO 18650-2:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18650-2:2014.The UK participation in
2、 its preparation was entrusted to TechnicalCommittee B/513/1, Earth moving machinery (International).A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are resp
3、onsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 86197 0ICS 91.220Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Po
4、licy and Strategy Committee on 31 October 2014.Amendments issued since publicationDate Text affectedBS ISO 18650-2:2014 ISO 2014Building construction machinery and equipment Concrete mixers Part 2: Procedure for examination of mixing efficiencyMachines et matriels pour la construction des btiments M
5、alaxeurs de bton Partie 2: Mode opratoire pour la dtermination de lefficacit de malaxageINTERNATIONAL STANDARDISO18650-2Second edition2014-09-15Reference numberISO 18650-2:2014(E)BS ISO 18650-2:2014ISO 18650-2:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights rese
6、rved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IS
7、O at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18650-2:2014ISO 18650-2:2014(E) ISO 2014 All rights reserved
8、 iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Requirements for mixer verified . 15 Mixing performance test 25.1 General . 25.2 Concrete mix preparation 35.3 Sampling . 35.4 Variance tests . 96 Evaluation of test results .137 Test report 138
9、 Final remarks 178.1 Filling ratio of tested mixer . 178.2 Optimization of mixing time. 17Bibliography .19BS ISO 18650-2:2014ISO 18650-2:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of pre
10、paring International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in
11、 liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC
12、 Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesAttention is drawn to the possibility that som
13、e of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declara
14、tions received. www.iso.org/patentsAny trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs
15、 adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 195, Building construction machinery and equipment, Subcommittee SC 1, Machinery and equipment for concrete work.
16、This second edition cancels and replaces the first edition (ISO 18650-2:2006), of which it constitutes a minor revision. The main changes are: updated normative references in Clause 2; notes added to Clause 4 re requirements for mixer verified; an alternative coarse aggregates size added to 5.2; not
17、es added to Figure 3; mesh screen/coarse aggregate modified size in 5.4.1.1 d), Figure 7, 5.4.1.3, Tables 1 and 4; corrected intersections on regression curves in Figure 8.ISO 18650 consists of the following parts, under the general title Building construction machinery and equipment Concrete mixers
18、: Part 1: Vocabulary and general specifications Part 2: Procedure for examination of mixing efficiencyiv ISO 2014 All rights reservedBS ISO 18650-2:2014ISO 18650-2:2014(E)IntroductionThis part of ISO 18650 deals with the testing of the mixing capabilities of concrete mixers, characterized as the rec
19、ommended mixing time.The test consists of the determination of the variance of the mortar, coarse aggregate and air content, and the consistency of concrete mix samples, drawn after an assumed mixing time.Compressive strength is also tested.The measure of a concrete mixers efficiency is the value of
20、 the variance of the above parameters, after the assumed mixing time.This part of ISO 18650 provides for the preparation of concrete mix, sampling, execution of particular tests, criteria of test result evaluation and the test report. ISO 2014 All rights reserved vBS ISO 18650-2:2014BS ISO 18650-2:2
21、014Building construction machinery and equipment Concrete mixers Part 2: Procedure for examination of mixing efficiency1 ScopeThis part of ISO 18650 specifies the procedure and requirements for examination of the mixing efficiency of batch-type and continuous-type concrete mixers as defined in ISO 1
22、8650-1. It is applicable to concrete mixers having a rated capacity greater than or equal to 70/50.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest
23、 edition of the referenced document (including any amendments) applies.ISO 1920-1, Testing of concrete Part 1: Sampling of fresh concreteISO 1920-2, Testing of concrete Part 2: Properties of fresh concreteISO 1920-3, Testing of concrete Part 3: Making and curing test specimensISO 1920-4, Testing of
24、concrete Part 4: Strength of hardened concreteISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire clothISO 6783, Coarse aggregates for concrete Determination of particle density and water absorption Hydrostatic balance methodISO 7033, Fine and coarse aggregat
25、es for concrete Determination of the particle mass-per-volume and water absorption Pycnometer methodISO 11375, Building construction machinery and equipment Terms and definitionsISO 18650-1, Building construction machinery and equipment Concrete mixers Part 1: Vocabulary and general specifications3
26、Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 18650-1 and ISO 11375 apply.4 Requirements for mixer verifiedThe design and execution of the whole structure of the mixer and its components, such as the mixing chamber (drum, pan, or trough), rotor with b
27、lades or paddle agitator(s), their directions of rotation, charging and discharging devices (if any), should be verified according to the manufacturers instructions.It shall be determined that the number of revolutions per minute of a drum or mixing tools conforms to the manufacturers specification.
28、INTERNATIONAL STANDARD ISO 18650-2:2014(E) ISO 2014 All rights reserved 1BS ISO 18650-2:2014ISO 18650-2:2014(E)The drive system should be able to restart 5 min after being stopped when the mixer has completed the mixing of the test batch as specified in 5.2.NOTE 1 The “restart” is for the additional
29、 mixing and does not warrant a series of restarts for the next batches.The mixer shall be discharged according to its design or as specified by the manufacturer. The closure of the mixing chamber shall be so designed that the loss of the mix before discharge, i.e. during charging and mixing, remains
30、 below 0,5 %.NOTE 2 The “below 0,5%” does not apply to the 1st batch which has more adhesion of mortar to the inner wall of drum.5 Mixing performance test5.1 GeneralThe mixing efficiency is determined by the uniformity of the concrete mix and the compressive strength of the concrete cubes or cylinde
31、rs, sampled after mixing time. The determination of the uniformity of the concrete mix includes the following variance tests on the sampled specimens:a) air content;b) content of mortar per unit volume;c) content of coarse aggregate per unit volume;d) consistency (slump).The values of the concrete-m
32、ix component content (air, mortar, coarse aggregate), determined as the test results, as well as the consistency and compressive strength, are subsequently used for calculation of their variances.For calculating the variance, X, of the considered components content and other features, expressed as a
33、 percentage, the following formula is applied:XXXXX=+1212100 whereX1is the value of component content, slump and compressive strength received from portion 1 or 2 larger value of X1and X2;X2is the value of component content, slump and compressive strength received from portion 1 or 2 smaller value o
34、f X1and X2.To explain the physical sense of this formula, it can be transformed as follows:XXXXXXXXXX=+=+12121221222In this form it represents the variance of a subject parameter in two portions against its average value.For evaluation of the test results, the particular variance values are compared
35、 with the acceptable results according to Clause 6.2 ISO 2014 All rights reservedBS ISO 18650-2:2014ISO 18650-2:2014(E)5.2 Concrete mix preparationThe test concrete to be used for the mixing performance test should be specified by the concrete manufacturer or testing laboratory with the following co
36、nditions: coarse aggregates up to 20 mm or 25 mm, slump (80 30) mm, air content (4,5 1,5) % and nominal compressive strength (25 5) N/mm2. In case of difficulty in obtaining of the assumed air content, an appropriate admixture may be used.The quantity of components usually corresponds to the rating
37、capacity declared by the mixers manufacturer.The constituent materials are to be weighed with measuring incertitude limits of 3 %.The sequence of a mixer charging with particular components should be as specified in the manufacturers instruction. If there is no such instruction, the method of chargi
38、ng should be noted in the test report.The charging of a mixer with constituent materials shall be carried out with a minimum loss of materials.The mixing time shall be as specified by the manufacturer. If no such specification is available, the following approximate values depending on the mixer typ
39、e and its capacity are recommended:a) For batch-type gravity mixers: rated capacity 1,0 m3and less, 60 s; rated capacity above 1,0 m3, 5 s added to 60 s for every 0,5 m3increase.b) For batch-type compulsory mixers: rated capacity 3,0 m3and less, 30 s; rated capacity above 3,0 m3, 15 s added to 30 s
40、for every 1,5 m3increase.c) For continuous mixers: a mixing time corresponding to the duration of the concrete mix in the mixing chamber, which shall be at least 10 s.5.3 Sampling5.3.1 GeneralTwo portions of the concrete mix are sampled directly from the mixing chamber immediately after ensured mixi
41、ng time (see Figures 2, 3, 4 and 5). Where the direct sampling from inside the mixing chamber is difficult, the sampling may be done from the concrete mix discharged to the hopper (see Figures 6 and 7). The volume of the sample (portion) should be a minimum of 20 l for batch mixers and 100 l for con
42、tinuous mixers (see 5.3.4). Afterwards, the specimens for particular variance tests are prepared. ISO 2014 All rights reserved 3BS ISO 18650-2:2014ISO 18650-2:2014(E)KeyP1, P2concrete mix portion sampled from the mixerSAC1, SAC2specimens for air content testSMG1, SMG2specimens for air content test u
43、sed for coarse aggregate and mortar content testing in further sequenceS1,S2,S3specimens for compressive strength test (three cubes or cylinders from each portion)S1,S2,S3specimens for consistency (slump) testSS1, SS2Figure 1 General scheme of sampling5.3.2 Batch-type compulsory mixers5.3.2.1 Pan-ty
44、pe mixersIn pan-type mixers the samples (portions) are taken from concentric circles. Figure 2 shows an example of sampling in a turbo mixer.4 ISO 2014 All rights reservedBS ISO 18650-2:2014ISO 18650-2:2014(E)Key1 centre portion2 edge portion3 centre cylinder covering dead mixing areaFigure 2 Sampli
45、ng in turbo mixerIn other types of pan-type mixers, those not having a centre cylinder covering the dead mixing area, the radius separating two concentric circles is equal to a quarter of the inner pan diameter.5.3.2.2 Paddle mixersExamples of sampling in paddles mixers with one or two paddle agitat
46、ors are shown in the Figure 3.a) One-agitator mixer ISO 2014 All rights reserved 5BS ISO 18650-2:2014ISO 18650-2:2014(E)b) Two-agitator mixerKey1 front portion2 rear portion3 centre portionKey items 1, 2 and 3 designate the portion of concrete being mixed in the drum. They shall be sampled right aft
47、er discharge.Item 3 designates that portion to be sampled only in case it is impossible to sample from the portion designated 1 or 2.Figure 3 Sampling in paddle-type mixer5.3.3 Gravity mixersThe concrete mix portions are taken to the receiving containers from the beginning and the end of the concret
48、e discharge stream, as shown in Figure 4.A batch during discharging is conventionally divided into three parts (beginning, middle and end) from which the corresponding portions are taken.a) Tipping drum mixer6 ISO 2014 All rights reservedBS ISO 18650-2:2014ISO 18650-2:2014(E)b) Discharging chute dru
49、m mixerc) Reversing drum mixerKey1 beginning portion2 middle portion3 end portionFigure 4 Sampling in gravity mixers5.3.4 Continuous mixersThe first-sampled portion should be from a stable flow, just at the moment when the discharged concrete reaches output capacity, with another sample being taken 4 min after the first. The volume of each portion should be at least 100 l. See Figure 5. ISO 2014 All rights reserved 7BS ISO 18650-2:2014ISO 18650
