BS 1881-122-2011 Testing concrete Method for determination of water absorption《测试混凝土 吸水性测定方法》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 1881-122:2011Testing concretePart 122: Method for determinationof water absorptionPublishing and copyright informationThe BSI copyright notice displayed in this document indic

2、ates when the documentwas last issued. BSI 2011ISBN 978 0 580 74627 7ICS 91.100.30The following BSI references relate to the work on this standard:Committee reference B/517Draft for comment 11/30242744 DCPublication historyFirst edition January 1983Second (present) edition July 2011BS 1881-122:2011

3、BRITISH STANDARDContentsForeword iii1 Scope 12 Normative references 13 Terms and definitions 14 Apparatus 15 Test specimens 26 Procedure 37 Calculation and expression of results 38 Test report 4Bibliography 5List of figuresFigure 1 Correction factor 4Summary of pagesThis document comprises a front c

4、over, an inside front cover, pages i to iv,pages 1 to 6, an inside back cover and a back cover.BRITISH STANDARD BS 1881-122:2011 BSI 2011 iBRITISH STANDARDBS 1881-122:2011This page deliberately left blankii BSI 2011ForewordPublishing informationThis Part of BS 1881 was published by BSI and came into

5、 effect on 31 July 2011.It was prepared by Subcommittee B/517/1/30, Concrete production and testing,under the authority of Technical Committee B/517, Concrete and relatedproducts. A list of organizations represented on these committees can beobtained on request to their secretary.SupersessionThis pa

6、rt of BS 1881 supersedes BS 1881-122:1983, which is withdrawn.Relationship with other publicationsBS 1881 contains test methods for concrete currently used in the UnitedKingdom which are not covered by BS EN 12350, BS EN 12390 or BS EN 12504.Reference is made to the relevant part of BS EN 12350, BS

7、EN 12390 andBS EN 12504 where appropriate. These test methods may be used in conjunctionwith BS EN 206-1.BS 1881 is published in the following parts: Part 113, Method for making and curing no-fines cubes; Part 119, Method for determination of compressive strength using portionsof beams broken in fle

8、xure (equivalent cube method); Part 122, Method for determination of water absorption; Part 124, Methods for analysis of hardened concrete; Part 125, Method for mixing and sampling fresh concrete in the laboratory; Part 128, Method for analysis of fresh concrete; Part 129, Method for the determinati

9、on of density of partially compactedsemi-dry fresh concrete; Part 204, Recommendations on the use of electromagnetic covermeters; Part 206, Recommendations for determination of strain in concrete; Part 207, Recommendations for the assessment of concrete strength bynear-to-surface tests; Part 208, Re

10、commendations for the initial surface absorption of concrete; Part 209, Recommendations for the measurement of dynamic modulus ofelasticity of concrete; and DD 216, Method for the determination of chloride content of freshconcrete.Information about this documentThis is a full revision of the standar

11、d for determination of water absorption intocores and has been extended to cover the testing of cast specimens.BS ISO 5725-2 gives further information on the determination of repeatabilityand reproducibility.BRITISH STANDARD BS 1881-122:2011 BSI 2011 iiiHazard warningsCAUTION When cement is mixed wi

12、th water, alkali is released. Takeprecautions to avoid dry cement entering the eyes, mouth and nose whilstmixing concrete. Prevent skin contact with wet cement or concrete bywearing suitable protective clothing. If cement or concrete enters the eye,immediately wash it out thoroughly with clean water

13、 and seek medicaltreatment without delay. Wash wet concrete off the skin immediately.Use of this documentIt has been assumed in the preparation of this British Standard that theexecution of its provisions will be entrusted to appropriately qualified andexperienced people, for whose use it has been p

14、roduced.Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Itsrequirements are expressed in sentences in which the principal auxiliary verb is“shall”.Commentary, explanation and general informative material is presented insmaller italic type, and do

15、es not constitute a normative element.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legalobligations.BRITISH

16、STANDARDBS 1881-122:2011iv BSI 20111 ScopeThis Part of BS 1881 specifies a method for the determination of waterabsorption of concrete specimens cored from a structure or a precastcomponent.The method may also be used to determine the water absorption of concretecast into prisms or cylinders where t

17、he surface to volume ratio can be calculatedand where no point in the specimen is more than 50 mm from a free surface.The measured water absorption of the specimen is corrected to that equivalentto a surface to volume ratio of a core 75 mm long with a diameter of 75 mm.NOTE Absorption values for cas

18、t specimens are normally slightly lower than thosefor a core from the same concrete but the difference can be more significant if theaggregate is absorbent.2 Normative referencesThe following referenced documents are indispensable for the application ofthis document. For dated references, only the e

19、dition cited applies. For undatedreferences, the latest edition of the referenced document (including anyamendments) applies.BS 8500-1 Concrete Complementary British Standard to BS EN 206-1 Part 1: Method of specifying and guidance for the specifierBS 8500-2 Concrete Complementary British Standard t

20、o BS EN 206-1 Part 2: Specification for constituent materials and concreteBS EN 206-1, Concrete Part 1: Specification, performance, production andconformityBS EN 12390-1, Testing hardened concrete Part 1: Shape, dimensions and otherrequirements for specimens and mouldsBS EN 12390-2, Testing hardened

21、 concrete Part 2: Making and curingspecimens for strength testsBS EN 12390-7, Testing hardened concrete Part 7: Density of hardened concreteBS EN 12504-1, Testing concrete in structures Part 1: Cored specimens Taking,examining and testing in compression3 Terms and definitionsFor the purposes of this

22、 Part of this British Standard the definitions given inBS 8500-1, BS 8500-2 and BS EN 206-1 apply.4 Apparatus4.1 Balance, capable of weighing specimens up to 5 kg to an accuracy of0.001 kg. It shall be calibrated on first use and at least annually thereafter, usingweights of which the accuracy can b

23、e traced to the national standard of massand shall be checked after relocation or disturbance. A certificate stating theaccuracy shall be obtained from the organization carrying out the check.4.2 Coring machine, with a cylindrical bit having an impregnated or set diamondcutting edge for cutting a 75

24、mm 3 mm diameter core.4.3 Ventilated drying oven, controlled to maintain a temperature of105 C 5 C, and such that the specimens can be placed in the oven asdescribed in 6.1.BRITISH STANDARD BS 1881-122:2011 BSI 2011 14.4 Curing tank, at least 125 mm deep, containing water from a potable supplymainta

25、ined at a temperature of 20 C 2 C.4.5 Dry airtight vessel, (e.g. desiccator) of sufficient size to take the set of threespecimens to be tested.4.6 Cubes or cylinders, when used, conforming to BS EN 12390-1. Cube sidesshall not exceed 100 mm and cylinders shall not have a diameter exceeding100 mm.5 T

26、est specimens5.1 Cored specimensCores shall be taken according to BS EN 12504-1.To ensure the sample is representative, a set of three specimens shall beobtained by coring from the full thickness of the concrete when this isbetween 32 mm and 150 mm, or by obtaining a core 75 mm long when thethicknes

27、s of the specimen is greater than 150 mm. The diameter of each coreshall be 75 mm 3 mm.Each core shall be marked clearly with its identification mark in indelible inkimmediately after cutting, and the orientation of each core shall be determined.Cores that have been broken out of larger samples shal

28、l have the broken endstrimmed approximately square with the axis.NOTE One end of each specimen should preferably be from one of the faces whichwould normally be exposed when the unit is in use.5.2 Cast specimensTo ensure the sample is representative, at least three cubes or cylinders shall beprepare

29、d from fresh concrete in accordance with BS EN 12390-2. Particular careshall be taken to keep the use of mould release compounds to a minimum.NOTE Preferably mould release compounds should not be used at all.When it is necessary to use a mould release agent, the surface shall be rinsedwith clean wat

30、er immediately after demoulding, then it shall be brushed with aweak detergent solution followed by a final water rinse to remove any residualrelease agent.If there is any indication of surface staining, a water repellent surface orretardation of the cement paste resulting from the use of mould oils

31、, thespecimen shall be rejected.After demoulding and cleaning, the specimens shall be stored in a curing tankkept at 20 C 2 C until required for testing.5.3 Measurement of densityThe density of the specimens shall be measured in accordance withBS EN 12390-7. Use the saturated procedure for cast spec

32、imens. Use either theas-received or saturated procedure for cored specimens.5.4 Measurement of dimensionsThe dimensions of the specimen shall be measured in accordance withBS EN 12390-1.BRITISH STANDARDBS 1881-122:20112 BSI 20115.5 Age of specimens at testUnless specified otherwise, the test for abs

33、orption shall be made when the ageof the concrete is 28 days to 32 days. Therefore the drying of the specimensshall begin at an age of 24 days to 28 days.NOTE If the absorption test is carried out on concrete less than 28 days old anappreciably higher value might be obtained. Conversely, the absorpt

34、ion at agesgreater than 28 days might be appreciably less. These variations are dependent,amongst other factors, on the rate of hydration of the cement.6 Procedure6.1 Place the three specimens in the drying oven (4.3) not less than 25 mm fromany heating surface or from each other, and so that air ca

35、n access all theirsurfaces. Do not place further specimens in the oven once the drying process hasbegun.6.2 Dry the specimens in the oven for 72 h 2 h.6.3 On removal from the oven (4.2), cool each specimen for 24 h 0.5 h in thedry airtight vessel (4.5).6.4 Weigh and record the mass of each specimen

36、immediately after cooling.6.5 Completely immerse each specimen in the tank (4.4) with its longitudinal axishorizontal and at a depth at which there is 25 mm 5 mm of water above topof the specimen.6.6 Immerse the specimens in the water for 30 min 0.5 min, unless otherwisespecified.6.7 Upon removal of

37、 each specimen, shake it to remove the bulk of the surfacewater and dry it with a cloth as rapidly as possible until all free water isremoved from the surface.6.8 Weigh each specimen and record its mass.NOTE Where the effectiveness of water resisting admixtures or pore blockers arebeing established,

38、 the water absorption rate should be obtained using the followingcumulative immersion periods: 10, 30, 60, 120 min, unless otherwise specified, withthe same specimens being used and returned to the tank after each measurement.7 Calculation and expression of resultsThe measured absorption of each spe

39、cimen shall be calculated as the increase inmass resulting from immersion expressed as a percentage of the mass of the dryspecimen.A correction factor according to the surface to volume ratio of the specimenshall be obtained using the formula:correction factor5volumesmm3dsurface area (mm3d 12.5In th

40、e case of cores with a diameter of 75 mm 3 mm the correction factor shallbe obtained from the curve shown in Figure 1 according to the length of thespecimen.The product of this correction factor and the measured absorption shall beknown as the corrected absorption, this being the equivalent absorpti

41、on of acore of 75 mm diameter with a length of 75 mm. The results shall be expressedto the nearest 0.1%.BRITISH STANDARD BS 1881-122:2011 BSI 2011 38 Test reportThe test report shall include:a) identification of the test specimen;b) type of specimen, core or cast cube or cylinder;c) condition of spe

42、cimen when received (include poor compaction andhoneycombing);d) details of reinforcement (if any);e) orientation of the specimen to the structure;f) date of receipt of the specimen;g) dimensions of the specimen;h) conditions of storage and curing until test date;i) date of beginning of tests (placi

43、ng in oven);j) density of the specimen (as-received or saturated and method ofdetermining volume);k) mass of each oven-dried specimen;l) mass of each specimen after the specified immersion period(s);m) measured absorptions;n) corrected absorptions and mean value;o) any specified deviations from the

44、standard procedure;p) declaration by the person technically responsible for the test that it wascarried out in accordance with this standard, except as noted in item o).NOTE The test report can also include:a) building project;b) part or component of the building;c) details of the concrete. other in

45、formation, e.g. absorption time graph,comparison with a control specimen, etc.Figure 1 Correction factorBRITISH STANDARDBS 1881-122:20114 BSI 2011BibliographyFor dated references, only the edition cited applies. For undated references, thelatest edition of the referenced document (including any amen

46、dments) applies.BS EN 12350, Testing fresh concreteBS EN 12390, Testing hardened concreteBS EN 12504, Testing concrete in structuresBS ISO 5725-2, Accuracy (trueness and precision) of measurement methods andresults Part 2: Basic methods for the determination of repeatability andreproducibility of a

47、standard measurement methodBRITISH STANDARD BS 1881-122:2011 BSI 2011 5BRITISH STANDARDBS 1881-122:20116 BSI 2011 This page deliberately left blankThis page deliberately left blankBSI is the independent national body responsible for preparing British Standardsand other standards-related publications

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