BS 1881-130-2013 Testing concrete Part 130 Method for temperature-matched curing of concrete specimens《混凝土测试 第130部分 混凝土试样固化温度对比方法》.pdf

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1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 1881-130:2013Testing concrete Part 130: Method fortemperature-matched curingof concrete specimensPublishing and copyright informationThe BSI copyright notice displayed in this

2、 document indicates when the documentwas last issued. The British Standards Institution 2013Published by BSI Standards Limited 2013ISBN 978 0 580 77926 8ICS 91.100.30The following BSI references relate to the work on this standard:Committee reference B/517Draft for comment 12/30258720 DCPublication

3、historyFirst edition November 1996Second (present) edition January 2013Amendments issued since publicationDate Text affectedBS 1881-130:2013 BRITISH STANDARDContentsForeword iiIntroduction 11 Scope 22 Normative References 23 Terms and definitions 24 Apparatus 25 Method 36 Report 4AnnexesAnnex A (inf

4、ormative) Recording the temperature history of a concreteelement 5Bibliography 6Summary of pagesThis document comprises a front cover, an inside front cover, pages i to iv,pages 1 to 6, an inside back cover and a back cover.BRITISH STANDARD BS 1881-130:2013 The British Standards Institution 2013 iFo

5、rewordPublishing informationThis part of BS 1881 is published by BSI Standards Limited, under licence fromThe British Standards Institution, and came into effect on 31 January 2013. Itwas prepared by Subcommittee B/517/1, Concrete production and testing, underthe authority of Technical Committee B/5

6、17, Concrete. A list of organizationsrepresented on this committee can be obtained on request to its secretary.SupersessionThis part of BS 1881 supersedes BS 1881-130:1996, which is withdrawn.Relationship with other publicationsBS 1881 is published in the following parts: BS 1881-113, Method for mak

7、ing and curing no-fines cubes; BS 1881-119, Method for determination of compressive strength usingportions of beams broken in flexure (equivalent cube method); BS 1881-122, Method for determination of water absorption; BS 1881-124, Methods for analysis of hardened concrete; BS 1881-125, Method for m

8、ixing and sampling fresh concrete in thelaboratory; BS 1881-128, Method for analysis of fresh concrete; BS 1881-129, Method for the determination of density of partiallycompacted semi-dry fresh concrete; BS 1881-130, Method for temperature matched curing of concretespecimens; BS 1881-131, Methods fo

9、r testing cement in a reference concrete; BS 1881-201, Guide to the use of non-destructive methods of test forhardened concrete; BS 1881-204, Recommendations on the use of electromagnetic covermeters; BS 1881-206, Recommendations for determination of strain in concrete; BS 1881-207, Recommendations

10、for the assessment of concrete strength bynear-to-surface tests; BS 1881-208, Recommendations for the initial surface absorption ofconcrete; BS 1881-209, Recommendations for the measurement of dynamic modulusof elasticity of concrete; DD 216, Determination of chloride content of fresh concrete.Prese

11、ntational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Itsmethods are expressed as a set of instructions, a description, or in sentences inwhich the principal auxiliary verb is “shall”.Commentary, explanation and general informative material is presented ins

12、maller italic type, and does not constitute a normative element.BRITISH STANDARDBS 1881-130:2013ii The British Standards Institution 2013Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct a

13、pplication.Compliance with a British Standard cannot confer immunity from legalobligations.BRITISH STANDARD BS 1881-130:2013 The British Standards Institution 2013 iiiBRITISH STANDARDBS 1881-130:2013This page deliberately left blankiv The British Standards Institution 2013IntroductionDuring the peri

14、od between fresh concrete in an element hardening, and itbeing subjected to working loads, an estimate of the in-situ strength might berequired for a number of reasons, these include: to provide information on the gain of concrete strength in cold conditions; to determine the striking time for verti

15、cal and soffit formwork; to determine the time at which pre-stressing operations may be started to determine the time at which a member may be subjected to all or part ofthe working load; and to provide information on the effects of temperature on the long termstrength of the concrete.The in-situ cu

16、be or cylinder strength (as defined in BS 6089) differs from thestandard strength of water-stored cubes or cylinders cured at 20 C (as definedin BS EN 12390-2) for a number of reasons, including: variations in mix proportions within or between batches; differences in compaction; differences in moist

17、ure conditions during curing; and differences in temperature history.This test procedure only addresses the difference in temperature history.The temperature history of concrete in an element depends on the types andquantities of cement, the thermal properties of the concrete, the size and shapeof t

18、he section, the insulating properties of the formwork, the ambienttemperature conditions and the concrete placing temperature. Because of this,standard cubes or cylinders might not give a reliable indication of the concretestrength in the element, particularly at early ages, where large differences

19、intemperature history can occur between cubes or cylinders stored at 20 C, andthe concrete in the element. An alternative method is therefore needed forestimating the early-age strength of the concrete in the element underconsideration.Several methods are in use, but these vary considerably in accur

20、acy andappropriateness for the following reasons. Tests conforming to BS EN 12504-2 and BS EN 12504-3 are only suitable forestimating the concrete strength near to the surface as they are dependenton impact, resistance, or rupture of the concrete surface. However, as this isthe concrete that protect

21、s the reinforcement, it is often the most highlystressed part of the cast section. Specimens cured alongside the cast section provide a safe and reasonablemeans by which the strength of the cast section can be estimated only if thecast section is thin and not insulated. In larger cast sections, spec

22、imens curedalongside substantially underestimate the early-age strength of the castsection. By matching the temperature of water in a curing bath to the rise and fallof temperature in a concrete element, specimens cured in the bath aresubjected to the same temperature history as the concrete at a se

23、lectedpoint in the element. When tested for strength, these specimens give amore accurate estimate of the concrete strength at a selected point in theelement at the time of testing. This method of curing specimens is termedtemperature-matched curing.BRITISH STANDARD BS 1881-130:2013 The British Stan

24、dards Institution 2013 1A feature of using temperature-matched curing is that a record is obtained ofthe rise and fall in concrete temperature due to the hydration of the cement.Depending on the particular conditions, the control of early-age thermalcracking might require conformity to a maximum pea

25、k temperature, a maximumfall from peak temperature to mean ambient temperature and/or a maximumtemperature difference. Where the heat of hydration of the concrete causes thetemperature to exceed 70 C, the properties of the concrete might be affected.In order to assess the possibility of damage to co

26、ncrete by any of the abovephenomena, recording the temperature at various locations in the structure isoften advantageous. Such an investigation may be undertaken either inconjunction with, or independently of temperature-matched curing. Annex Adescribes how such temperature histories can be recorde

27、d.1 ScopeThis part of BS 1881 describes the method for curing concrete cubes or cylindersso that they follow the concrete temperature at a pre-selected position in aconcrete element.Guidance on recording the temperature history at other positions in a concreteelement is also given.2 Normative Refere

28、ncesThe following documents, in whole or in part, are normatively referenced in thisdocument and are indispensable for its application. For dated references, onlythe edition cited applies. For undated references, the latest edition of thereferenced document (including any amendments) applies.BS EN 1

29、2350-1, Testing fresh concrete Part 1: SamplingBS EN 12390-1, Testing hardened concrete Part 1: Shape, dimensions and otherrequirements for specimens and mouldsBS EN 12390-2, Testing hardened concrete Part 2: Making and curingspecimens for strength testsBS EN 12390-3, Testing hardened concrete Part

30、3: Compressive strength of testspecimens3 Terms and definitionsFor the purposes of this part of BS 1881, the terms and definitions given inBS EN 12350-1 apply.4 Apparatus4.1 Cube or cylinder moulds, conforming to BS EN 12390-1 (as appropriate to themaximum aggregate size in use) together with a cove

31、r plate.NOTE The function of the cover plate is to prevent concrete being washed fromthe specimen surface by the circulating water, but not necessarily to provide acomplete seal. Mould bases make suitable cover plates.4.2 Water bath (or curing tank), of sufficient capacity to contain at least foursp

32、ecimen moulds.4.3 Water heater, capable of raising the temperature of the water in the filledbath at a rate of 10 C/h.BRITISH STANDARDBS 1881-130:20132 The British Standards Institution 20134.4 Agitating device, for circulating the water in the bath to ensure an eventemperature distribution.4.5 Temp

33、erature sensor for concrete, accurate to 1 C, compatible with andforming part of the control equipment described in 4.8, for monitoring thetemperature of the concrete at the location at which the in-situ strength is to beestimated.4.6 Temperature sensor for water bath, accurate to 1 C, compatible wi

34、th andforming part of the control equipment described in 4.8.4.7 Recorder(s), capable of recording the outputs from the temperature sensorslocated in the water bath and concrete continuously, or at intervals notexceeding 15 min in the first 24 h of curing, and 30 min thereafter.4.8 Control equipment

35、, capable of maintaining the temperature of the waterbath to 2 C when compared with the concrete temperature, and capable offunctioning satisfactorily up to temperatures of 80 C.NOTE 1 Provided the quantity of water in the bath does not exceed 150 L, naturalcooling of an un-lagged bath is usually su

36、fficient to keep its temperature the sameas that measured at the concrete temperature sensor whilst the concretetemperature is falling.NOTE 2 The temperature sensor in the water bath should be located well awayfrom heating element.NOTE 3 Advice on methods suitable for recording temperatures is given

37、 in A.4.5 Method5.1 Positioning the concrete temperature sensor(s)5.1.1 Agree the position(s) at which the temperature sensor(s) are to be placedwithin the element with the person(s) requesting that the test is carried out.5.1.2 Position the sensor at the selected location preferably before placing

38、theconcrete, or within 30 min of placing.5.1.3 Ensure that when the chosen position (see 5.1.1) is near an external face,the tip of the sensor is at least 25 mm and preferably 50 mm away from anyformed or exposed surface.NOTE When assessing formwork striking times or the time for starting pre-stress

39、ingor loading for example, the location chosen should be representative of the coolerparts of the element. This is to ensure that the matched cubes/cylinders give therequired strength.5.2 Sampling and curing5.2.1 Take a representative sample of the concrete being placed in the elementin accordance w

40、ith BS EN 12350-1.5.2.2 Cast at least four specimens from this concrete into in accordance withBS EN 12390-2.5.2.3 Wipe the top edge of each mould clean and apply the cover plate. Placethe filled moulds immediately into the water bath immersing them completely.5.2.4 Ensure that the initial temperatu

41、re of the water bath is within 1 C of theconcrete temperature.BRITISH STANDARD BS 1881-130:2013 The British Standards Institution 2013 35.2.5 Switch on the control and recording equipment at least 30 min before theconcrete temperature sensor is covered with concrete.5.3 Strength testing5.3.1 At the

42、required ages, remove at least two specimens, de-mould and testthem immediately for compressive strength in accordance with BS EN 12390-3.5.3.2 Record the results individually for each specimen.6 Report6.1 GeneralThe report shall state that the test specimens were cured in accordance with thispart o

43、f BS 1881, and in particular that inspection of the temperatures recordedfrom the sensors indicates that the control equipment used was in accordancewith 4.8.6.2 Information to be included in the test reportThe report shall include the following:a) identification of the concrete element in the struc

44、ture;b) location of the concrete temperature sensor within the element;c) method of curing of the element, e.g. time of retention of shutters,additional measures;d) date and time of commencement of test;e) identification marks on the test specimens;f) nominal size of test specimens;g) age of specime

45、ns in days (if less than 3 days, in hours);h) strength of cubes/cylinders in N/mm (see 5.3);i) a note of any malfunctions of the equipment;j) calibration status of the test equipment;k) any deviations from this standard; andl) documentation of the sampling method, if available.NOTE The following inf

46、ormation should be made available if requested at the timeof issuing instructions for the test:a) appearance of the test sample;b) temperature history of the element recorded by the concrete temperaturesensor; andc) maturity at testing, stating what maturity function was used.BRITISH STANDARDBS 1881

47、-130:20134 The British Standards Institution 2013Annex A(informative)Recording the temperature history of a concreteelementA.1 GeneralIn addition to the temperatures monitored by the temperature-matched curingsystem, it is often desirable to monitor and record the temperature history invarious other

48、 positions of large concrete elements. This may be achieved by theuse of additional temperature sensors connected to a suitable recorder.A.2 Additional temperature sensorsThe positioning of any additional temperature sensors should be agreed withthe person(s) requesting that the test is carried out

49、with due consideration tothe data required and its application. Fixing the measuring tip of sensors toreinforcement should be avoided as conduction of heat through thereinforcement can give false readings of the temperature of the concrete.Thermocouples for example should be attached such that the measuringjunction is placed at least 25 mm from the reinforcement. For recording ambientair temperatures, sensors should be positioned so that they avoid direct sunlight.A.3 AccuracyMeasurements from any additional tempe