1、Designation: C806 18Standard Test Method forRestrained Expansion of Expansive Cement Mortar1This standard is issued under the fixed designation C806; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of lengthchanges of expansive cement mortar, while under restraint, dueto the development of inte
3、rnal forces resulting from hydrationof the cement.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 The text of this standard refer
4、ences notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of this standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theres
5、ponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.(WarningFresh hydraulic cement mixtures are caustic andmay cause burns to skin and tissue upon prolonged exposure.2)1
6、.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to
7、Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3A307 Specification for Carbon Steel Bolts, Studs, andThreaded Rod 60 000 PSI Tensile StrengthC109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C157/C157M Test Method for Leng
8、th Change of HardenedHydraulic-Cement Mortar and ConcreteC219 Terminology Relating to Hydraulic CementC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC490/C490M Practice for Use of Apparatus for the Deter-mination of Length Change of Hardened Cement Pa
9、ste,Mortar, and ConcreteC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC778 Specification for Standard SandC1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsF606/
10、F606M Test Methods for Determining the MechanicalProperties of Externally and Internally ThreadedFasteners, Washers, Direct Tension Indicators, and Rivets3. Terminology3.1 Definitions of terms used in this test method are given inTerminology C219.4. Apparatus4.1 MoldsThe molds for casting test speci
11、mens, whenused in conjunction with the restraining cage described in 4.2,shall provide for forming either 2 by 2 by 10-in. prisms havinga 10-in. gage length, or 50 by 50 by 250-mm prisms having a250-mm gage length. The molds shall otherwise conform to therequirements of Practice C490/C490M, except t
12、hat the gagestud holder, gage studs, and spacer screws described in thatspecification will not be used.4.2 Restraining Cage, consisting of a threaded steel rodwith steel end plates held in place by nuts as shown in Fig. 1.The rod shall be provided with cap nuts for prevention ofcorrosion. The rod sh
13、all conform to Specification A307 GradeA except, it shall support 1180-lbf (5249 N) proof load whentested in accordance with Method 1 of Test Methods F606/F606M.4.3 Length ComparatorThe length comparator for mea-suring length shall conform to and be used in accordance withthe requirements of Practic
14、e C490/C490M. If the terminals of1This test method is under the jurisdiction ofASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.13 on Special Cements.Current edition approved July 1, 2018. Published July 2018. Originally approvedin 1975. Last previous edition approved
15、 in 2012 as C806 12. DOI: 10.1520/C0806-18.2Section of Safety, Manual of Cement Testing, Annual Book of ASTM Standards,Vol 04.01.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
16、on, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization e
17、stablished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1the comparator are fitted with collars, they shall be such thatthe cap nuts on the ends of the thread
18、ed rod of the specimen donot rest on the collar during measuring.4.4 TamperThe tamper shall be made of nonabsorptive,nonabrasive material such as medium-hard rubber or seasonedoak wood, rendered nonabsorptive by immersion for 15 min inparaffin at approximately 392F (200C), and shall have a crosssect
19、ion of about12 by 1 in. (13 by 25 mm) and convenientlength of about 6 in. (150 mm). The tamping face of the tampershall be flat and at right angles to the length of the tamper.4.5 Apparatus for Demolding SpecimensApparatus simi-lar to that described in the Apparatus section of Test MethodC157/C157M,
20、 may be found useful for demolding specimens.4.6 Weights and Weighing DevicesScales used shall com-ply with Specification C1005.4.7 Glass Graduate that conforms to the requirements ofTest Method C109/C109M.4.8 Mixer, Bowl, and PaddleThe mixer shall be an elec-trically driven mechanical mixer of the
21、type equipped withpaddle and mixing bowl, as specified in the Apparatus sectionof Practice C305.4.9 TrowelThe trowel shall have a steel blade 4 to 6 in.(102 to 152 mm) in length, with straight edges.5. Temperature and Humidity5.1 The temperature of the air in the vicinity of the mixingoperation, the
22、 dry materials, mixing water, molds, base plates,mixing bowl, moist closet or moist room, and storage watershall not vary from 73.4F (23C) by more than 63F(61.7C).5.2 The relative humidity of the laboratory shall be not lessthan 50 %. The moist closet or moist room shall provide arelative humidity o
23、f not less that 95 %.6. Graded Standard Sand6.1 Sand used shall comply with the graded sand require-ment of Specification C778.Passing Sieve Percentage RetainedNo. 100 (150-m) 98 2No. 50 (300-m) 72 5No. 30 (600-m) 2 2No. 16 (1.18-mm) noneNOTE 1Segregation of Graded SandThe graded standard sandshould
24、 be handled in such a manner as to prevent segregation, sincevariations in the grading of the sand cause variations in the consistency ofthe mortar. In emptying sacks of sand into bins or in scooping sand out ofbins or sacks, care should be exercised to prevent the formation of moundsof sand or crat
25、ers in the sand, down the slopes of which the coarserparticles will roll. Bins should be of sufficient size to permit theseprecautions. Devices for drawing the sand from bins by gravity should notbe used.7. Test Specimen7.1 The test specimen shall bea2by2by10-in. prismhaving a 10-in. gage length, or
26、 a 50 by 50 by 250-mm prismhaving a 250-mm gage length. At least two specimens shall beprepared for each test.Dimension, in. (mm) Tolerance, in. (mm)A1134 (300) .B 10 (250)18 (3)C 2 (50) .D 1 (25) .E13132 (49)132 (1)F6364 (24.5) .G38 (10) .FIG. 1 Restraining CageC806 1828. Preparation and Assembly o
27、f Specimen Molds andRestraining Cage8.1 Install the cap nuts firmly in place on the ends of therestraining rods and measure the restraining rods for lengthwhile they are at a temperature of 73.4 6 1F (23.0 6 0.5C).8.2 The edges of the end plates of the restraining cage thatcontact the sides and bott
28、om of the mold shall be thinlycovered with a heavy mineral oil or light cup grease such aspetrolatum. After assembly of the molds, place a restrainingcage in each compartment. Seal the contact lines between theouter sides and base plate of the molds with paraffin ormicro-crystalline wax. Thinly cove
29、r the interior faces of themolds with mineral oil and remove any oil or grease from therestraining cage rod and end plates.9. Proportioning and Mixing of Mortars9.1 Proportion the standard mortar by using one part ofcement to 2.75 parts of graded standard sand by mass. Mix800 g of cement, 2200 g of
30、graded standard sand, and 400 mLof water to produce a batch sufficient for two test specimens.9.2 Mix in accordance with the procedure for mixingmortars given in Practice C305. Upon completion of mixing,shake the mixing paddle into the mixing bowl to remove excessmortar.10. Molding Specimens10.1 Sta
31、rt molding specimens immediately after completionof mixing. Place the mortar in the mold in two layers with thefirst layer just covering the restraining rod and the second layerslightly overfilling the mold. Compact each layer by tamping.Work the mortar into the corners, around the restraining rod,w
32、ithout striking the rod, and along the surfaces of the moldwith the tamper until a homogeneous specimen is obtained.After the top layer has been compacted, strike-off the mortarflush with the top of the mold, and smooth the surface with afew strokes of the trowel.11. Curing of Specimens11.1 Immediat
33、ely after completion of molding, cover thespecimens with a polyethylene sheet, or other suitable materialfor preventing loss or gain of moisture, at the surface of thespecimens. The cover should make contact with the surface ofthe mortar. Place the specimens in the moist room or moistcabinet.11.2 Re
34、move the specimens from the molds at an age of 6614 h after the addition of water to the cement during themixing operation (Note 2). Particular care must be exercised inthis operation in order not to damage the specimens because oftheir low strength at this age. It is preferable to use thedemolding
35、devices referred to in 4.5 for freeing specimensfrom the base and side plates.NOTE 2At this time comparator readings may be made. Althoughthese readings may differ slightly from the initial reading made on therestraining rod prior to molding the specimen, it can serve as a check onthe initial readin
36、g which should be used as the basis for calculating thelength change.11.3 Cure the specimens in lime-saturated water at 73.4 63.0F (23.0 6 1.7C) until they have reached an age of 7 days6 1 h, including the period in the molds, except that thetemperature of the curing water shall be 73.4 6 1F (23.0 6
37、0.5C) for at least the last 15 min. At the end of this period,remove the specimens from the water one at a time, wipe witha damp cloth, and immediately make comparator readings withthe cap nuts in place.11.4 Return the specimens to curing in lime-saturated waterat 73.4 6 3.0F (23.0 6 1.7C) until the
38、y have reached an ageof 28 days including the period in the molds. At the end of thecuring period, make comparator readings immediately after thespecimens have been subjected to about 15 min of storage inwater at 73.4 6 1.0F (23.06 0.5C) and in the same manneras described in 11.3.12. Calculation12.1
39、 Calculate the expansion or shrinkage at any age asfollows:Ex5Lx2 Li10 250!3100 (1)where:Ex= expansion at x age, %,Lx= comparator reading of specimen at x age referencebar comparator reading, in. (mm), andLi= initial comparator reading of restraining rod refer-ence bar comparator reading, in. (mm).1
40、3. Report13.1 Report the following information:13.1.1 Number of specimens for each condition and datemolded,13.1.2 Source and identification of cement.13.1.3 Age of specimen for each observation for lengthchange,13.1.4 Length-change data, expressed as linear expansion orcontraction based on the leng
41、th of the specimen at time ofmolding shall be reported as percent change dimension to thenearest 0.001 %, and13.1.5 Any other pertinent information.14. Precision and Bias414.1 Precision:14.1.1 Within Batch PrecisionThe standard deviation oftwo bars made from the same batch and tested together wasfou
42、nd to be 0.00276 %. Therefore two bars made from thesame batch should not differ from each other by more than0.008 % length change.514.1.2 Single Operator PrecisionThe single operator stan-dard deviation has been found to be 0.0038 at seven and twentyeight days age, based on the average of two bars.
43、 Therefore the4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:C01-1001.5These numbers represent, respectively, the (1s) and (d2s) limits as described inPractice C670.C806 183results of two properly conducted tests by the same op
44、erator onthe same material should not differ by more than 0.011 %length change.514.1.3 Multilaboratory PrecisionThe multilaboratorystandard deviation has been found to be 0.0093 at seven andtwenty eight days age, based on the average of two bars.Therefore the results of two properly conducted tests
45、on thesame material in two different laboratories should not differ bymore than 0.026 % length change.514.2 BiasA bias statement cannot be prepared due to thefact that absolute standards are not available.15. Keywords15.1 cement mortar; expansive cement; restrained expan-sionASTM International takes
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47、onsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addresse
48、d to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the
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