1、Designation: C 806 04Standard Test Method forRestrained Expansion of Expansive Cement Mortar1This standard is issued under the fixed designation C 806; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 i
3、nternal forces resulting from hydrationof the cement.1.2 The values stated in non-SI units are to be regarded asthe standard. When both the inch-pound units and the SI unitsare present, the non-SI units are to be regarded as the standard.The values in SI units are approximate, are listed for informa
4、-tion only, and will likely provide different values than theinch-pound units.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and deter
5、mine the applica-bility of regulatory limitations prior to use. (WarningFreshhydraulic cement mixtures are caustic and may cause burns toskin and tissue upon prolonged exposure.2)2. Referenced Documents2.1 ASTM Standards:3A 307 Specification for Carbon Steel Bolts and Studs,60 000 PSI Tensile Streng
6、thC 157 Test Method for Length Change of Hardened-Hydraulic-Cement, Mortar, and ConcreteC 219 Terminology Relating to Hydraulic CementC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC 490 Practice for Use of Apparatus for the Determinationof Length Ch
7、ange of Hardened Cement Paste, Mortar, andConcreteC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC 778 Specification for Standard SandC 1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTest
8、ing of Hydraulic CementsF 606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers, and Rivets3. Terminology3.1 Definitions of terms used in this test method are given inTerminology C 219.4. Apparatus4.1 MoldsThe molds for casting test speci
9、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 C 490, except that t
10、he gage studholder, gage studs, and spacer screws described in that speci-fication 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 shall
11、 conform to Specification A 307 GradeA except, it shall support 1180-lbf (5249 N) proof load whentested in accordance with Method 1 of Test Methods F 606.4.3 Length ComparatorThe length comparator for mea-suring length shall conform to and be used in accordance withthe requirements of Practice C 490
12、. If the terminals of thecomparator are fitted with collars, they shall be such that thecap nuts on the ends of the threaded rod of the specimen do notrest on the collar during measuring.4.4 TamperThe tamper shall be made of nonabsorptive,nonabrasive material such as medium-hard rubber or seasonedoa
13、k wood, rendered nonabsorptive by immersion for 15 min inparaffin at approximately 392 F (200 C), and shall have across section of about12 by 1 in. (13 by 25 mm) andconvenient length of about 6 in. (150 mm). The tamping faceof the tamper shall be flat and at right angles to the length ofthe tamper.4
14、.5 Apparatus for Demolding SpecimensApparatus simi-lar to that described in the Apparatus section of Test MethodC 157, may be found useful for demolding specimens.1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.13 on Spe
15、cial Cements.Current edition approved July 1, 2004. Published July 2004. Originally approvedin 1975. Last previous edition approved in 1995 as C 806 95.2Section of Safety, Manual of Cement Testing, Annual Book of ASTM Standards,Vol 04.01.3For referenced ASTM standards, visit the ASTM website, www.as
16、tm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.6 Weig
17、hts and Weighing DevicesScales used shall com-ply with Specification C 1005.NOTE 1Generally defined, the sensibility reciprocal is the change inload required to change the position of rest of the indicating element orelements of a nonautomatic-indicating scale a definite amount at any load.4.7 Glass
18、 Graduates, of suitable capacities (preferably largeenough to measure the mixing water in a single operation) shallbe made to deliver the indicated volume at 68 F (20 C). Thepermissible variation shall be 62 mL. These graduates shall besubdivided to at least 5 mL, except that the graduation linesmay
19、 be omitted for the lowest 10 mL for a 250-mL graduateand the lowest 25 mL for a 500-mL graduate. The maingraduation lines shall be circles and shall be numbered. Theleast graduations shall extend at least one seventh of the wayaround, and intermediate graduations shall extend at least onefifth of t
20、he way around.4.8 Mixer, Bowl, and PaddleThe mixer shall be an elec-trically driven mechanical mixer of the type equipped withpaddle and mixing bowl, as specified in the Apparatus sectionof Practice C 305.4.9 TrowelThe trowel shall have a steel blade 4 to 6 in.(102 to 152 mm) in length, with straigh
21、t edges.5. Temperature and Humidity5.1 The temperature of the air in the vicinity of the mixingoperation, the dry materials, mixing water, molds, base plates,mixing bowl, moist closet or moist room, and storage watershall not vary from 73.4 F (23 C) by more than 63F(61.7C).5.2 The relative humidity
22、of the laboratory shall be not lessthan 50 %. The moist closet or moist room shall provide arelative humidity of not less that 95 %.6. Graded Standard Sand6.1 Sand used shall comply with the graded sand require-ment of Specification C 778.Passing Sieve Percentage RetainedNo. 100 (150-m) 98 6 2No. 50
23、 (300-m) 72 6 5No. 30 (600-m) 2 6 2No. 16 (1.18-mm) noneNOTE 2Segregation of Graded SandThe graded standard sandshould 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 bi
24、ns or in scooping sand out ofbins or sacks, care should be exercised to prevent the formation of moundsof sand or craters 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 grav
25、ity should notbe used.7. Test Specimen7.1 The test specimen shall bea2by2by10-in. prismhaving a 10-in. gage length, or a 50 by 50 by 250-mm prismDimension, 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 CageC8
26、06042having a 250-mm gage length. At least two specimens shall beprepared for each test.8. Preparation and Assembly of 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 temperat
27、ure of 73.4 6 1 F (23.0 6 0.5 C).8.2 The edges of the end plates of the restraining cage thatcontact the sides and bottom 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
28、the contact lines between theouter sides and base plate of the molds with paraffin ormicro-crystalline wax. Thinly cover 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 s
29、tandard mortar by using one part ofcement to 2.75 parts of graded standard sand by mass. Mix 800g of cement, 2200 g of graded standard sand, and 400 mL ofwater to produce a batch sufficient for two test specimens.9.2 Mix in accordance with the procedure for mixingmortars given in Practice C 305. Upo
30、n completion of mixing,shake the mixing paddle into the mixing bowl to remove excessmortar.10. Molding Specimens10.1 Start 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 layersli
31、ghtly overfilling the mold. Compact each layer by tamping.Work the mortar into the corners, around the restraining rod,without 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 mortarflu
32、sh with the top of the mold, and smooth the surface with afew strokes of the trowel.11. Curing of Specimens11.1 Immediately 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. Th
33、e cover should make contact with the surface ofthe mortar. Place the specimens in the moist room or moistcabinet.11.2 Remove the specimens from the molds at an age of 6614 h after the addition of water to the cement during themixing operation (Note 3). Particular care must be exercised inthis operat
34、ion in order not to damage the specimens because oftheir low strength at this age. It is preferable to use thedemolding devices referred to in 4.5 for freeing specimensfrom the base and side plates.NOTE 3At this time comparator readings may be made. Althoughthese readings may differ slightly from th
35、e initial reading made on therestraining rod prior to molding the specimen, it can serve as a check onthe initial reading which should be used as the basis for calculating thelength change.11.3 Cure the specimens in lime-saturated water at 73.463.0 F (23.0 6 1.7 C) until they have reached an age of
36、7 days6 1 h, including the period in the molds, except that thetemperature of the curing water shall be 73.4 6 1 F (23.0 60.5 C) 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
37、withthe cap nuts in place.11.4 Return the specimens to curing in lime-saturated waterat 73.4 6 3.0 F (23.0 6 1.7 C) until they 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
38、to about 15 min of storage inwater at 73.4 6 1.0 F (23.06 0.5 C) and in the same manneras described in 11.3.12. Calculation12.1 Calculate the expansion or shrinkage at any age asfollows:Ex5Lx2 Li10 250!3 100 (1)where:Ex= expansion at x age, %,Lx= comparator reading of specimen at x age referencebar
39、comparator reading, in. (mm), andLi= initial comparator reading of restrainingrod reference bar comparator reading, in. (mm).13. 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
40、for each observation for lengthchange,13.1.4 Length-change data, expressed as linear expansion orcontraction based on the length 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.
41、1 Precision:14.1.1 Within Batch PrecisionThe standard deviation oftwo bars made from the same batch and tested together wasfound 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
42、 operatorstandard deviation has been found to be 0.0038 at seven andtwenty eight days age, based on the average of two bars.Therefore the results of two properly conducted tests by the4Supporting data are available from ASTM Headquarters. Request RR: C01-1001.5These numbers represent, respectively,
43、the (1s) and (d2s) limits as described inPractice C 670.C806043same operator on the same material should not differ by morethan 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 ave
44、rage of two bars.Therefore the results of two properly conducted tests 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
45、mortar; expansive cement; restrainedexpansionASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, an
46、d the riskof infringement of such rights, are entirely their own responsibility.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 revisi
47、on of this standard or for additional standardsand should be addressed 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 sh
48、ouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C806044
