1、Designation:C86216Standard Practice forPreparing Refractory Concrete Specimens by Casting1This standard is issued under the fixed designation C862;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in
2、parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This practice covers the mixing,casting and curing ofmonolithic
3、refractory concrete specimens under laboratoryconditions for use in further testing.It does not apply tomonolithic castable refractories intended primarily for gunningapplications.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematical
4、conversions to SI units that are provided for information onlyand are not considered standard.1.3 Various specimen sizes are required for specific testmethods.Refer to these test methods to determine the size andnumber of specimens,which will be required from the sample.1.4 This standard does not pu
5、rport 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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C133
6、Test Methods for Cold Crushing Strength and Modu-lus of Rupture of RefractoriesC192/C192M Practice for Making and Curing Concrete TestSpecimens in the Laboratory3.Significance and Use3.1 This practice is used to standardize mixing,moldconditions,placement and curing of refractory concrete speci-mens
7、 to be used for testing and evaluation under other testmethods.3.2 This practice standardizes laboratory conditions forproducing refractory concrete specimens to minimizelaboratory-to-laboratory variation and does not attempt toduplicate the conditions of field installations.3.3 This practice can be
8、 used for the preparation of speci-mens used in referee testing.4.Apparatus and Conditions4.1 Laboratory ConditionsThe laboratory ambient shouldbe controlled between 70 and 80F(20 and 27C)(Note 1)andfrom 40 to 60%relative humidity for preconditioning materi-als and equipment,batching and mixing cast
9、ing test specimens,stripping molds,and testing specimens.Report laboratorytemperature and relative humidity with physical test results ifother than specified.NOTE1A 5 to 6F temperature difference can drastically change theset time of a mix.It is a good practice to always record ambienttemperature co
10、nditions for each cast.4.2 BalancesAppropriately sized scales having a sensitiv-ity of 0.2%of the related batch size.4.3 Castable MixersAn electrically operated mechanicalmixer(Fig.1)may be used for preparing castable batches forcasting specimens.A 2-ft3(0.057-m3)mixing bowl or a 212-ft3(0.071-m3)co
11、ncrete mixer has sufficient capacity to mix about1 ft3(0.0285 m3)of refractory castable.The smallest batchesrequired for casting 1-in.(25-mm)square bars can be mixed ina 0.10-ft3(0.0028-m3)bowl available with bench mixers.Sizemixing bowl to contain from 50 to 75%volume loading withthe dry batch.Cast
12、able water requirement variation becomesmore significant as dry volume loadings drop below 40%because the water required to wet the bowl surfaces changesmore rapidly with decreasing volume loadings.4.4 MoldsTypical molds are 9 by 2 by 2 in.and 2 by 2 by2 in.made from metal,plastic or rubber and are
13、watertight,rigid,and removable.There are commercially available moldsfrom concrete testing suppliers and other sources.Molds maybe reusable or for single use.Although brick-sized shapes maybe cut with a diamond saw to obtain a specific size,it ispreferable to fabricate the desired shape.The smallest
14、 molddimension should be a minimum of three times the largestaggregate diameter,as specified in Practice C192/C192M.Insome cases,when smaller specimens are required and grainsizing does not allow for smaller castings,cut specimens maybe used.See Table 1.1This practice is under the jurisdiction ofAST
15、M Committee C08 on Refractoriesand is the direct responsibility of Subcommittee C08.09 on Monolithics.Current edition approved Nov.1,2016.Published November 2016.Originallyapproved in 1977.Last previous edition approved in 2008 as C862 02(2008).DOI:10.1520/C0862-16.2For referenced ASTM standards,vis
16、it the ASTM website,www.astm.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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.5 CalipersSuitable for measuring internal longitudinalmold dimensions and subsequent specimen length size to thenearest 0.01 in.(0.25 mm).4.6 Mold LubricantEither paraffin or silicone-base
