ASTM_C_865_-_13.pdf

Designation:C86513Standard Practice forFiring Refractory Concrete Specimens1This standard is issued under the fixed designation C865;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 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 Department of Defense.1.Scope1.1 This practice covers the firing of specimens made fromrefractory concretes(castable refractories)in accordance withPractice C862 for cast specimens.The procedure is alsorecommended for heating rates to be used for high-temperaturetest methods such as Methods C16,C583,etc.,when thesemethods are used to test refractory concretes.1.2 The values stated in inch-pound units are to be regardedas the standard.The values given in parentheses are forinformation only.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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C16 Test Method for Load Testing Refractory Shapes atHigh TemperaturesC583 Test Method for Modulus of Rupture of RefractoryMaterials at Elevated TemperaturesC862 Practice for Preparing Refractory Concrete Specimensby CastingE230 Specification and Temperature-Electromotive Force(EMF)Tables for Standardized Thermocouples3.Significance and Use3.1 This practice is used to standardize the firing conditionsof refractory concrete specimens prepared in accordance withPractice C862.The standards are set down to minimizelaboratory-to-laboratory variation and do not attempt to dupli-cate any particular field applications.4.Apparatus4.1 Kiln,equipped with instruments capable of controllingthe heating rate of the kiln at 100 to 700F(55 to 380C)/h(see6.5)and holding the soak temperature to 610F(5.5C)of thenominal soak temperature.For temperatures up to 2500F(1370C)an electrically heated kiln is preferred,but gas-oroil-fired kilns can be used for all temperatures,provided theheating rates specified can be maintained,the flame of theburners does not impinge directly on any specimen,and thefurnace atmosphere contains a minimum of 0.5%oxygen with0%combustibles.5.Preparation of Samples5.1 Samples are prepared by casting in accordance withMethods C862.If the sample size of the cast specimen is thesame as that specified for the test,it can be used directly.However,cutting samples of the required size from larger castblocks will often be necessary(Note 1).In this case,it isrecommended that the samples be cut with a diamond saw.After cutting,the samples should be dried at 230F(110C)fora minimum of 18 h.All cut samples should have sharp edgesand corners and should not show pull-out of grains on the cutsurfaces.For some low-strength castables,drying prior tocutting may be needed to increase their strength and resistanceto pull-outs.NOTE1Specimens cut from the interior of large cement bondedcastables shapes may be stronger than specimens cut from small castshapes because the interior of large cast shapes are exposed to highpressure steam during dryout which causes more complete hydration ofthe cement.5.2 Some types of castables,especially those containingaggregates of a relatively low hardness(such as lightweightcastables),may be cut on a dry saw.This procedure isacceptable provided that specimens with sharp corners andedges,which show no signs of grain pull-out at the cutsurfaces,are obtained.6.Procedure6.1 Label all specimens with ceramic ink or ceramic cray-ons.6.2 Place the specimens in the kiln so that each specimenwill rest on the surface formed by its longest and smallest1This practice is under the jurisdiction ofASTM Committee C08 on Refractoriesand is the direct responsibility of Subcommittee C08.09 on Monolithics.Current edition approved Sept.1,2013.Published October 2013.Originallyapproved in 1977.Last previous edition approved in 2007 as C865 02(2007).DOI:10.1520/C0865-13.2For referenced ASTM standards,visit 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 dimension(that is,the 9 by 212-in.(230 by 65-mm)surface for9-in.straight,or the 6 by 1-in.(152 by 25-mm)surface for 6 by1 by 1 in.samples).Support each specimen on a flat supportingbrick,which does not soften or shrink at the intended soaktemperature.Place between the test specimens and the support-ing brick a layer of suitable refractory material that is nonre-active under the test conditions and passes a No.16(1.18-mm)sieve and is retai