ASTM_C_1656_-_13.pdf

Designation:C165613Standard Guide forMeasuring the Reactivity of Hydraulic Refractory Castablesusing Exothermic Profile1This standard is issued under the fixed designation C1656;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.1.Scope1.1 This guide applies to all castables with a reactive bindersystem that produces a measurable heat profile during thesetting and hardening process.The majority of these systemswill have calcium aluminate cement as one component of thebinder system.1.2 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:2C401 Classification of Alumina and Alumina-SilicateCastable RefractoriesC71 Terminology Relating to RefractoriesC862 Practice for Preparing Refractory Concrete Specimensby Casting3.Terminology3.1 Definitions:3.1.1 EP exothermic profile,nthe curve generated byplotting temperature of the embedded thermocouple versustime.3.1.2 LCC,nLow cement castable.4.Significance and Use4.1 The heat of hydration of a calcium aluminate basedcastable is liberated over a short period of time(as comparedto Portland cement).This makes it easy to measure the heatprofile using off-the-shelf thermocouple equipment.4.2 The heat profile can be used to make inferences aboutthe setting and strength gain behavior of a castable andsometimes the working time of a castable.4.3 Factors that should be controlled when comparing twocastables include:size,shape and mass of cast object,starttemperature of the mix,temperature of environment,and thethermal conductivity of the environment.If these factors areheld constant,then the two castables heat profiles can becompared.4.4 The temperature increase created by the castable exo-thermic reaction shall be at least 2.0C more than the normalfluctuation of the laboratory temperature so that the time of thisincrease is easily discernible to the user.4.5 Varying the amount of cement in the castable,theamount of water,the type and quantity of admixtures,and soforth,will change the shape,maximum temperature and time tomaximum temperature of the curve.4.6 Following is an example of a curve generated for anLCC(see Fig.1)that does exhibit two peaks,the first onemarking the end of working time.In this curve one could alsoinfer that the start temperature of the mix was 24C and alsothat the hydraulic strength gain reaction was significantlystarted,but not completed by 6 h.5.Apparatus5.1 Mixing equipment as prescribed in C862.5.2 Type T thermocouple(Type J,E,or K are also accept-able but not preferred due to range of sensitivity.Other typescannot be used.)Wire ends should be joined by solder orwelding.Simple twisting is not recommended due to thepotential for inaccurate readings.5.3 Thermocouple sheathing(optional).5.4 Voltmeter,data acquisition card or some other instru-ment to read the thermocouple mV value.5.5 Container for storage of castable during heat profilegeneration and constant temperature environment in which tostore the container.5.6 Personal computer loaded with above card will makecurve generation easier.1This guide is under the jurisdiction of ASTM Committee C08 on Refractoriesand is the direct responsibility of Subcommittee C08.09 on Monolithics.Current edition approved April 1,2013.Published June 2013.Originallyapproved in 2007.Last previous edition approved in 2007 as C1656 07.DOI:10.1520/C1656-13.2For 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 6.Hazards6.1 There are no known hazards associated with the method.Safe practice should be used when mixing the castable.Castable MSDS should be consulted to determine if anyhazards exist with the castable.7.Procedure7.1 Prepare the castable according to the manufacturersmixing instructions noting the time of water addition.Forcomparison testing,the water addition should produce acomparable consistency of the castables.7.2 If the entire sample will not be used for the EPgeneration,grab select a representative sample of required sizefrom the mixing bowl by successive quartering when the mixeris turned off.7.3 Place castable in a container.Place container in anenvironment with constant temperature.7.4 Place thermocouple in the center of the castable in thecontainer.Use of a sheath is not required but will allow foreasier removal of th