ASTM_C_661_-_15.pdf

Designation:C66115Standard Test Method forIndentation Hardness of Elastomeric-Type Sealants byMeans of a Durometer1This standard is issued under the fixed designation C661;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 U.S.Department of Defense.1.Scope1.1 This test method describes a laboratory procedure fordetermining indentation hardness of joint sealing compounds,(single-and multicomponent),intended for use in buildingconstruction.1.2 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.1.3 The committee with jurisdiction over this standard is notaware of any comparable standards published by other orga-nizations.1.4 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsD2240 Test Method for Rubber PropertyDurometer Hard-ness3.Terminology3.1 DefinitionsSee Terminology C717 for applicable defi-nitions of the following terms:compound;elastomeric;hard-ness;joint;sealant,non-sag;sealant,self-leveling,and stan-dard conditions.4.Significance and Use4.1 The results obtained by this test method are simply ameasure of the indentation into the sealant material of theindentor under load;they are not generally considered ameasure of abrasion or wear resistance of the sealant.5.Apparatus5.1 Durometer,Type A-2,with a dial graduated in units from0 to 100.(See Test Method D2240 for a description of theindentor and a method of calibration of the durometer.)5.2 Rectangular Brass Frame,with inside dimensions 130by 40 by 6 mm(approximately 5 by 112by14in.).5.3 Aluminum Plates,two 16 to 24 gage,80 by 150 mm(approximately 3 by 6 in.).5.4 Thin-Bladed Knife.5.5 Chamber,capable of maintaining 38 6 2C(100 63.5F)and 95%relative humidity.5.6 Metal Straightedge.6.Standard Test Conditions6.1 Unless otherwise specified by those authorizing thetests,testing is conducted under standard conditions as definedin Terminology C717.7.Procedure7.1 Test for Hardness of Multicomponent Sealants:7.1.1 Condition at least 250 g of base compound andappropriate amounts of curing agent for at least 24 h atstandard conditions;then mix the components thoroughly for 5min.7.1.2 Fill the brass frame,after centering it on the aluminumplate,with a portion of the conditioned compound and strike itoff flat with a metal straightedge.Lift the frame from thesealant after separating it by running a thin-bladed knife alongthe inside of the frame.Prepare two such specimens and curethem for 14 days at standard conditions.NOTE1In the case of a self-leveling sealant or compound,do not liftthe brass frame until the sealant is sufficiently cured so that it will notspread on the plate.7.1.3 At the end of the curing period,take three hardnessreadings on each specimen at standard conditions.Hold thedurometer on the surface of the specimen and press it firmly1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.20 onGeneral Test Methods.Current edition approved June 1,2015.Published July 2014.Originally approvedin 1970.Last previous edition approved in 2011 as C661 06(2011).DOI:10.1520/C0661-15.2For 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 against the surface using a force of about 1.3 kgf(3 lbf).Keepthe pressure foot parallel to the surface of the specimen.Takethe instantaneous indentation reading immediately after mak-ing firm contact between the pressure foot and the specimen.After taking the first reading,shift the durometer(or specimen)to a new position in order to avoid errors due to fatigue andsurface effects from the previous indentation.Take readings onsmooth portions of the surface no closer than 13 mm(12in.)from the edges of the sealant pat and also no closer than 25 mm(1 in.)from each other.Note the individual values,eachrounded off to the nearest unit on the scale.NOTE2The highest precision in this test can be obtained when thedurometer is supported by a rigid stand and a dead weight is fasteneddirectly to the instrument with the center of gravity of the weight actingin line of the indentor point.A freely acting total dead