1、Designation:D7792/D7792M15Standard Practice forFreeze/Thaw Conditioning of Pultruded Fiber ReinforcedPolymer(FRP)Composites Used in Structural Designs1This standard is issued under the fixed designation D7792/D7792M;the number immediately following the designation indicates theyear of original adopt
2、ion or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 In general,it is feasible that the mechanical properties ofFRP composites will b
3、e affected by environmental conditionssuch as freeze/thaw cycling.In order to make reliable com-parisons between different materials under freeze/thaw envi-ronmental conditions,it is necessary to standardize the freeze/thaw conditions to which specimens of these materials aresubjected prior to and d
4、uring testing.This practice definesprocedures for freeze/thaw conditioning of pultruded FRPcomposites intended for use in structural design applications.1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard.Thevalues stated in each system may not
5、 be exact equivalents;therefore,each system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with the standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of
6、 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:2D618 Practice for Conditioning Plastics for TestingD3918 Terminology Relating to Reinforced Plastic Pul-t
7、ruded ProductsD6641/D6641M Test Method for Compressive Properties ofPolymer Matrix Composite Materials Using a CombinedLoading Compression(CLC)Test FixtureD7290 Practice for Evaluating Material Property Character-istic Values for Polymeric Composites for Civil Engineer-ing Structural ApplicationsD77
8、45 Practice for Testing Pultruded Composites3.Terminology3.1 Definitions:3.1.1 standard laboratory temperaturea temperature of23 6 2C 73.4 6 3.6F.3.1.2 standard laboratory atmospherean atmosphere hav-ing a temperature of 23 6 2C 73.4 6 3.6F and a relativehumidity of 50 6 10%.3.1.3 freeze/thaw resist
9、ancethe ability of a thermosetpultruded composite to withstand repeated water exposure andsubsequent freeze cycling for 100 freeze/thaw cycles.Thisability will be quantified in terms of the%retention of themechanical property of interest as compared to samples ex-posed to water for a comparable time
10、 without subsequentfreeze/thaw cycling.3.2 Terminology relating to pultruded composites is foundin Terminology D3918.4.Significance and Use4.1 The freeze/thaw conditioning procedures prescribed inthis practice are designed to provide a standard procedure to beused to evaluate and compare the effect
11、of 100 freeze/thawcycles under controlled laboratory conditions on pultrudedFRP composites to be used in structural design applications.The conditioning procedures prescribed in this practice aredesigned to obtain reproducible results to compare and evalu-ate these materials but are not intended to
12、produce equilibriumconditions or actual service conditions for these materials.5.Sampling5.1 Sampling shall be in accordance with the locations fromwhich test specimens shall be taken from the reinforcedpultruded composites as defined in Practice D7745.1This test method is under the jurisdiction of
13、ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.18 on Reinforced Thermoset-ting Plastics.Current edition approved Sept.1,2015.Published October 2015.DOI:10.1520/D7792_D7792M-15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Custom
14、er 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 5.2 Sampling shall be in accordance with the
15、 ASTM testmethods for the specific mechanical properties to be deter-mined.36.Test Specimens6.1 The numbers and types of test specimens shall be inaccordance with the ASTM test methods for the specificmechanical properties to be determined.If Practice D7290 is tobe used to determine characteristic v
16、alues,at least ten samplesare needed for the control and ten samples are needed for thefreeze/thaw exposure for a total of at least 20 samples.6.2 Test specimens shall be machined or otherwise fabri-cated to the test coupon geometry specified by the ASTM testmethod for the properties to be determined prior to theirexposure to the environmental conditioning.6.3 The thickness of the test specimens shall be the originalproduct thickness without any machining of the surface.Thespecimen thickness nee
