1、BRITISH STANDARD BS 6319-10: 1987 Testing of resin compositions for use in construction Part 10: Method for measurement of temperature of deflection under a bending stress UDC 691.342+691.537:620.174.251.12BS6319-10:1987 This British Standard, having been prepared under the directionof the Civil Eng
2、ineeringand Building Structures Standards Committee,was published underthe authority of the BoardofBSI and comes into effecton 31 March 1987 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference CSB/20 Draft for comment 85/11831 DC ISBN 0 580 15776 8 Commi
3、ttees responsible for this British Standard The preparation of this British Standard was entrusted by the Civil Engineering and Building Structures Standards Committee (CSB/-) to Technical Committee CSB/20, upon which the following bodies were represented: British Adhesives and Sealants Association
4、British Plastics Federation Concrete Society Construction Industry Research and Information Association County Surveyors Society Department of the Environment (Building Research Establishment) Department of Transport (Highways) Federation of Epoxy Resin Formulators and Applicators Ltd. Institution o
5、f Civil Engineers Institution of Highways and Transportation Institution of Structural Engineers Plastics and Rubber Institute Society of Chemical Industry Amendments issued since publication Amd. No. Date of issue CommentsBS6319-10:1987 BSI 08-1999 i Contents Page Committees responsible Inside fron
6、t cover Foreword ii 1 Scope 1 2 Principle 1 3 Test specimens 1 4 Procedure 1 5 Test report 1 Appendix A Effect of temperature on resin compositions 2 Appendix B Degree of cure 2 Publications referred to Inside back coverBS6319-10:1987 ii BSI 08-1999 Foreword This Part of BS6319 has been prepared und
7、er the direction of the Civil Engineering and Building Structures Standards Committee. It describes a method for measurement of the temperature of deflection under a bending stress, alternatively known as the heat distortion temperature (HDT), and is one of a series of Parts describing methods for m
8、easuring basic physical properties of resin based materials. This method is derived from methods121A and121B of BS2782:Methods121A to121C:1976 which have been adapted to the testing of resin compositions used in construction. The precision of this test method has not been considered in detail becaus
9、e it has been derived from tests which are already established. The method is suitable for quality control and comparative purposes but it does not alone provide sufficient information for direct use in structural design. This Part of BS6319 should be read in conjunction with Part1 which provides ge
10、neral information and describes a method for preparing test specimens. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer imm
11、unity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the
12、 amendment table on the inside front cover.BS6319-10:1987 BSI 08-1999 1 1 Scope This Part of BS6319 describes a method of measurement for the temperature of deflection under a bending stress (alternatively known as heat distortion temperature) for resin based mortars and concretes cast in the form o
13、f rectangular prisms. The method is not applicable for compositions which contain aggregate larger than1.7mm (seenoteto3.2). NOTE 1The effect of temperature on resin compositions is an important but complex subject and interpretation of test data requires care. Several relevant points are discussed
14、in Appendix A and Appendix B. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle The principle of this method is the determination of the temperature, referred to in this standard as the heat distortion temperature (HDT), at which a spe
15、cified deformation occurs when the test specimen, in the form of a rectangular prism, is subjected to a specified bending stress and conditions of uniform rate of temperature increase. 3 Test specimens NOTEA number of standard test methods have been published for the determination of the heat distor
16、tion temperature of plastics materials using specimens in the form of rectangular prisms which are subjected to three-point loading. These standards have adopted similar rates of raising the temperature of the specimen (2.0 0.2 C/min for the heat transfer medium), the same fibre stresses (1.8MPa,264
17、psi and0.45MPa,66psi) and, for a given specimen depth, the same deformation (0.25mm for a specimen depth of12.8mm to13.0mm). However, no standard refers specifically to filled thermosetting resin compositions and, furthermore, for the types of materials which are specified, the recommended specimen
18、dimensions often vary from standard to standard. The present method is derived from methods121A and121B of BS2782:Methods121A to121C:1976. 3.1 Preparation of specimens The preparation of specimens, including the conditioning, proportioning and mixing of materials, and the conditioning and filling of
19、 moulds shall be in accordance with BS6319-1. 3.2 Dimensions of test specimens Specimen dimensions of110mm (minimum) 12.8mm 12.8mm shall be used for compositions containing aggregate that, when sampled in accordance with BS812-1, completely passes through a1.7mm BS410 test sieve (mesh number10). NOT
20、EAlthough in principle, the specimen size can be increased in order to accommodate larger aggregate, practical difficulties can then arise due to the modifications which have to be made to the test procedure. 3.3 Curing of specimens Any desired curing regime may be used and shall be declared in the
21、test report. Any conditioning as part of the curing regime shall be declared in the test report. 4 Procedure Using two specimens, weigh each to the nearest0.1g. Use either of the following procedures: procedure A: the procedure given for method121A in BS2782:Methods121A to121C; procedure B: the proc
22、edure given for method121B in BS2782:Methods121A to121C. If only one bending stress is to be utilized use preferably procedure A (maximum fibre stress1.8MPa). Adjust the initial temperature of the heating medium to the curing temperature, or to20 C, whichever is the lower. 5 Test report The followin
23、g information shall be included in the test report: a) date of sample preparation; b) date of test; c) a complete identification of the material tested including the type, source, manufacturers code numbers and history, etc.; d) ambient conditions during the preparation of the specimens and the curi
24、ng regime and conditioning adopted; e) a reference to the procedure used, e.g.“procedure A of BS6319-10”; f) the individual test results and the mean heat distortion temperature under the specified bending stress; g) the nature and initial temperature of the heat transfer medium; h) the mass of each
25、 specimen to the nearest 0.1 g.BS6319-10:1987 2 BSI 08-1999 Appendix A Effect of temperature on resin compositions In contrast to more familiar construction materials such as concrete, steel and wood, the mechanical properties of many thermosetting resin compositions are particularly sensitive to re
26、latively small temperature variations. The effects of temperature may be observed both in the short term, i.e. in minutes, where changes in elastic properties of the material are revealed and, also, over very much longer periods due to variations in the viscoelastic properties of the resin (creep an
27、d stress relaxation phenomena). Subjecting a fully cured thermosetting resin composition to temperature increases will not lead to visible flow of the bulk resin (an effect which is readily observed with many thermoplastic polymers). Nevertheless, for cross-linked resins such as epoxides, polyesters
28、, and polyurethanes, increases in the temperatures of use or testing will generally reduce the elastic modulus and ultimate strength (the converse effects will result from a decrease in temperature). This variation is often quite marked within the temperature range which the resin compositions would
29、 commonly be expected to meet in service, e.g.10 C to50 C. Resin compositions used in construction and repair are generally in intimate contact with a second material, e.g. concrete, steel or wood which normally exhibits a quite different response to temperature variations. Consequently, in addition
30、 to considering the influence of temperature changes on the resin, effects on the performance of the composite have also to be taken into account. The method described in this Part of BS6319 is concerned solely with the short term softening effects of a temperature increase on the cured resin compos
31、ition in isolation from any substrate. Several points concerning the significance of heat distortion temperature (HDT) have to be appreciated. The test conditions and the standard deflection employed in this determination are arbitrary and, in general, will differ from those met in service. Thus, th
32、e data is not intended for direct use in design. The measurement of the heat distortion temperature is useful, however in quality control work, in assessing the degree of cure of thermosetting resins, and also in the development of such compositions. In order to assess the short term performance of
33、resin compositions at elevated temperatures, particularly in structural applications, any determination of the heat distortion temperature should be complemented by information obtained from other appropriate test methods. Use of a suitable combination of test procedures should permit the determinat
34、ion of a temperature limit below which the resin composition will perform satisfactorily in the short term, i.e. rapid, catastrophic failure or unacceptable strain will not occur when a given stress is applied to a heated resin (or heat to a stressed system). The longer term effects of elevated temp
35、eratures on resin compositions may also have to be considered for some applications, particularly those of a structural type. Thus, the upper service temperature limit of a resin composition may be set, for example, not by failure, but by the maximum degree of creep which is permissible. Measurement
36、 of the heat distortion temperatures does not enable predictions to be made in this regard. Appendix B Degree of cure Two following points should be appreciated with regard to the cure state of the resin in relation to measurement of the HDT (or other physical properties). a) High temperature (40 C
37、to50 C), particularly if applied for a period of hours, will often induce further reaction (cross-linking) within the bulk of the solid resin. This post-curing effect will in general increase the HDT as well as the modulus and ultimate strength of the resin. b) Resin compositions mixed and maintaine
38、d at low temperatures (10 C and below) may be incompletely cured yet, if tested at that low temperature, may appear to have satisfactory modulus and strength. If these same specimens are conditioned briefly and tested at the normal laboratory ambient of20 C much lower figures may result, indicating
39、inadequate cure. HDT measurements provide a better means of indicating the state of cure of a resin composition. Incomplete cure will be clearly indicated by a low HDT result relative to a fully cured specimen.BS6319-10:1987 BSI 08-1999 Publications referred to BS 410, Specification for test sieves.
40、 BS 812, Testing aggregates. BS 812-1, Methods for determination of particle size and shape. BS 2782, Methods of testing plastics. BS 2782:Method 121A, Determination of temperature of deflection under a bending stress of1.8MPa of plastics and ebonite 1) . BS 2782:Method 121B, Determination of temper
41、ature of deflection under a bending stress of0.45MPa of plastics and ebonite 1) . BS 6319, Testing of resin compositions for use in construction. BS 6319-1, Method for preparation of test specimens. 1) Included in one publication BS2782:Methods121A to121C.BS 6319-10: 1987 BSI 389 Chiswick High Road
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