1、BRITISH STANDARD BS 6319-11: 1993 Testing of resin and polymer/cement compositions for use in construction Part 11: Methods for determination of creep in compression and in tensionBS6319-11:1993 This British Standard, having been prepared under the direction of the Technical Committee B/517, was pub
2、lished under the authority of the Standards Board and comes into effect on 15 January 1993 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference B/517/8 Draft for comment 89/15229 DC ISBN 0 580 21179 7 Committees responsible for this British Standard The p
3、reparation of this British Standard was entrusted by Technical Committee B/517, Concrete, to Subcommittee B/517/8, Protection and repair of concrete structures, upon which the following bodies were represented: British Adhesives and Sealants Association British Cement Association British Railways Bo
4、ard Building Employers Confederation Cement Admixtures Association Concrete Repair Association Concrete Society County Surveyors Society Department of the Environment (Building Research Establishment) Department of Transport Department of Transport (Transport Research Laboratory) Federation of Civil
5、 Engineering Contractors FeRFA Institution of Highways and Transportation Institution of Structural Engineers Plastics and Rubber Institute Sprayed Concrete Association Amendments issued since publication Amd. No. Date CommentsBS6319-11:1993 BSI 09-1999 i Contents Page Committees responsible Inside
6、front cover Foreword ii 1 Scope 1 2 References 1 3 Definitions 1 4 Principle 1 5 Apparatus 1 6 Test specimens 2 7 Procedure for measuring creep in compression 3 8 Procedure for measuring creep in tension 6 9 Calculation 7 10 Test report 7 Figure 1 Typical hydraulic compressive creep rig 4 Figure 2 T
7、ypical dead weight tensile creep rig 5 Figure 3 End anchorage plates for tensile creep specimens 5 Figure 4 Necked specimens for tensile creep testing 6 List of references Inside back coverBS6319-11:1993 ii BSI 09-1999 Foreword This Part of BS6319 has been prepared under the direction of Technical C
8、ommitteeB/517, Concrete. This Part describes methods for determining creep in compression and in tension and is one of a series of Parts describing methods for measuring basic physical properties of resin and polymer modified materials. This Part of BS6319 should be read in conjunction with BS 6319-
9、1 which provides general information and describes the 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
10、 of itself confer immunity from legal obligations. In particular, attention is drawn to the Health and Safety at Work etc. Act 1974 1. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, an inside back cover and a back cover. This standard has
11、 been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6319-11:1993 BSI 09-1999 1 1 Scope This Part of BS6319 describes methods for the determination of the creep of specimens of polymer and polymer/cemen
12、t mortars. Creep in compression is measured on rectangular prisms and creep in tension on necked specimens having a maximum aggregate size of2.4mm. The prime objective of the methods is to provide comparative data on materials in order to establish whether or not creep is likely to be significant in
13、 the intended application. The methods provide an estimate of creep strains within 10% of the absolute value under the particular environmental conditions in which the test is conducted. For comparative purposes, it is necessary to control the temperature to within 2 C of the specified temperature b
14、ut control of humidity is not essential. NOTEFor specific applications where a higher level of accuracy is required, additional requirements for measurement of load, achieving axiality and environmental conditions should be agreed before testing commences. 2 References 2.1 Normative references This
15、Part of BS6319 incorporates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publication
16、s apply to this Part of BS6319 only when incorporated in it by updating or revision. 2.2 Informative references This Part of BS6319 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside
17、 back cover, but reference should be made to the latest editions. 3 Definitions For the purposes of this Part of BS6319 the definitions given in BS 6319-1:1983 apply, together with the following. 3.1 compressive stress force per unit area of the original cross section of a member in compression 3.2
18、elastic strain deformation produced by a stress up to the elastic limit and expressed as the change per unit of original dimension 3.3 elastic compressive strain elastic strain measured immediately following the application of compressive load 3.4 tensile stress force per unit area of the original c
19、ross section of a member in tension 3.5 elastic tensile strain elastic strain measured immediately following the application of tensile load 3.6 creep strain time-dependent strain measured over and above elastic strain under the application of a constant load 3.7 creep coefficient ratio of creep str
20、ain to elastic strain at the same applied stress 3.8 elastic recovery strain amount of elastic strain lost by a member immediately on unloading to zero stress 3.9 creep recovery strain amount of creep strain lost by a member following unloading to zero stress 3.10 creep recovery coefficient ratio of
21、 creep recovery strain to elastic recovery strain 4 Principle In the test for creep in compression, a prism of 4 : 1 aspect ratio is subjected to a constant compressive load and change in creep strain with time is related to the elastic compressive strain. In the test for creep in tension, a necked
22、specimen is subjected to a constant tensile load and change in creep strain with time is related to the elastic tensile strain. 5 Apparatus 5.1 Compressive creep rig, capable of applying the constant load, derived as in7.2.5, for at least30weeks along the axis of the test specimens described in6.1.B
23、S6319-11:1993 2 BSI 09-1999 NOTEA suitable hydraulic compressive creep rig capable of testing two specimens simultaneously is illustrated inFigure 1. The incorporation of a gas/oil accumulator in the hydraulic system serves to extend the time between occasions when it will be necessary to pump oil i
24、n order to maintain the pressure applied to the flat jack and hence the load applied to the specimen at constant values for the duration of the test. The compressive load and hence the compressive stress applied to the specimens is monitored by a load cell conforming to grade2.0 of BS1610-2:1985 ins
25、erted between the upper specimen and the upper platen of the rig. The rig is capable of applying load at the rate specified in7.2.5 by the use of a needle valve in the hydraulic line upstream of the flat jack. The platens have a stiffness (axial load/central deflection) of not less than 2500kN/mm to
26、 avoid excessive deformation during loadings. The flatness tolerance for the area of the platen in contact with the load cell conforms to clause 5 of BS1881-115:1986. Spacing blocks are used between the specimens and the flat jack to reduce the test space and to compensate for any bow developed in t
27、he faces of the flat jack when under pressure. The spacing blocks are either circular or square in section, enable the specimens to be correctly centered and support them over the whole area of their ends. The properties of the material, the surface flatness, and the surface texture of the contact f
28、aces of all spacing blocks conform to clause 7 of BS1881-115:1986. A spherical seating is incorporated between the load cell and the top end piece of the upper specimen. The vertical pillars connecting the platens of the rig have a stiffness (axial load/axial deflection) of not less than250kN/mm. Th
29、ey incorporate a means of adjustment to provide a parallelism tolerance between the upper and lower platens of0.06mm (see 10.8.4 of BS 308-3:1990). 5.2 Tensile creep rig, capable of applying the constant load, derived as in8.2.5, for at least30weeks along the axis of the test specimens described in6
30、.2. NOTEA suitable dead weight tensile creep rig is illustrated inFigure 2. This comprises a loading frame, a lever system and weights to apply a constant tensile force to three specimens mounted in series. The end and intermediate specimen anchorage units are detailed inFigure 3. They consist of3mm
31、 thick rectangular plates drilled to give a close tolerance fit to16mm diameter anchorage pins. The end anchorage plates are attached to the bottom of the straining frame and to the loading beam at the top through universal anchorage couplings. The anchorage plates are manufactured to the tolerances
32、 specified in3.1.2 of BS 6319-1:1983. 5.3 Moulds, conforming to3.1 of BS 6319-1:1983 and of a size to produce rectangular prisms in accordance with6.1 or necked specimens in accordance with6.2. 5.4 Strain gauges. Two strain gauges shall have a gauge length of100mm and maximum sensitivity204m/m for m
33、easuring compressive strain on each specimen. Eight strain gauges shall have a gauge length of50mm for measuring tensile strain. The strain gauges shall be connected to equipment capable of providing a continuous indication of strain. They shall be calibrated by a method traceable to a national or I
34、nternational Standard of length measurement. In the UK, this is the responsibility of the National Physical Laboratory (NPL). The error shall not exceed2% of the actual strain. 5.5 Environmental chamber (optional), to control the ambient temperature of the tensile creep specimens. It shall be able t
35、o maintain a steady temperature for individual control settings within a range from 25 C to + 50 C to an accuracy of 1 C. It shall be constructed so that only the loading bars at the top and bottom of the line of tensile creep specimens protrude. 5.6 Thermocouple (optional), for measuring the temper
36、ature in the environmental chamber (5.5), capable of measuring to the nearest0.2 C over a range from 25 C to + 50 C. It shall be connected to equipment capable of providing a continuous indication of temperature. 6 Test specimens 6.1 Dimensions of compressive creep test specimens Compressive creep t
37、est specimens shall be rectangular prisms of nominal size40mm 40mm 160mm unless the material contains an aggregate of which at least 90%, when sampled in accordance with BS 812-102:1989, will not pass through a 5mm test sieve conforming to BS410:1986. For such materials the width and depth of the pr
38、isms shall be between 7.0 and 8.0 times the nominal mesh size of the smallest test sieve conforming to BS 410:1986 through which90% of the aggregate will pass. The length to width ratio of the prisms shall be 4 : 1. 6.2 Dimensions of tensile creep test specimens Tensile creep test specimens shall ha
39、ve a necked length of150mm and a cross section of40mm 12mm as shown inFigure 4. The internal radius of the anchorage sections shall be9mm. 6.3 Preparation of test specimens Prepare the test specimens, including the conditioning, proportioning and mixing of the materials and the conditioning and fill
40、ing of the moulds, in accordance with BS 6319-1:1983. Specimens for measuring tensile creep shall not contain aggregate of size greater than2.4mm.BS6319-11:1993 BSI 09-1999 3 7 Procedure for measuring creep in compression 7.1 Number of specimens Test a minimium of two specimens at a time cast from o
41、ne batch of material for each prescribed set of test conditions. Use a further specimen from the same batch as a control specimen. 7.2 Testing 7.2.1 Temperature Carry out the test at (23 2) C unless, for a specific purpose, an alternative temperature has been agreed. Maintain the test specimens at t
42、he test temperature for not less than16h before testing commences. 7.2.2 Age at loading Commence the test when the test specimens have attained an age of 28 days unless, for a specific purpose, an alternative age has been agreed. 7.2.3 Measurement Measure the width and thickness of each specimen at
43、its centre to the nearest0.1mm and calculate its cross-sectional area. 7.2.4 Placing the test specimen in the creep rig Fit two strain gauges (5.4) to opposite cast sides of the test and control specimens, their gauge lengths being centrally located over the axis of the test specimens. NOTEBS 1881-2
44、06 gives guidance on the use of strain gauges. Wipe clean the bearing surfaces of the creep rig (5.1) and any spacing blocks. Remove any loose grit or other material from the ends of the test specimens that are to be loaded. Place the test specimens in the rig in such a manner that the load is appli
45、ed axially, i.e. parallel to the long axis of the specimens, and centre it carefully as described in7.2.5. Do not use packing at any of the interfaces between the test specimen, spacing blocks, load cell and platens. 7.2.5 Loading Apply the load smoothly at a rate between 200N/s and 1000N/s until th
46、e specified load P 1for the creep test is indicated. The load P 1shall be one-quarter of that necessary to cause failure in a test to measure compressive strength carried out in accordance with BS 6319-2:1983. In the absence of such information the maximum load P 1to be applied should be that necess
47、ary to cause a compressive strain of 0.002m/m unless, for a specific purpose, an alternative load has been agreed. Smoothly reduce the load to 0.1 P 1and re-apply the load at least twice to ensure that the specimens and platen are well seated and that the strain gauges are indicating consistently. I
48、f the individual strains are not within a range of 10% of their mean value at load P 1 , centre the test specimen again and repeat the procedure. If it is not possible to reduce the difference to within this range do not proceed with the test on that specimen. Select another specimen from the same b
49、atch and continue until two acceptable specimens have been found. Next, zero the strain gauges at zero load, re-apply the load P 1smoothly, maintain the load and immediately take a reading from both strain gauges. Whilst maintaining the load constant at load P 1take readings from both strain gauges at15min intervals for the first hour, at hourly intervals for the next11h, four hourly intervals for the next 12h, daily intervals for the next 6 days and thereafter twice weekly until the termination of the creep phase of the test. Check r
