1、STD-BSI BS EN 1170-5-ENGL 1998 1b24bb9 b88919 253 m BRITISH STANDARD Precast concrete products - Test method for glass-fibre reinforced cement Part 5. Measuring bending strength, Complete bending test method The European Standard EN 11705 : 1997 has the status of a British Standard ICs 91.100.30 BS
2、EN 1170-5 : 1998 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STDOBSI BS EN 1170-5-ENGL 1998 M 1b29bbS Ob88720 T75 direction of the Sector Board for Building and Civil Engineering, was pubiished under the authority of the Standards Board and comes into effect on 16 March 19
3、98 Amd. No. Q BSI 1998 BS EN 1170-6 : 1998 Da Textaffected National foreword “his British Stanard is the English language version of EN 1170-5 : 1997 published by the European Committee for Staneon (CEN). The UK participation in its preparation was entrusted to lchnicai Committee B/624, Recast concr
4、ete products, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; - monitor related international and European developments and promu
5、lgate them in the UK. The UK voted against this standard at the CEN Fod Vote stage but the analysis of voting, in accordance with CENKENELEC Internal Regulations Part 2: Common rules for standarcls work resulted in a positive vote. This standard, together with BS EN 1170 : Parts 1 to 4,6 and 7, supe
6、rsedes BS 6432 : 1984 which is withdrawn. A list of organizations represented on this committee can be obtained on request to its secreay. Cross-references The British Standards which implement intemational or European publications referred to in this document may be found in the BSI Standards Catal
7、ogue under the section entitied Intedonai Standards Correspondence Index, or by using the fi8 facility of the BSI Stanclards Eledmnic Catalogue. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an in
8、side hnt cover, the EN title page, pages 2 to 6, an inside back cover and a back cover. ISBN O 680 29202 9 - STD-BSI BS EN 1170-5-ENGL 1778 lb24bb9 Ob88721 901 EUROPEAN sTANDAR(D NORME EUROPENNE EuROP thickness of test piece in miilimetres; load at limit of proportionality, in newtons; failure load,
9、 in newtons; length of test piece, in millimetres; span, in millimetres; mass of test piece after drying, dry mass, in grams; mass of test piece before drymg, wet mass, in grams; water content, in percentage by mass; deflection at limit of proportionality, in millimetres; deflection at failure in mi
10、ilimetres; stress at limit of proportionaliw, deformation at failure stress at limit of proportionalis: in megapascals; stress at failure, in megapascals. Page 3 EN 11705 : 1997 3.2 Abbreviation GRC glassfibre reinforced cement. 4 Apparatus The apparatus comprises : - a bending test mahine, of accur
11、acy meeting the class 2 requirements specified in IS0 7500-1. It is provided with a four-point bending device (minimum diameter of supports: 6 111111) and a displacement sensor (accurate to 0,Ol m) located preferably in the tsansverse axis of symmetry of the test device. The test device shall be fit
12、ted with a system for plotting the loddeflection curve, either on-line or off-line ; - twoJlat, easy to clean, moth material plates, of approximately (500 X 800) mm. In the case of a pouring production, provide for a frame having a thickness equal to that of the product being manufactured - aJlat-bo
13、ttrmzed tunk, of approximately (500 X 200 X 100) mm filled with water maintained at (20f2)“C; - U rule, accurate to 0,5 mm ; - a calliper, accurate to 0,l mm ; - a ventilated drying oven, usted to (105 I 5) “C ; - a scale, with a measuring range O kg to 2 kg accurate to 0,l g. 5 Procedure 6.1 Test p
14、ieces Consecutively make sample panels on the two flat boards, with no facing layer (solid GRC only) under the same conditions as for the actual production they represent: spray or premix. After 24 h, demould and store the two sample panels under the same conditions as for the actuai production they
15、 represent for 6 days. NOTE. The test pieces can also be cut out on the day of demoulding. Cut out by sawing in each panel, at (50 0) mm from the edges, eight test pieces from the positions ilustrated in figure 1. Mark the test pieces as shown in figure 1. Dimensions of the test pieces: - width : (5
16、0 I 2) mm ; - length as a function of the thickness, in accordance with table 1. The variations in thickness of the test pieces shall not exceed 5 % and shall be hited to 0,5 mm. e.g. by grinding NOTE. The thickness of the test piece may need to be changed to meet this requirement O BSI 1998 STD=BSI
17、 BS EN IIII70-5-ENGL II778 D Lb29bb9 Ob88729 bLO D Page 4 EN U706 : 1997 I I Figure 1. Position and identification of test pieces I Jhble 1. Length of test pieces as a function of I their thickness Storage of the test pieces : a) test pieces from the hst panel : When the eight test pieces have been
18、aged for six days, immem them in the tank filled with water at (20 f 2) “C for 24 h so that they have been aged for seven days at the time of the tests ; b) test pieces from the second panel : When the test pieces have been aged for six days, keep them in the laboratory at a temperature of (20 f 3)
19、“C and reiative humiity of (SO f 5) % for 21 days so that they have been aged for 27 days. Then imrnw them in water at (20f2) “C for24h for the test at 28 days. in both cases the test sha,li be ded out no more than i12 h after the test pieces have been removed from the water. After removal from the
20、water and prior to the test, wipe the test pieces with a damp cloth to remove any surface water. 6.2 Test method Measure the length of each test piece to the nearest miimetxe. Position the test pieces in the testing machine, as shown in figure 2, on the two bottom supports with a span L between them
21、 determined in accordance with table 2. For each test panel, the test pieces marked 1 and 3 are tested with the mould face down on the two bottom supports and those marked 2 and 4 with the mould face in contact with the top supports. To start the test, adjust the rate of application of the load : -
22、automatic control by load: (10 f 0,3) N/s ; - automatic control by displacement (0,03 k 0,003) ds. NOTE. in order to evaluate correctly the iimit of proportionality, the load and displacement sensors should be zeroed at the moment the test piece is in contact with the top supports. Continue the test
23、 until complete failure of the test piece. Stop recoring at 0,9 FMOR. Measure the thickness and width of the test piece in the failure zone to the nearest 0,l mm. Weigh each test piece, ie. mw (in grams). After failure, place the test pieces in the ventilated drying oven adjusted to (105 f 5) “C unt
24、il a constant mass md is attained, i.e. until the ifference between two weighing results 24 h apart is less than 0,196 Table 2. Span of test pieces as a function of their length Dimensions in miiiimetres SDan L F Figure 2. Position of test pieces in testing machine Q BSI 1998 Page 5 EN 11705 : 1997
25、6 Expression of results 6.1 Deflection and load at the limit of proportionality The deflection dop and load FLOP at the limit of proportionaiity are assessed by considering the loaddeflection curve. They correspond to the point where the linearity of the two chasacteristics changes. NOTE. To evaluat
26、e the limit of proportionality in the best possible way, it is desirable that the choice of scales on the loaddeflection graph produces a slope of approximately 45 “C. 6.2 Deflection and load on failure The deflection AMOR and load FMOR on failure correspond to the maximum load value recorded. NOTE.
27、 The determination of the ultimate value of the deflection may be difficult. However, examination of the descending section of the curve is important because this gives supplementary information on the ductility of the material. 6.3 Deformation and stress The deflection and the load depend on the ge
28、ometty of the test piece. ln order to compare the mechanical behaviour of the different test pieces it is necessary to express the resuits in form of deflection and sixes (of the extreme fibres of the bottom face). The deformation (wp and EMOR) and stress (CLOP and OMOR) values at the limit of propo
29、rtionality and on failure are given by the following equations : NOTE I. The two equations shown above for calculating and are applicable when the displacement sensor for measuring the deflection is placed in the middle of the axis of symmetry of the test device. if the sensor is placed normal to th
30、e bottom support, he constant 23 should be replaced by 5 in the two equations. NOTE 2. These four equations are only applicable theoretically in the case of linear isotropic elastic materials. However, the values calculated using them are sufficiently approximate for GRC material. NOTE 3. The conver
31、sion formulae are: gMOR (subserviance by moving) = 0,70 u, (subsewiance by loading) + 2,26 oMOR (subserviance by loading) = 1,34 u, (su?, crviance by moving) - 2,22 6.4 Water content The water content is determined by the following equation : 108 27 expressed in percentage by mass, W= - md x 100 md
32、Load t / / / FMOR / . ._._._._ DcWcdion Figure 3. Example of load/deflection curve O BS1 1998 - STDmBSI BS EN II70-5-ENGL I778 = Lb211bb7 Ob8872b 1173 = Page 6 EN il706 : 1997 7 nst report The test report shaU contain the following informa tio - the identification of the laboratory (especially the c
33、haracteristics and accuracy of the test machine, name of the test supervisor); - the complete identification of the test pieces (especiauy their origin, marking, date of manufacture of the panels); - all indMdual results : dimensions, wet mass, dry mass, loads, stress, deflection and deformation at
34、limit of proportionaiity and on failure, water content; - the loddeflection curves; - the mean average values at 7 and 28 days: CLOP EMOR, OMOR and W ; - the relationshitx between the mean sbresses on failure (MOR) ofhe identified test pieces Ti + T2 + T3 + T4 Bi + B3. and Bi+B2+ - the reference to
35、this standard; -the date of test. d BSI 1998 STD*BSI BS EN LL70-5-ENGL 1778 D Lb24bb9 Ob88927 32T D BS EN 1170-5 : 1998 BSI 389ChiswickHighRoad London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view
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