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^aц?io^aё?ь?^и?й? 1 2 3 4 5 O 6 7 8 9 EN 772-19:2000 - - - FOREWORD
This European Standard has been prepared by Technical Committee CEN/TC 125 "Masonry", the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2000, and conflicting national standards shall be withdrawn at the latest by December 2000.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
^AЦ?IO^AЁ?Ь?^И?Й? Methods of test for masonry units -Part 19: Determination of moisture expansion of large horizontally perforated clay masonry units
1 2 EN 771-1 3 1 SCOPE
This European Standard specifies an accelerated method of determining the moisture expansion of large clay units with horizontal perforations that have one dimension equal to or greater than 400 mm and shell thicknesses less than 12 mm.
2 NORMATIVE REFERENCES
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies.
EN 771-1 Specification for masonry units - Part 1: Clay masonry units
3 PRINCIPLE
This test measures the length change of test specimens caused by subjecting them to boiling water for a 24 h period ..
4 l i - R in - l s 1 - l s 2 - l m 1 - l s l s 4 - l m 2 - e s - e m - 4 SYMBOLS
l i is the initial length an individual specimen
after kiln refiring and cooling at ambient temperature, (mm)
R in is the reading from the invar reference bar
using the direct reading gauge, (mm)
ls1 is the first deviation which is the difference
between the first reading from an individual specimen ( R ls2 is the second deviation which is the
difference between the second reading from an individual specimen ( R l m 1 is the mean initial deviation of an indivi
dual specimen, (mm)
ls3 is the third deviation which is the diffe
rence between the third reading from an individual specimen ( R ls4 is the fourth deviation which is the diffe
rence between the fourth reading from an individual specimen ( R l m 2 is the mean final deviation of an individual
specimen, (mm)
e s is the moisture expansion of an individual
specimen, (mm/m)
e m is the mean value of moisture expansion,
(mm/m)
5 O 5.1 5.2 5.3 B 5 APPARATUS
5.1 Reference bars of nickel steel (invar) of the approximate length of the test specimens.
5.2 Kiln capable of maintaining a rate of rise of temperature of approximately 50 5.3 Suitable type of measuring frame fitted with a dial gauge, a transducer or similar device, with an accuracy of at least 0,01 mm, (See example in figure 1)
1 - 2 - 3 - 4 - 5 - Figure 1 - Measuring frame showing measurement of invar reference bar and of specimen
5.4 5.5 5.6 5.7 5.4 Vernier callipers or other suitable apparatus for linear measurement to the nearest 0,1 mm.
5.5 Special measurement reference pads and adhesive, if necessary.
5.6 Apparatus for maintaining the test specimens in boiling water for 24 h.
5.7 Desiccator capable of holding all the specimens.
6 7 7.1 7.2 7.3 7.3.1 7.3.2 6 SAMPLING
The method of sampling shall be in accordance with the relevant part of EN 771-1. The minimum number of specimens shall be six, but a larger minimum number may be specified in the product specification, in which case that larger number shall be used.
7 PROCEDURE
7.1 Preparation
Cut a specimen out of a shell from each masonry unit parallel to the perforations. The length shall be as great as possible between 150 mm to 250 mm, depending on the reference bars (5.1). The minimum width shall be 40 mm. Prepare the ends of the specimens as necessary so that the measuring device bears onto flat surfaces perpendicular to the axis of the specimen.
Note: Special end preparation may have to be carried out on the specimens before being measured, e.g. special adhesive measurement reference pads (5.5) or depressions cut in ends of specimen as appropriate.
7.2 Refiring
If the specimens have been wetted during preparation then store them for 24 h at ambient temperature.
Refire the specimens in a kiln (5.2), maintaining a temperature rise of 50 Allow the specimens to cool inside the kiln. When the temperature has fallen to 70 7.3 Initial measurement
7.3.1 Initial measurement of total length ( l i )
Determine and record the length ( l i ) of each specimen to the nearest 0,1 mm using vernier callipers (5.4) or other suitable apparatus. Choose the invar reference bar accordingly.
7.3.2 Measurement of first and second deviations ( l s 1 and l s 2 ) and mean initial deviations ( l m 1 )
The readings required by this sub-clause are made using the measuring frame (5.3) and to the nearest 0,01 mm.
Take and record the reading of the invar reference bar ( R in ).
Take and record the first reading of each specimen after kiln refiring and cooling to ambient temperature ( R Take and record the second reading of each specimen after kiln refiring, cooling to ambient temperature and subsequent 3 h hold ( R For each specimen, record the initial deviation ( l m 1 ) as the mean of ( l s 1 ) and ( l s 2 ) to the nearest 0,01 mm.
a) case where the invar bar is shorter than the specimen
1 - 2 - 3 - б?) b) case where the invar bar is longer than the specimen
Key:
1 Invar bar
2 Specimen after refiring
3 Specimen after boiling water treatment
7.4 7.5 7.4 Boiling water treatment
Immerse the specimens in boiling water (5.6) for 24 h. The test specimens shall be supported clear of the base of the tank and shall not be in contact with the sides.
Remove the test specimens and allow them to cool at room temperature.
7.5 Measurement of third and fourth deviations ( l s 3 and l s 4 ) and mean final deviations ( l m 2 )
The readings required by this sub clause are made using the measuring frame and to the nearest 0,01 mm.
Take and record the reading of the invar reference bar ( R in ).
Take and record the third reading of each specimen 1 h after cooling following boiling water treatment ( R Take and record the fourth reading of each specimen ( R Calculate and record, for each specimen, the fourth deviation ( l s 4 ), i.e. the difference between R For each specimen, record the final deviation ( l m 2 ) as the mean of ( l s 3 ) and ( l s 4 ) to the nearest 0,01 mm.
8 8 EXPRESSION OF RESULTS For each specimen calculate the moisture expansion due to the boiling water treatment ( e s ) to the nearest 0,1 mm/m as follows; e s
= m2 2 l m 1 X 1000. l i
From the individual values ( e s ) calculate the mean value of the moisture expansion ( e m ) to the nearest 0,1 mm/m.
9 Ї?POTOKOЁ? B ї?poт?oк?oё? а?) b) с?) d) е?) f) g) h) і?) 9 TEST REPORT
The test report shall contain the following information:
a) the number, title and date of issue of this European Standard,
b) the name of the organisation that carried out the sampling and the method used;
c) the date of testing;
d) the type, origin and designation of the masonry unit by reference to EN 771-1;
e) the number of specimens in the sample;
f) the date of delivery of the specimens to the testing laboratory;
g) the moisture expansion e s for each specimen expressed in mm/m, to the nearest 0,1 mm/m;
h) the mean value e m of moisture expansion expressed in mm/m, to the nearest 0,1 mm/m;
i) remarks (if any). **********