1 2 4 CONTENTS
page 1 2 З? 4 5 6 7 8 9 10 1 Scope 1
2 Normative references 1
3 Terms and definitions 2
4 Principle 2
5 Apparatus 3
6 Sampling 4
7 Test specimens 4
8 Procedure 5
9 Determination of the percentage
mass loss 7
10 Test report 7
Annex A (informative) Precision 8
Annex Determination of the strength loss after freeze-thaw cycling 9
Bibliography 10 EN 1367-1:2007 - - - -
TESTS FOR THERMALANDWEATHERING PROPERTIES OF AGGREGATESPart 1: Determination of resistance to freezing and thawing
1 2 EN 932-1 EN 932-2 EN 932-5 1 SCOPE
This European Standard specifies a test method which provides information on how an aggregate behaves when it is subjected to the cyclic action of freezing and thawing.
NOTE The stresses on aggregates due to frost depend, amongst other factors, on the degree of water saturation as well as the rate of cooling.
The results provide a means for assessing an aggregate's resistance to this form of weathering.
The test is applicable to aggregates having a particle size between 4 mm and 63 mm.
2 NORMATIVE REFERENCES
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 932-1, Tests for general properties of aggregates - Part 1: Methods for sampling
EN 932-2, Tests for general properties of aggregates - Part 2: Methods for reducing laboratory samples
EN 932-5, Tests for general properties of aggregates - Part 5: Common equipment and calibration
EN 933-2 EN 1097-2 3.1 3.2 3.3 4 EN 933-2, Tests for geometrical properties of aggregates - Part 2: Determination of particle size distribution - Test sieves, nominal size of apertures
EN 1097-2, Tests for mechanical and physical properties of aggregates - Part 2: Methods for the determination of resistance to fragmentation
3 TERMS AND DEFINITIONS
For the purposes of this document, the following terms and definitions apply.
3.1 test specimen
sample used in a single determination when a test method requires more than one determination of a property
3.2 laboratory sample
reduced sample derived from a bulk sample for laboratory testing
3.3 constant mass
successive weightings after drying at least 1 h apart not differing by more than 0,1 %.
NOTE In many cases constant mass can be achieved after a test portion has been dried for a pre-determined period in a specified oven at (110 4 PRINCIPLE
Test portions of single sized aggregates, having been soaked in water at atmospheric pressure, are subjected to 10 freeze-thaw cycles. This involves cooling to -17,5 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 The test method consists of soaking at atmospheric pressure and storage in water for thorough water absorption (see 8.1) and exposure to frost action under water (see 8.2).
5 APPARATUS
5.1 All apparatus, unless otherwise stated, shall conform to the general requirements of EN 932-5.
5.2 Ventilated drying oven, with forced circulation of adequate capacity. The oven shall be capable of being controlled at (110 5.3 Balance, with an accuracy of 5.4 Low temperature cabinet, (upright or chest) with air circulation. The cabinet shall be automatically controlled to adhere to the temperature curve shown in Figure 1. The sample temperature in the thawing out phase can be controlled either by air circulation or immersion of sample cans in a 20 NOTE To achieve a uniform, reproducible cycle alternating freezing and thawing refrigerator cabinet shall be equipped with control device that allows you to install and maintain the cooling process in accordance with 7.2 (temperature and time regimes). If you have a refrigerator cabinet unit to adjust the thawing allowed it to carry out the process of thawing dimensional samples.
5.5 Cans, made from seamless drawn or welded corrosion-resistant sheet metal, with a thickness of about 0,6 mm, having a nominal capacity of 2 000 ml, an internal diameter of 120 mm to 140 mm, and an internal height of 170 mm to 220 mm are suitable. Cans shall be covered by suitable lids.
For lightweight aggregates, cans shall be suitably ballasted.
5.6 Test sieves, conforming to EN 933-2.
5.7 Water, distilled or de-ionised.
1 - 2 - З? - X - Y - Figure 1 - Temperature curve in the centre of the filled can (reference measuring point)located in the middle of the cabinet
6 7 7.1 6 SAMPLING
Sampling shall be carried out in accordance with EN 932-1.
7 TEST SPECIMENS
7.1 General
Three individual test specimens shall be used. The test specimens shall be obtained in accordance with EN 932-2 by sample reduction from aggregates from which oversized and undersized fractions have been removed.
NOTE If it is intended to carry out a strength test after the freeze-thaw cyclic loading, this test should be performed on an appropriate grading sieved out from the laboratory sample, in accordance with Annex B.
7.2 7.2 Size of test specimens
The preferred size fraction shall be within the range 8 mm to 16 mm, but if required, any of the sizes listed in Table 1 may be used.
The quantities for each of the three individual test portions are specified in Table 1, and deviations of Table 1 - Mass of test portions required for the freeze-thaw cyclic test
7.3 - - 8 8.1 7.3 Preparation of test specimens
The tests pecimens shall be washed and adherent particles removed. They shall be dried to constant mass at (110 For lightweight aggregates, dry to constant mass.
Weighing shall be carried out to the following accuracies:
- aggregates up to 16 mm size, to - aggregates above 16 mm size, to 8 PROCEDURE
8.1 Soaking
The test specimens prepared in accordance with 7.3 shall be stored at atmospheric pressure for (24
8.2 а?) Ь?) d) е?) 8.2 Exposure to freezing underwater
Check that the water level in each can is still at least 10 mm above the top of the test specimen and place the lids on the cans. Place the covered cans containing the test specimens in the cabinet, ensuring that the distance between the cans and the sidewalls of the cabinet is not less than 50 mm and the cans are not touching, in order that the heat is extracted from them as uniformly as possible from all sides.
Using the temperature at the centre of a covered can, situated in the centre of the cooled area, as the reference measuring point of temperature, regulate the cabinet so that the temperature follows a cooling curve inside the limits as shown in Figure 1. Subject the samples in the cabinet to a series of 10 freeze-thaw cycles as follows:
a) reduce the temperature from (20 b) reduce the temperature from (0 to -1) NOTE If it is necessary to interrupt the test during the freezing cycle or when under manual control, for example at weekends, the cans should be kept at (-17,5 c) at no stage allow the air temperature to fall below -22 d) after the completion of each freezing cycle thaw the cans by immersion in water at approximately 20 e) after the completion of each thawing phase hold the cans in water at (20 On completion of the tenth cycle, pour the contents of each can into a test sieve having an aperture size that is half the lower size sieve used to prepare the test specimen (e.g. in the case of the 8 mm to 16 mm fraction, into a test sieve of 4 mm aperture size). Wash and sieve the test specimen on the specified sieve by hand. Dry the residue
9 - 10 а?) Ь?) с?) Annex PRECISION
The following precision data was determined from a cross testing experiment carried out under the CEC DG XII Measurement and Testing Programme (Contract №? MAT1-CT 93-0400 Project №? 134 Testing of Industrial Products - Aggregates for Construction) in 1996/1997. 12 laboratories from 8 European countries participated in the cross testing experiment.
The repeatability and reproducibility Ry for a homogeneous material for a size fraction 8 mm to 16 mm (passing a 4 mm test sieve) was as follows: W c = 0,03 + 0,39 X;
Ry = 0,07 + 062 X.
Annex DETERMINATION OF THE STRENGTHLOSS AFTER FREEZE-THAW CYCLING
If it is intended to carry out a strength test after the freeze-thaw cycling loading, this test should be performed on an appropriate grading sieved out from the laboratory sample, in accordance with EN 1097-2.
A laboratory sample should be taken of twice the mass required for the strength test (see Table 1), plus an allowance for waste. This laboratory sample should then be split into two approximately equal parts. The first part should be used for fragmentation and density tests, without being subjected to the freeze thaw cycling, and the second part should be subjected to the freeze-thaw cyclic test.
Calculate the difference in percentage between the strength test results of the test portions, with and without freeze-thaw cycling, following the procedures specified in EN 1097-2.
Calculate the percentage strength loss, accurate to 0,1 %, in accordance with either Equation (2) or Equation (3) as follows:
^ 'LAO
AS la - S M0 - S M1 - AS sz - S szo - S sz1 - where;
AS la is the percentage strength loss;
S M0 is the Los Angeles coefficient of the test portion without freeze-thaw cycling;
S M1 is the Los Angeles coefficient of the test portion after freeze-thaw cycling.
(3)
where;
AS sz is the percentage strength loss;
S szo is the impact value of the test portion without freeze-thaw cycling;
S sz1 is the impact value of the test portion after freeze-thaw cycling.
[1] ISO 5725:1986 1 ) BIBLIOGRAPHY
[1] ISO 5725:1986 1 Precision of test methods - Determination of repeatability and reproducibility for a stand and test method by inter-laboratory tests
T Withdrawn