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Specification 12 Hot Rolled Asphalt and Macadam Appendix A – Use of Magnesium Sulfate Test
for Airfields with Non-Standard Aggregate Fractions
Appendix A – Use of Magnesium Sulfate Test with Non-Standard
Aggregate Fractions
A.1 SCOPE
This Appendix specifies a procedure extending the
method in BS EN 1367-2 for assessing how an
aggregate behaves when subjected to the cyclic
action of immersion in magnesium sulfate, followed
by oven drying, to all fractions.
A.2 APPARATUS AND REAGENTS
Apparatus and reagents as detailed in
BS EN 1367-2, Clauses 7 and 8, (except that the
balance for coarse aggregate, sub-Clause 6.2, to be
accurate to 1 g) together with:
• 20 mm and 6.3 mm sized square hole perforated
plate test sieves and 2 mm, 1 mm, 0.5 mm and
0.25 mm sized woven wire test sieves; the
additional test sieves shall comply with
BS EN 933-2; and
• at least two brass or stainless steel mesh
baskets for immersing aggregate specimens for
fractions other than 10 to 14 mm with the
maximum dimension of the apertures not more
than half the maximum aperture of the sieve on
which the specimen is retained, but not less than
0.125 mm.
A.3 PREPARATION OF TEST PORTIONS
A.3.1 Bulk samples from each nominal size of
aggregate being delivered from each source of
supply to be used shall be tested separately and the
procedure described hereafter shall be applied to
each separate sample.
A.3.2 Prepare two test portions from the bulk
samples of each aggregate supplied as in
BS EN 1367-2, Clauses 8.1 and 8.2, replacing
“minimum mass of 500 g of the 10 mm to 14 mm
size” in Clause 8.1 by the relevant masses from
Table A.1.
A.4 PREPARATION OF AGGREGATE
TEST SPECIMENS FOR EACH
FRACTION
A.4.1 The grading of the test portion shall be
determined by the dry sieving method described in
Clause 8.3 of BS EN 1367-2 using the 20 mm,
10 mm, 6.3 mm, 2 mm, 1 mm, 0.5 mm and 0.25 mm
sieves. For coarse aggregate test specimens, the
fractions retained on the 20 mm sieve and passing
the 1 mm sieve shall be discarded and not taken
into account in the calculation of the test result. The
remainder of the reduced sample shall be
considered as the test portion. The grading shall be
recorded giving the percentage of the mass of the
test portion retained between each pair of sieves,
together with that passing the 0.25 mm sieve for
fine aggregate test specimens, to the nearest whole
number.
A.4.2 Those fractions retained whose proportions
are less than 5 % by mass of the test portion shall
be discarded. Nevertheless, the proportions that
the discarded fractions represent shall be taken into
account in the calculation of the test result.
A.4.3 One test specimen, of mass in accordance
with Table A.1, shall be taken out of each fraction
retained after completion of sub-Clause A.4.2. If
there is insufficient material in any of these fractions
to provide a test specimen of the required size, the
procedure shall be repeated starting from sub-
Clause A.3.2. The grading recorded shall be that
obtained from all the material sieved out.
TABLE A.1 REQUIRED MASS OF COARSE
AGGREGATE TEST SPECIMENS
Sieves Mass of specimen
Passing Retained before test (g)
20 mm 10 mm 1000 ± 10
10 mm 6.3 mm 300 +10 / –0
6.3 mm 2 mm 100 +10 / –0
2 mm 1 mm 100 +10 / –0
38 July 2010