8. Procedure for Mixing Mortars and Concrete 8.1 If the mortar or concrete to be tested is made in
accordance with requirements other than those given in one of
the following paragraphs, samples shall be taken and speci-
mens molded as described in the sections on sampling and on
8.2 Bring all materials to a temperature between 65 and 75
°F [18 and 24 °C] before using to make mortar or concrete.
Proportion solid materials by mass (that is, not by volume). It
is permissible to batch water and liquid admixtures either by
mass or by volume. For calculation of batch quantities, assume
aggregates to be saturated and surface-dry; if they are not in
this condition at the time of use, apply appropriate corrections,
as necessary, to batch quantities to compensate for absorption
or free moisture.
8.3 Mortar—Mix mortar in a mechanical mixer as de-
scribed in Practice
. The clearances between paddle and
bowl specified in Practice
are suitable only for mortars
made with fine aggregates that are finer than the 2.36 mm (No.
8) sieve. Mortars made with aggregates containing particles
coarser than this sieve require special clearances or a different
type of paddle to permit the mixer to operate freely and to
avoid damage to the paddle and bowl. The sequence of mixing
shall be in accordance with the applicable provisions of
. Determine the flow of the mortar in accordance
with the applicable provisions of Test Method C 1437, and use
sufficient mixing water to produce a flow of 110 6 5 %.
8.4 Concrete—Mix concrete in a suitable laboratory mixer
in accordance with the applicable provisions of Practice
C 192/C 192M
. Determine the slump of the concrete using Test
C 143/C 143M
, and use sufficient mixing water to
produce a slump of 3.5 6
in. [90 6 15 mm].