and N mortars will be as shown below.
Mortar coloring may be specified as required by
architectural design.
Low alkali cement should be specified for use in
mortar if efflorescence caused by the use of
available cement is a problem.
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Type M mortar shall conform to ASTM C 270 and shall be used for foundation
walls [, basement walls,] [and piers]. Mortar Type [S] [N] shall conform
to the proportion specification of ASTM C 270 except Type S cement-lime
mortar proportions shall be 1 part cement, 1/2 part lime and 4-1/2 parts
aggregate; Type N cement-lime mortar proportions shall be 1 part cement, 1
part lime and 6 parts aggregate. Type N or S mortar shall be used for
non-load-bearing, non-shear-wall interior masonry; [approved commercial
fire clay mortar or refractory cement (calcium-aluminate) mortar for fire
brick and flue liners;] and Type S for remaining masonry work; except where
higher compressive strength is indicated on structural drawings. When
masonry cement ASTM C 91 is used the maximum air content shall be limited
to 12 percent and performance equal to cement-lime mortar shall be
verified. Verification of masonry cement performance shall be based on
ASTM C 780 and ASTM C 1072. Pointing mortar in showers and kitchens shall
contain ammonium stearate, or aluminum tri-stearate, or calcium stearate in
an amount equal to 3 percent by weight of cement used. Cement shall have a
low alkali content and be of one brand. Aggregates shall be from one
source.
2.8.1
Admixtures for Masonry Mortar
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NOTE: Admixtures may cause efflorescence and may
adversely affect the strength of the mix or the
protection of embedded steel items.
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In cold weather, a non-chloride based accelerating admixture may be used
subject to approval. Accelerating admixture shall be non-corrosive, shall
contain less than 0.2 percent chlorides, and shall conform to ASTM C 494/C
494M, Type C.
2.8.2
Colored Mortar
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NOTE: Indicate on the drawings locations of colored
mortar.
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Mortar coloring shall be added to the mortar used for exposed masonry
surfaces to produce a uniform color matching [_____]. Quantity of pigment
to cementitious content of the masonry cement shall not exceed [5] [_____]
by weight; carbon black shall not exceed [1] [_____] percent by weight.
Quantity of pigment to cementitious content of cement-lime mix shall not
exceed [10] [_____] percent by weight, carbon black no more than [2]
[_____] percent by weight. Mortar coloring shall be chemically inert, of
finely ground limeproof pigment, and furnished in accurately pre-measured
and packaged units that can be added to a measured amount of cement.
Compressive strength of colored mortar shall equal [_____].
SECTION 04200
Page 27
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