ASTM C 270 TABLE 2 Property Specification Requirements
(For laboratory prepared mortar only)
Mortar
Type
Average
Water
Air
Aggregate
Compressive
Retention
Content
Ratio
Strength
Min.
Max.
(Measured
at 28 Days
Percent
Percent
in Damp,
Loose
Min. MPa
Condition)
O
2
75
14*
3 1/2 times
the sum of
the
Masonry cement
M
17
75
**
separate
S
12
75
**
volumes of
N
5
75
**
cementitious
O
2
75
**
materials
*
When structural reinforcement is incorporated in cement-lime
mortar, the maximum air content shall be 12 percent.
**
When structural reinforcement is incorporated in masonry
cement mortar, the maximum air content shall be 18 percent.
Type N should be used only for non-load-bearing walls.
Approximate the f'm of the unit masonry. Mortars should
be slightly weaker than masonry units so that cracking
will occur in joints where easy to repair.
ASTM C 270 TABLE 2 Property Specification Requirements
(For laboratory prepared mortar only)
Mortar
Type
Average
Water
Air
Aggregate
Compressive
Retention
Content
Ratio
Strength
Min.
Max.
(Measured in
at 28 Days
Percent
Percent
in Damp,
Loose
Min. psi
Condition)
Cement-lime
M
2500
75
12
Not less
than
S
1800
75
12
2 1/4 and
N
750
75
14*
not more
than
O
350
75
14*
3 1/2 times
the sum of
the
Masonry cement
M
2500
75
**
separate
S
1800
75
**
volumes of
N
750
75
**
cementitious
O
350
75
**
materials
*
When structural reinforcement is incorporated in cement-lime
mortar, the maximum air content shall be 12 percent.
**
When structural reinforcement is incorporated in masonry
cement mortar, the maximum air content shall be 18 percent.
Type N should be used only for non-load-bearing walls.
SECTION 04200
Page 25
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