Building Design and Construction Handbook - Merritt - Ventech!

WALL, FLOOR, AND CEILING SYSTEMS 11.7
Brick,’’ C216. Bricks that do not comply with these tolerance requirements may be
used if the ultimate compressive strength of the masonry is determined by prism
tests.
Mortar. Most of the test data on which allowable stresses for engineered brick
masonry are based were obtained for specimens built with portland cement-hydrated
lime mortars. Three mortar types are provided for: M, S, and N, as described in
ASTM C270 (see Art. 4.16), except that the mortar must consist of mixtures of
portland cement (type I, II, or III), hydrated lime (type S, non-air-entrained), and
aggregate when the allowable stresses specified in ‘‘Building Code Requirements
for Engineered Brick Masonry’’ are used. This standard provides, however, that
‘‘Other mortars . . . may be used when approved by the Building Official, provided
strengths for such masonry construction are established by tests . . ’’.
For ordinary unit masonry, mortar should meet the requirements of ASTM C270
and C476. These define the types of mortar described in Art. 4.16. Each type is
used for a specific purpose, as indicated in Table 11.1, based on compressive
strength. However, it should not be assumed that higher-strength mortars are preferable
to lower-strength mortars where lower strength is permitted for particular
uses. The primary purpose of mortar is to bond masonry units together.
Mortars containing lime are generally preferred because of greater workability.
Commonly used:
TABLE 11.1 Mortar Requirements of Masonry
Kind of masonry Types of mortar
Masonry in contact with earth:
Footings M or S
Walls of solid units M, S, or N
Walls of hollow units M or S
Hollow walls
Masonry above grade or interior:
M or S
Piers of solid masonry M, S, or N
Piers of hollow units M or S
Walls of solid masonry M, S, N, or O
Grouted masonry PL or PM
Walls of hollow units; load-bearing or exterior, and M, S, or N
hollow walls 12 in or more in thickness
Hollow walls less than 12 in in thickness where
assumed design wind pressure:
a. Exceeds 20 psf M or S
b. Does not exceed 20 psf M, S, or N
Glass-block masonry M, S, or N
Nonbearing partitions of fireproofing composed of M, S, N, O, or gypsum
structural clay tile or concrete masonry units
Gypsum partition tile or block Gypsum
Firebrick Refractory air-setting mortar
Linings of existing masonry M or S
Masonry other than above M, S, or N