MASONRY - Materials for Civil and Construction Engineers - page 313

Sample Problem 8.3

The 5-hour boiling test was performed on a medium weathering clay brick according to
ASTM C67 and produced the following masses:

dry mass of
saturated mass after 5-hour submersion in boiling

specimen = 1.788 kg

water = 2.262 kg

Calculate percent absorption by 5-hour boiling and check whether the brick satisfies
the ASTM requirements.

Solution

2.262 - 1.788
1.788

Absorption by 5 - hour boiling = * 100 = 26.5 %

From Table 8.3, the maximum allowable absorption by 5-hour
. Therefore, the brick does not satisfy the ASTM

boiling = 25.0 %

requirements.

Facing bricks (ASTM C216) are manufactured in two durability grades
for severe weathering (SW) and moderate weathering (MW). Each durability
grade is manufactured in three appearance types: FBS, FBX, and FBA. These
three types stand for face brick standard, face brick extra, and face brick ar-
chitecture. Type FBS bricks are used for general exposed masonry construc-
tion. Type FBX bricks are used for general exterior and interior masonry
construction, where a high degree of precision and a low permissible varia-
tion in size are required. The FBA type bricks are manufactured to produce
characteristic architectural effects resulting from nonuniformity in size and
texture of the individual units.
Similar to concrete masonry units, bricks are designated by their nomi-
nal dimensions. The nominal dimension of the brick is greater than its
specified (or modular ) dimension by the thickness of the mortar joint, which
is about 10 mm (3/8 in.) and could go up to 12.5 mm (1/2 in.). The actual
size of the brick depends on the nominal size and the amount of shrinking
that occurs during the firing process, which ranges from 4% to 15%.
Clay bricks are specified by their nominal width times nominal height
times nominal length. For example, a brick has nominal width
of 100 mm (4 in.), height of 70 mm (2-2/3 in.), and length of 200 mm (8 in.).
Clay bricks are available in nominal widths ranging from 75 mm to 300 mm
(3 in. to 12 in.), heights from 50 mm to 200 mm (2 in. to 8 in.), and lengths
up to 400 mm (16 in.). Bricks can be classified as either modular or non-
modular, where modular bricks have widths and lengths of multiples of
100 mm (4 in.).

4 * 2-2/3 * 8