MSE 220
Chapter 4
Masonry
Problems 2, 3, 4, 5, 7, 8, 11,
12, 17, 18, 19
2.
Two types of masonry units are hollow and solid. Types of masonry units include
brick, tile, stone, glass block and concrete block.
3.
Hollow masonry units have a net cross sectional area in every plane parallel to
load bearing surfaces less than 75% of the gross cross sectional area in the same plane.
Solid units have > 75%.
4.
Raw materials to manufacture brick include burned clay, but may include solid
blocks made of concrete and sand-lime.
5.
Three grades of brick are SW (severe weathering), MW (moderate weathering)
and NW (negligible weathering).
7.
Portland cement is a mixture of limestone and clay, and, after processing, is made
up of dicalcium silicate, tricalcium silicate, tricalcium aluminate and tetracalcium
aluminoferrite.
Masonry cement is similar to Portland cement in that it contains Portland cement,
Portland-pozzolan cement, natural cement, slag cement, Portland blast-furnace slag
cement or hydraulic lime, but may also include hydrated lime, limestone, chalk, shells,
talc, slag or clay.
8.
Adding lime to mortar increases is plasticity, ability to retain moisture and
workability.
11.
Four types of standard mortar are M, S, N and O. Type M has the lowest hydrated
lime content, while O has the highest.
12.
“Flow” is the % increase in diameter of a conical frustrum of mortar 4” in
diameter at its base after the flow table has been dropped through a height of ½” 25 times
in 15 seconds.
17.
Two properties that determine the compressive strength of masonry are the
compressive strength of the units and the mortar mix proportions.
18.
1500 psi. See Figure 4.26.
19.
Efflorescence is the leaching of soluble salts in brick leading to white patches on
the face.