CE MATERIAL Exam 2: HW 11-12
What are the difference among boards, dimension lumber, and timber?
- Boards 1", 1 1/2" thick, 2" and wider is graded according to the same characteristics and manufacturing imperfection as boards - Dimension lumber 2" to 4" thick, 2" wider is graded according to the same characteristics and manufacturing imperfection as boards. - Timbers 5" and thicker, 5"m and wider are graded as beams and stringers or as posts and timbers and are assigned use values as columns or beams.
Describe the manufacturing system most commonly used to manufacture clay masonry?
- In this method, once the clays to be used are blended, crushed and screened, water equal in weight to 10-15 percent of the clay is added to the clay. - The clay is placed in a vacuum to reduce the air content - Clay is shaped by running it through a die and cut to length - Bricks are then dried
What factors influence the compressive strength of concrete masonry units? (8)
- Type of aggregate - Gradation of aggregate - Type of cement - Amount of cement - Consolidation during molding - Method of curing - Shape and size of unit - Condition at time of testing
What three clays are used to manufacture clay masonry?
- surface clays - shales - fire clays
What is the difference between solid and hollow core masonry units?
A masonry unit is hollow cored if the cores exceed 25% of the cross-sectional area of the entire unit.
The strength of a given piece of wood increases as the moisture content ___________.
Decreases
What are the three methods of seasoning wood?
Exposure to the air, exposure to a warm, damp atmosphere in a kiln, coating with a hygroscopic chemical before final drying in air, in a kiln, or in a solution of chemical
Describe grout and how it is used in concrete masonry construction
Grout is a very thin or fluid mixture of water, cement and fine aggregate. It is placed in the void of masonry units to increase their load capacity.
What functions does mortar serve in masonry construction?
Mortar binds masonry units together, seals the spacer between units and compensates for irregularities in size and shape of the units. It is also how the masonry wall unit is bound to the wall tier behind it
Describe the procedures for field-testing clay brick suction rates
One procedure for testing suction rates involves only placing a few drops of water on a brick and checking to see how long it takes to be absorbed.
What materials are used in the manufacture of concrete masonry units?
Portland cement, water, aggregates and sometimes admixtures are the materials used to make concrete masonry units.
What is the main advantage of autoclaved concrete masonry units?
The main advantage of using the autoclave is less shrinkage
What factors influence the compressive strength of clay? (3)
The type of clay, the process used and the degree of burning all affect the compressive strength of clay masonry
What are the moisture content values used to define greenwood and dry wood? Why is this an important distinction? Table G
The upper limit on moisture content is set at 19%. If the wood used is at a higher moisture content then we use factors must be applied.
How do preservatives protect wood from rotting, insects, and marine borers?
They poison the organisms that consume wood
Quantities of lumber are measured and sold by the foot board measure (fbm). Give the fbm quantities of wood: a. 800 lineal ft of 3/4 X 8 " b. 15 pieces of 2 X 4 from 12 ft 0 inches to 12 ft to 12 ft 11 inches in length c. one post 10 ft long, 14 X 14 inches in cross section
a. 800 x 1 x x 8/12 = 533 FBM b. 15 x 12 x 2 x 4/12 = 120 FBM c. 10 x 14 x 14/12 = 163 FBM
When all other factors of compressive strength ________ the stiff mud process produces masonry units of higher strength than other methods.
equal
The more burning produces higher __________________
higher strength
Describe equilibrium moisture content
is the percentage by weight of moisture in the wood to the oven-dry wood that wood eventually reaches when it loses enough moisture to be at equilibrium with the surrounding atmosphere
- The _________ - ________ is the most common for manufacturing clay masonry.
stiff-mud
