12 Ag Mechanics: Concrete MC

A quart jar with 2' of sand for concrete should not yield more than ____ of silt. a. 1/8" c. 3/16" b. 1/4" d. 1/2"

A

Forms for walks and slabs are usually made from a.2x4 lumber c.2x8 lumber b.2x6 lumber d.concrete blocks

A

Burning limestone and clay, then grinding it finely and mixing to uniformity results in: a. Concrete c. Portland Cement b. Mortar d. Masonry

B

Concrete is reinforced with a.aluminum wire c.gravel b.steel bars d.wood chips

B

Concrete starts to harden in about: a. 5 minutes c. 30 minutes b. 15 minutes d. 1 hour

B

The frost line in NW Arkansas is: a. 6" c. 18" b. 12" d. 24"

B

To prevent concrete from sticking to the forms, treat them with a.fat c. silicone b.oil d. water

B

Which is NOT a factor in the strength and durability of concrete? a.purity of water c.type of cement b.size of the pad d.proportion of aggregate by size

B

A planned break to allow for expansion or contraction of the concrete is called a: a. seam c. control joint b. construction joint d. groove

C

A standard sized concrete block will cover an area that is a. 8" by 12" c. 8" x 16" b. 4" x 8" d. 12' x 20"

C

Courses of block are laid straight by using a a. plumb bob c. line and line level b. square d. ruler

C

The smallest soil particle is a. sand c. clay b. silt d. organic matter

C

What will sabotage the curing process? a.covering with plastic B.protecting from wind C.allowing the concrete to freeze d.sprinkling with water

C

Which is NOT a characteristic of a workable mix? a. all aggregates are clean B. aggregate is completely coated with paste C. dry powder is present d. aggregate is mixed evenly in the mix

C

Which is NOT a type of finish for concrete? a. float c. blowing b. broom d. machine

C

Which is not a recommended reinforcement for concrete? a. air-entraining c. pallets b. wire mesh d. steel rods

C

A concrete slab that is 6" deep by 20' wide by 20' long will require a.88.8 cubic yards c.400 cubic yards b.200 cubic yards d.7.4 cubic yards

D

Concrete is a mixture of sand, gravel, water and a.clay cement c.finishing lime b.finishing cement d.portland cement

D

Mortar is a mixture of portland cement, sand, water and a.aggregate c.finishing cement b.clay d.finishing lime

D

The 1:2:3 method of mixing concrete is in which proportions? a. water, aggregate, portland cement B. portland cement, water, sand C. sand, portland cement, water d. portland cement, sand, aggregate

D