Question

1. What is the name of the stage of "being less than potential absorption"?

   	a.	Saturated Surface Dry
   	b.	Air dry
   	c.	Oven dry
   	d.	Damp

1 points   

QUESTION 2

1. Fine aggregates are particles that . . .

   	a.	are all of these items
   	b.	completely pass through a 3/8 inch (9.5 mm) sieve.
   	c.	are created from crushing stone.
   	d.	are made of natural sands.

1 points   

QUESTION 3

1. The amount of Fine Aggregate passing the #50 and the #100 sieves will affect . . .

   	a.	strength of the concrete
   	b.	workability and bleeding of the concrete
   	c.	the durability of the concrete.
   	d.	color of the concrete

1 points   

QUESTION 4

1. New concrete made from recycled aggregate, as compared to conventional aggregate, has all of the following properties except . . .

   	a.	some reduction in compressive strength using recycled fine aggregates only.
   	b.	dry shrinkage and creep of the concrete up to 100% lower.
   	c.	equal or better freeze-thaw resistance.
   	d.	good durability.

1 points   

QUESTION 5

1. Care in selecting gap-graded aggregates is not affected by . . .

   	a.	the cost of processing the material is much less than in regularly graded aggregate.
   	b.	excess fine particle sizes may have a higher water demand.
   	c.	homogenizing or segregation may be a problem.
   	d.	certain particle sizes are intentionally omitted.

1 points   

QUESTION 6

1. Aggregates used to produce insulating light-weight concrete (15 - 90 lb/cubic foot) include . . .

   	a.	sand, gravels, crushed stone, and air-cooled blast furnace slags.
   	b.	expanded shale, clay, and slates.
   	c.	barite, limonite, magnetite, ilmenite, hematite, iron and steel punchings or shot.
   	d.	pumice, scoria, vermiculite, and diatomite.

1 points   

QUESTION 7

1. A factor that does not increase acid or corrosive resistance of a fresh mixed concrete is . . .

   	a.	a low permeability.
   	b.	a low-to-moderate cement content.
   	c.	a low water-cement ratio.
   	d.	a protective coating.

1 points   

QUESTION 8

1. Natural aggregates are . . .

   	a.	dug or dredged from a pit, river, lake or seabed.
   	b.	created by screening and washing large quantities of mined material for needed sizes.
   	c.	created by crushing large rock, boulders or cobbles
   	d.	created by crushing recycled pavements and other concrete materials.

1 points   

QUESTION 9

1. The larger the value of the fineness modulus, the . . .

   	a.	ratio has nothing to do with aggregate size.
   	b.	finer the aggregate size.
   	c.	ratio must be a value less than 2.3 for best concrete results.
   	d.	coarser the aggregate size.

1 points   

QUESTION 10

1. Aggregates used to produce fresh-mixed normal-weight concrete (140 - 150 lb/cubic foot) include . . .

   	a.	sand, gravels, crushed stone, and air-cooled blast furnace slags.
   	b.	expanded shale, clay, and slates.
   	c.	barite, limonite, magnetite, ilmenite, hematite, iron and steel punchings or shot.
   	d.	pumice, scoria, vermiculite, and diatomite.

Answer 1

Question 1

Answer (B)

Explanation:

Oven-dry (OD): All moisture is removed from the aggregate by heating in an oven at 105 C to constant weight (overnight heating usually is sufficient). All pores are empty.

Air-dry (AD): All moisture removed from surface, but internal pores partially full.

Saturated-surface-dry (SSD): All pores filled with water, but no film of water on the surface.

Wet: All pores completely filled with water with a film on the surface.

Damp: when moisture diffused through the air or a solid substance or condensed on a surface(adsorption phenomenon) typically with detrimental or unpleasant effects.

Hence Air dry is the condition when internal pores partially full hence absorption is less than potential absorption. Option (B) is the correct answer.

Question 2

Answer (A)

Explanation:

Fine aggregates are usually sand or crushed stone that are less than 9.55mm (3/8inch) in diameter.

Question 3

Answer (B)

Explanation:

The amounts of fine aggregate passing the 300 µm (No. 50) and 150, µm (No. 100) sieves affect workability, surface texture, air content, and bleeding of concrete.

Question 4

Answer (A)

Explanation:

Compressive strength of recycled aggregate is less than natural aggregate. Bulk densities of recycled aggregate are lower than natural aggregate, while the moisture content and water absorption of recycled aggregate mixes are higher than those of natural aggregate.

We are instructed to solve first 4 question at a time and I have done same. However if you have requirement of answer for any specific question please ask in comment.