CPII Materials & Testing 5

Question 1

What does 'specific gravity' of an aggregate indicate to an inspector?

Accepted Answer

The ratio of aggregate density to the density of water, used in mix design calculations

Answer

Specific gravity is the ratio of aggregate mass to the mass of an equal volume of water and is used to calculate volumes in concrete and asphalt mix designs.

Question 2

Which type of pipe joint is most commonly used for ductile iron water main installations to allow slight angular deflection?

Accepted Answer

Push-on (bell and spigot) joint with elastomeric gasket

Answer

Push-on joints with rubber gaskets provide a watertight seal while allowing small angular deflections to accommodate ground movement and alignment changes.

Question 3

What does 'aggregate absorption' measure, and why is it important for concrete mix design?

Accepted Answer

The percentage of water aggregate can absorb into its pores, affecting effective water-cement ratio

Answer

Absorption capacity determines how much water aggregate will draw from the mix, so it must be accounted for to maintain the target water-cement ratio.

Question 4

During pile driving inspection, what does the pile driving analyzer (PDA) measure?

Accepted Answer

Force and velocity waves during driving to estimate capacity, stress, and hammer energy

Answer

The PDA uses sensors attached to the pile to record stress wave data during each hammer blow, allowing estimation of pile capacity and integrity.

Question 5

What is the purpose of a pentrometer test in soil inspection?

Accepted Answer

Quickly estimate in-place shear strength or consistency of cohesive soils

Answer

A pocket penetrometer provides a rapid estimate of unconfined compressive strength of cohesive (clay) soils at the point of testing.

(CPII) Certified Public Infrastructure Inspector Practice Test

(CPII) Certified Public Infrastructure Inspector Practice Test

CPII Materials & Testing 5