CFB Quality Control & Inspection 3

Question 1

Which non-destructive testing method uses high-frequency sound waves to detect internal flaws in structural steel welds?

Accepted Answer

Ultrasonic testing (UT)

Answer

Ultrasonic testing (UT) transmits sound waves through material and detects internal discontinuities by analyzing reflected signals, making it ideal for subsurface weld defects.

Question 2

What is the minimum curing period for normal-weight concrete flatwork to achieve adequate strength gain before removing forms, according to ACI 308?

Accepted Answer

7 days minimum for most applications

Answer

ACI 308 recommends a minimum 7-day moist curing period for most concrete flatwork using Type I/II cement to ensure adequate early-age strength development.

Question 3

During roofing installation, a field inspector observes that membrane laps are only 2 inches wide instead of the specified 3 inches. This deficiency primarily risks:

Accepted Answer

Water infiltration at the seam under wind-driven rain

Answer

Insufficient lap width reduces the seam bond length, making it prone to separation and allowing water to infiltrate the building envelope during rain events.

Question 4

A field builder reviewing reinforcing steel placement finds the bottom mat in a slab has 3/4-inch cover instead of the specified 1.5-inch clear cover. The BEST course of action is:

Accepted Answer

Reject and require repositioning to meet specification before concrete placement

Answer

Insufficient cover reduces corrosion protection and fire resistance; reinforcing must be repositioned to meet the specified cover before concrete is placed.

Question 5

What does a pull-out test on a post-installed anchor evaluate?

Accepted Answer

The installed anchor's load capacity in tension within the base material

Answer

A pull-out test applies a measured tensile load to a post-installed anchor to verify that it achieves the required holding strength in the substrate.

(CFB) Certified Field Builder Practice Test

(CFB) Certified Field Builder Practice Test

CFB Quality Control & Inspection 3