FCC Concrete & Masonry Construction 2 — Questions and Answers
Question 1: What is the water-cement ratio (w/c) relationship to concrete strength?
- Higher w/c ratio produces stronger concrete
- Lower w/c ratio produces stronger concrete (Correct answer)
- Water-cement ratio has no effect on strength
- A w/c ratio of 0.70 is ideal for maximum strength
Correct answer: Lower w/c ratio produces stronger concrete
A lower water-cement ratio results in denser concrete with fewer voids, producing higher compressive strength as established by Abrams' Law.
Question 2: How long must freshly placed concrete be cured under normal Florida temperature conditions to achieve adequate early strength?
- 1 day
- 3 days
- 7 days (Correct answer)
- 28 days
Correct answer: 7 days
A minimum of 7 days of moist curing is typically required for normal Portland cement concrete to develop sufficient early strength and durability.
Question 3: When laying CMU block walls, mortar joints are typically how thick according to standard masonry practice?
- 1/4 inch
- 3/8 inch (Correct answer)
- 1/2 inch
- 3/4 inch
Correct answer: 3/8 inch
Standard masonry practice specifies 3/8-inch mortar joints for CMU block walls, providing adequate bond and consistent coursing dimensions.
Question 4: In Florida, rebar placed in masonry cells must be grouted when the bar size exceeds what diameter?
- #3 bar
- #4 bar
- #5 bar
- All cells with rebar must be grouted (Correct answer)
Correct answer: All cells with rebar must be grouted
All masonry cells containing reinforcing bars must be fully grouted to ensure proper load transfer and to protect the steel from corrosion.
Question 5: Which ASTM standard governs the specification of portland cement used in Florida concrete construction?
- ASTM C33
- ASTM C150 (Correct answer)
- ASTM C94
- ASTM C90
Correct answer: ASTM C150
ASTM C150 is the standard specification for Portland cement, defining the requirements for the eight types of Portland cement used in construction.
Question 6: What is the primary purpose of air entrainment in concrete mixes used in Florida?
- To increase compressive strength
- To improve workability and reduce bleed water (Correct answer)
- To speed up the set time in hot weather
- To increase the water-cement ratio
Correct answer: To improve workability and reduce bleed water
Air entrainment improves workability and reduces bleeding and segregation; while freeze-thaw resistance is critical in northern climates, in Florida the workability benefit is primary.
Question 7: When building a masonry retaining wall in Florida, the Florida Building Code requires that weep holes be provided at what minimum spacing?
- 24 inches on center
- 32 inches on center
- 48 inches on center (Correct answer)
- No weep holes are required if drainage fill is used
Correct answer: 48 inches on center
The Florida Building Code requires weep holes at maximum 4-foot (48-inch) intervals along the base of masonry retaining walls to relieve hydrostatic pressure.
FCC Concrete & Masonry Construction 2
What is the water-cement ratio (w/c) relationship to concrete strength?