A concrete foundation wall shows honeycomb defects after form removal. What was the most likely cause?
Correct Answer
B) Insufficient vibration during placement
Honeycomb defects (voids and rough surfaces) typically result from insufficient vibration during concrete placement. Proper vibration consolidates the concrete and eliminates air voids, ensuring a dense, smooth surface.
Why This Is the Correct Answer
Honeycomb defects are characterized by voids, air pockets, and rough surfaces in hardened concrete that occur when concrete is not properly consolidated during placement. Insufficient vibration fails to remove trapped air and doesn't allow the concrete to flow around reinforcement and into all areas of the forms. This results in the characteristic honeycomb appearance with visible aggregate and voids. Proper vibration is essential to achieve dense, uniform concrete with smooth surfaces.
Why the Other Options Are Wrong
Option A: Water-cement ratio was too low
A low water-cement ratio typically produces stronger concrete but may make it harder to work with. However, this would not directly cause honeycomb defects if proper vibration techniques are used during placement.
Option D: Concrete was placed too quickly
Early form stripping affects surface finish and can cause surface damage, but honeycomb defects are internal voids that form during placement, not during form removal. The defects would be present regardless of stripping time.
Memory Technique
Think 'Honeycomb = Holes from No Buzz' - the holes (voids) come from lack of vibration (buzz) during placement
Reference Hint
ACI 318 Building Code Requirements for Structural Concrete, Chapter on Concrete Placement and Consolidation
More Project Mgmt Questions
What is the minimum R-value required for wall insulation in Florida Climate Zone 2?
A subcontractor brings a new chemical product to your jobsite. Under the Globally Harmonized System (GHS), what information must be immediately available to workers?
A construction site has a trench that is 8 feet deep in Type B soil. What is the maximum allowable slope ratio for the trench walls without protective systems?
What is the maximum recommended spacing between drywall screws when attaching to wood studs?
Your crew discovers suspected asbestos-containing materials during a renovation project. What is the first action you should take?
A scaffold platform is 12 feet long and 5 feet wide. If the maximum load capacity is 25 pounds per square foot, what is the total weight capacity of this platform?
Which CSI MasterFormat Division would contain specifications for fire-stopping and firesafing materials?
In tilt-up concrete construction, what is the primary advantage of this method over conventional cast-in-place construction?
Which OSHA standard specifically addresses construction industry safety and health regulations?
A structural drawing shows a beam labeled 'W12x26'. What does the '26' represent?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass