CDS Materials & Equipment Knowledge 2 — Questions and Answers
Question 1: Which type of explosive is classified as a 'low explosive' commonly used in demolition blasting agents?
- ANFO (Ammonium Nitrate/Fuel Oil) (Correct answer)
- RDX (Research Department Explosive)
- PETN (Pentaerythritol tetranitrate)
- TNT (Trinitrotoluene)
Correct answer: ANFO (Ammonium Nitrate/Fuel Oil)
ANFO is a low-velocity blasting agent commonly used in demolition due to its relative safety and low cost.
Question 2: A wrecking ball used in demolition is typically made of what material?
- Reinforced concrete
- Cast iron or steel (Correct answer)
- Aluminum alloy
- Carbon fiber composite
Correct answer: Cast iron or steel
Wrecking balls are typically made of cast iron or steel to provide the necessary mass and durability for impact demolition.
Question 3: What is the primary purpose of a dust suppression system on a demolition excavator?
- To cool the hydraulic system
- To lubricate the breaker attachment
- To minimize airborne particulate during demolition activities (Correct answer)
- To prevent static electricity buildup
Correct answer: To minimize airborne particulate during demolition activities
Dust suppression systems spray water mist to capture airborne particulates, reducing worker exposure and regulatory violations.
Question 4: What does the term 'pre-weakening' refer to in demolition practice?
- Using chemicals to soften concrete before cutting
- Structurally compromising a building prior to primary demolition (Correct answer)
- Applying water to weaken masonry mortar joints
- Removing all non-load-bearing walls first
Correct answer: Structurally compromising a building prior to primary demolition
Pre-weakening involves selectively removing or cutting structural elements before the primary demolition method is applied to control the collapse direction.
Question 5: Which type of saw blade is most appropriate for cutting through reinforced concrete containing rebar?
- Carbide-tipped circular saw blade
- Diamond segmented blade (Correct answer)
- High-speed steel (HSS) blade
- Bimetallic reciprocating blade
Correct answer: Diamond segmented blade
Diamond segmented blades are designed to cut through both concrete matrix and embedded rebar without rapid wear.
Question 6: What is the function of a hydraulic muncher (pulverizer) attachment in concrete demolition?
- It drills pilot holes for explosive placement
- It crushes and separates concrete from reinforcing steel simultaneously (Correct answer)
- It applies controlled pressure to crack concrete along pre-cut lines
- It vacuums concrete dust during cutting operations
Correct answer: It crushes and separates concrete from reinforcing steel simultaneously
A hydraulic pulverizer uses jaw-like crushing action to break concrete and simultaneously expose and separate embedded rebar for recycling.
Question 7: Asbestos-containing pipe insulation removed during demolition is classified as which waste type under EPA regulations?
- RCRA Hazardous Waste
- Regulated Asbestos-Containing Material (RACM) (Correct answer)
- Universal Waste
- Solid Municipal Waste
Correct answer: Regulated Asbestos-Containing Material (RACM)
Friable asbestos pipe insulation qualifies as RACM under NESHAP regulations and requires specific handling, packaging, and disposal procedures.
CDS Materials & Equipment Knowledge 2
Which type of explosive is classified as a 'low explosive' commonly used in demolition blasting agents?