CSI Construction Materials & Systems 2 — Questions and Answers
Question 1: Which ASTM standard governs the testing of compressive strength for hydraulic cement mortars?
- ASTM C109 (Correct answer)
- ASTM C150
- ASTM C270
- ASTM C387
Correct answer: ASTM C109
ASTM C109 covers the standard test method for compressive strength of hydraulic cement mortars using 2-inch cube specimens.
Question 2: In curtain wall systems, what is the primary function of a pressure plate?
- To provide thermal insulation between panels
- To clamp the glazing or infill panel to the framing member (Correct answer)
- To allow differential movement between stories
- To drain condensation from the glazing cavity
Correct answer: To clamp the glazing or infill panel to the framing member
Pressure plates mechanically clamp glazing or infill panels against a structural gasket on the curtain wall framing, securing them in place.
Question 3: What distinguishes Type S mortar from Type N mortar per ASTM C270?
- Type S has lower compressive strength and higher flexibility
- Type S has higher compressive strength and is used where high lateral loads occur (Correct answer)
- Type S is used exclusively for interior non-load-bearing partitions
- Type S contains no lime and relies solely on Portland cement
Correct answer: Type S has higher compressive strength and is used where high lateral loads occur
Type S mortar has a minimum compressive strength of 1,800 psi and is used where high lateral loads from wind or seismic forces must be resisted.
Question 4: Which roofing membrane system relies on the weight of ballast rather than mechanical fasteners or adhesive to remain in place?
- Fully adhered single-ply
- Mechanically fastened TPO
- Loose-laid ballasted EPDM (Correct answer)
- Self-adhered modified bitumen
Correct answer: Loose-laid ballasted EPDM
Loose-laid ballasted EPDM systems are held down by gravel or pavers placed on top of the membrane rather than by fasteners or adhesive.
Question 5: In a suspended acoustical ceiling system, what component directly supports the main runner?
- Cross tee
- Wall angle
- Hanger wire (Correct answer)
- Carrying channel
Correct answer: Hanger wire
Hanger wires attach to the structure above and support the main runners (carrying tees) of a suspended acoustical ceiling grid.
Question 6: What is the key advantage of using glass fiber reinforced concrete (GFRC) for architectural cladding panels?
- It eliminates all thermal bridging at panel connections
- It achieves high strength at significantly reduced panel weight (Correct answer)
- It is impervious to UV degradation without any coating
- It requires no control joints regardless of panel size
Correct answer: It achieves high strength at significantly reduced panel weight
GFRC panels achieve compressive strengths comparable to conventional concrete but at roughly one-quarter the weight, enabling thinner, lighter cladding panels.
Question 7: Which term describes the measure of a material's resistance to water vapor transmission?
- Permeance (Correct answer)
- Absorptance
- Emittance
- Transmittance
Correct answer: Permeance
Permeance, expressed in perms, measures how readily water vapor passes through a material; lower permeance indicates a better vapor retarder.
CSI Construction Materials & Systems 2
Which ASTM standard governs the testing of compressive strength for hydraulic cement mortars?