BArch Bachelor of Architecture Building Materials & Construction Technology 1 — Questions and Answers
Question 1: What is the water-to-cement (w/c) ratio's primary effect on hardened concrete?
- Lower w/c ratio produces higher strength and durability (Correct answer)
- Higher w/c ratio increases compressive strength
- w/c ratio affects only workability, not strength
- Lower w/c ratio increases permeability
Correct answer: Lower w/c ratio produces higher strength and durability
A lower water-to-cement ratio produces denser, stronger concrete because excess water creates voids (capillary pores) that reduce strength and increase permeability.
Question 2: Which roofing membrane system consists of multiple layers of bitumen-saturated felts bonded with hot asphalt or coal tar?
- Built-up roofing (BUR) (Correct answer)
- Single-ply TPO membrane
- Standing seam metal roof
- Spray polyurethane foam (SPF)
Correct answer: Built-up roofing (BUR)
Built-up roofing (BUR) is a traditional flat roof system composed of alternating layers of bituminous felts and hot mopped asphalt or coal tar, topped with aggregate.
Question 3: In masonry construction, what is the purpose of a weep hole at the base of a cavity wall?
- Allow water that enters the cavity to drain out (Correct answer)
- Provide ventilation to the wall interior
- Relieve thermal expansion pressure
- Anchor the brick veneer to the backup
Correct answer: Allow water that enters the cavity to drain out
Weep holes are small openings left in mortar joints at the base of cavity walls to allow moisture that infiltrates the cavity to drain to the exterior.
Question 4: Gypsum board (drywall) achieves its fire-resistant properties primarily because:
- It contains chemically combined water that absorbs heat when released (Correct answer)
- It is made of non-combustible steel fibers
- Its paper facing char prevents burning
- It has low thermal conductivity
Correct answer: It contains chemically combined water that absorbs heat when released
Gypsum (CaSO₄·2H₂O) contains about 21% chemically combined water by weight; when exposed to fire, this water is driven off as steam, absorbing heat and delaying temperature rise.
Question 5: What is the primary difference between tempered glass and laminated glass in terms of failure behavior?
- Tempered glass shatters into small cubes; laminated glass holds together in a sheet (Correct answer)
- Laminated glass shatters into sharp shards; tempered stays intact
- Both fail identically under impact
- Tempered glass is stronger but laminated glass is thicker
Correct answer: Tempered glass shatters into small cubes; laminated glass holds together in a sheet
Tempered glass is heat-strengthened and, when broken, shatters into small, relatively blunt cubes; laminated glass has a PVB interlayer that holds broken pieces together.
Question 6: Which insulation material has the highest R-value per inch and is commonly used where space is limited?
- Closed-cell spray polyurethane foam (ccSPF) (Correct answer)
- Fiberglass batt
- Mineral wool
- Cellulose blown-in
Correct answer: Closed-cell spray polyurethane foam (ccSPF)
Closed-cell spray polyurethane foam achieves approximately R-6 to R-7 per inch, the highest among common insulation materials, due to its low-conductivity blowing agent trapped in closed cells.
BArch Bachelor of Architecture Building Materials & Construction Technology 1
What is the water-to-cement (w/c) ratio's primary effect on hardened concrete?