Construction Materials & Systems Flashcards

What is the primary difference between 'open-web steel joists' (OWSJs) and conventional steel beams?

Answer: OWSJs use a truss-like configuration that allows mechanical systems to pass through the web

Open-web steel joists use a truss configuration with open triangular panels in the web, allowing HVAC ducts, pipes, and conduit to pass through the joist depth.

Which type of expansion joint filler material is used in concrete slabs to accommodate thermal movement and prevent debris intrusion?

Answer: Fiber expansion joint filler board

Fiber expansion joint filler board (typically cork or cellulose fiber) is placed full-depth in slab expansion joints to allow compression from thermal expansion while keeping debris out.

In curtain wall design, what does the term 'stack joint' refer to?

Answer: The horizontal joint between vertically stacked glass units in a unitized panel system

A stack joint in unitized curtain wall systems is the horizontal joint where the bottom of one unit overlaps or interlocks with the top of the unit below.

What is the principal function of fly ash when used as a supplementary cementitious material (SCM) in concrete?

Answer: It reacts with calcium hydroxide from cement hydration to form additional binding compounds

Fly ash (a pozzolan) reacts with the calcium hydroxide byproduct of Portland cement hydration to form additional calcium silicate hydrate (CSH), improving long-term strength and durability.

In a rainscreen cladding system, what role does the pressure-equalized cavity play?

Answer: It equalizes air pressure across the cladding to eliminate the pressure differential driving water inward

By equalizing air pressure between the exterior and the cavity, the pressure-equalized rainscreen eliminates the driving force that would otherwise push water through cladding joints.

What distinguishes 'hardwood' from 'softwood' in the context of building materials?

Answer: Hardwoods come from deciduous (broad-leaved) trees; softwoods from coniferous (needle-bearing) trees

The hardwood/softwood distinction is botanical: hardwoods come from angiosperm (deciduous) trees and softwoods from gymnosperm (coniferous) trees, regardless of actual wood density.

Which fire-resistance rating system component is defined as the assembly's ability to prevent flame or hot gases from passing through to the unexposed side?

Answer: Integrity (flame spread)

The 'integrity' criterion in fire-resistance testing measures whether the assembly prevents the passage of flames or hot gases through cracks or openings to the unexposed face.