Difficulty: Easy
Correct Answer: A waterproofing layer over roofs made from asphalt with fillers to achieve a plastic, trowelable consistency.
Explanation:
Introduction / Context:
Bituminous materials appear in many forms: cutbacks, emulsions, mastic, plastic asphalt, and more. Distinguishing these helps select the right material for waterproofing, patching, or paving applications.
Given Data / Assumptions:
Concept / Approach:
Plastic asphalt is essentially asphalt combined with suitable mineral fillers (and sometimes fibers/plasticizers) to produce a plastic, workable mass used as a roofing or waterproofing layer and for patch repairs. It differs from mastic asphalt mainly by formulation and application specifics but sits in the same family of dense, low-void, trowel-applied mixes.
Step-by-Step Solution:
Verification / Alternative check:
Construction manuals list plastic/mastic asphalt for roofing and waterproofing where a jointless, impermeable layer is desired.
Why Other Options Are Wrong:
Portland cement with asphalt does not make standard plastic asphalt. Natural asphalt is unmodified source material. Generic refinery description and epoxy–bitumen hybrids are not standard definitions here.
Common Pitfalls:
Confusing plastic asphalt with asphalt emulsion or hot mix asphalt; each has different composition and use cases.
Final Answer:
A waterproofing layer over roofs made from asphalt with fillers to achieve a plastic, trowelable consistency.
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