Advanced Aggregate Characterization Flashcards

Which test method is used to evaluate the soundness of aggregates by measuring resistance to disintegration using sodium or magnesium sulfate?

Answer: ASTM C88 Sulfate Soundness

ASTM C88 evaluates aggregate soundness by cycling samples through sodium or magnesium sulfate solutions and measuring mass loss after multiple cycles.

In the Micro-Deval abrasion test for fine aggregate, what liquid medium is used during the test?

Answer: Water

The Micro-Deval test uses water along with steel ball charges to abrade aggregate, simulating wet abrasion conditions encountered in service.

What is the maximum allowable magnesium sulfate soundness loss for coarse aggregate used in severe exposure concrete per CSA A23.1?

Answer: 12%

CSA A23.1 limits magnesium sulfate soundness loss to 12% for coarse aggregate in severe exposure concrete to ensure adequate freeze-thaw durability.

During a freeze-thaw durability test on coarse aggregate, which parameter is typically measured to assess performance?

Answer: Durability factor based on mass loss

Freeze-thaw durability is assessed by calculating a durability factor based on mass loss after a specified number of freeze-thaw cycles.

Which petrographic feature in coarse aggregate is most directly associated with accelerated alkali-silica reaction (ASR) susceptibility?

Answer: Strained quartz and microcrystalline silica

Strained quartz and microcrystalline or cryptocrystalline silica are the petrographic features most directly associated with ASR susceptibility.

What is the primary purpose of determining the aggregate crushing value (ACV) in advanced characterization?

Answer: Assess resistance to mechanical degradation under load

The aggregate crushing value measures resistance to crushing under a progressively applied compressive load, indicating mechanical strength of the aggregate.

In ASTM C295 petrographic examination, what percentage of reactive mineral constituents in coarse aggregate is typically considered the threshold requiring further chemical testing?

Answer: 5%

ASTM C295 guidelines suggest that reactive mineral constituents exceeding approximately 5% warrant further chemical testing to assess actual ASR potential.