QUESTIONS & ANSWERS
What is aggregate used for in concrete? - ANS ✔✔as reinforcement to add strength to the
overall composite material
What are some drainage applications of concrete? - ANS ✔✔foundations, well drains, edge
drains
What are the 2 types of aggregate? - ANS ✔✔natural and synthetic
What are the 3 types of natural aggregate (the 3 rock types)? - ANS ✔✔igneous, sedimentary,
metamorphic
Volcanic rock is what kind of rock? - ANS ✔✔igneous
Are the natural properties of (natural) aggregate changed during preparation? How is rock
changed during preparation? - ANS ✔✔no, crushing, sorting, washing
What is the typical bulk density of natural aggregate? - ANS ✔✔95 pcf
What is the typical bulk density of volcanic rock? - ANS ✔✔70 pcf
What are the 3 ways synthetic aggregate is produced? - ANS ✔✔byproducts of industrial
processes, products of special aggregate processes, recycled or waste materials
Where is natural aggregate sourced from? - ANS ✔✔quarries and natural deposits
, What are some uses of aggregate/concrete (besides drainage applications)? - ANS
✔✔foundations, roads, grout, railroads, plaster, filler
What institutions provide standards for aggregate? - ANS ✔✔ASTM and state DOTs
What are some examples of synthetic aggregate? - ANS ✔✔tire chips, steel punchings,
glassphalt
What are the 5 common shapes of aggregate? - ANS ✔✔angular, rounded, flaky, elongated,
flaky and elongated
Synthetic aggregate is more/less common and more/less expensive than natural aggregate. -
ANS ✔✔less, more
What does aggregate shape dictate? - ANS ✔✔application, use, how it interlocks, slides, and
rolls
What are the main shape properties of aggregate? - ANS ✔✔angularity and flakiness
What does an aggregate shape depend on? - ANS ✔✔composition and processing
What aggregate is usually used in Portland Cement concrete? - ANS ✔✔natural gravel
What aggregate is usually used in asphalt concrete? - ANS ✔✔crushed stone
What are the main contributors to aggregate instability/lack of durability? - ANS ✔✔oxidation,
hydration, carbonation, alkali reactivity, freeze-thaw cycles, chemical degradation, mechanical
breakdown during handling, volume changes due to water absorption