LEcture 2 Flashcards
Three dictating strengths
aggregate paste and bond
quality natural aggregates are
igneous and metamorphic, not sedimentary
Materials at higher elevations that glacier have
better quality
manufactured aggregates atributes
texture, shape and size . ROUGH more angular or cubical or elongated and more uniform in grading
whgy use recycled concrete
help the earth
recyled concrete attributes
high absorption low specific gravity
marine dredged source
estuaries and seabeds, don’t use it it may contain seashells and salt
max aggregate size depends on
shape and size of concrete member\
amount and distribution of steel
as max aggregate size goes up
total surface covered by paste goes down
required water content and cement goes up
bulking is the..
increase in the total volume of moist fine aggregate over the same mass in a dry condition
to test abrasion use
los angeles test
why grading limits
workability
pumpability
economy
porosity
durability
shrinkage
the volume of cement paste is greater than the
voids between aggregates to provide workability and is influenced by the cohesiveness of the paste
water absorption capacity equation
(SSD-OVEN)/OVEN
moisture content equation
(SAMPLE-OVEN)/OVEN
If moisture content = A and absorption capacity = B then what to do when, A<B,A=B,A>B
add water,nothing,remove water
abrasion is the
physical wearing and grinding of a surface hrough friction and impact on the surface
