LECTURE 1 Flashcards
Major structural materials
Stell, wood concrete for masonry
concrete definition
a heavy rough building material made rom a mixture of broken stone or gravel sand cement and water that can be spread or poured into molds and that forms a mass resembling stone on hardnening
COnc Ingredients
CA
FA
W
C
additives
aggreate is about what percent of volume
60 to 75
aggregate is what percent of mass
70 to 85
Ideal aggregates are
hard, little void durable clean
border between coarse and fine
4.75 mm sieve, sand is <5mm gravel is >5mm
aggreagte weight classes
light. 1350-1850
normal 2200-2400
heavy 2900-6100
Types of normal aggregate
natural, manufactured,recycled,marine dregded
types of heavy weight aggregate
barite magnetite
iron and steel
limonite
how should aggregates be
hard, not easily split
less void less porosity
durable particles
clean
free of absorbed chemicals
free of coating of clay
why are quality aggregates important
to make concrete strong
to make concrete durable
to avoid dangering the hydration
to maintain a good bond between the aggregate and the cement paste
types of lightweight aggregate
expanded shale
pumice
slag
slate
clay
