BC10

Question 1

concrete

Answer 1

hardened form of cement
course aggregates: gravel and stone
fine aggregates: sand

Question 2

admixtures

Answer 2

shale or clinker- reduces density of concrete
super plasticizers- flow more freely
coloring

Question 3

reinforced concrete

Answer 3

concrete is compressively strong and tensile weak
rebar, wire mesh and fiberglass

Question 4

rebar

Answer 4

3= 0.375 inches

largest #18= 2.257 inches
common #5= 0.625 inches

Question 5

stirrups

Answer 5

vertical reinforcing rebar to resist diagonal tension

Question 6

prestressing

Answer 6

tightens or preloads the reinforcing steel in concrete
compressive stresses counteract tensile stresses from applied load
pretensioning and post tensioning
pre stresses steel can fail at 725F

Question 7

post tensioning

Answer 7

steel is not bonded to concrete
stretched within and can snap back if cut
steel added after concrete has hardened

Question 8

pretensioning

Answer 8

steel added before steel has hardened takes on upward bend until load is applied

Question 9

concrete hardening

Answer 9

takes about 28 days

Question 10

curing temp

Answer 10

50-70F
over 100F won’t harden right

Question 11

concrete fire resistance

Answer 11

1-4 hours

Question 12

flat slab concrete frame

Answer 12

concrete slab with concrete columns
slab is 6-12 inches
building supporting light loads additional reinforcing isn’t necessary flat slab
heavy loads reinforced columns with drop panels or mushroom capitols

Question 13

waffle construction

Answer 13

slab and beam with beams running in two directions

Question 14

precast concrete slabs

Answer 14

more like steel frame than cast in place
solid slabs, hollow core, single tee, double tee slabs
solid slabs short spans up to 30 ft
tee slabs spans up to 120 ft

Question 15

tilt up construction

Answer 15

roof assembly needs to maintain structural integrity because if the roof fails the walls will fall outward