Rei
forcedCo
crete
Plai
co
creteisformedfromaharde
edmixtureofceme
t，waterfi
eaggregate，coarseaggregate（crushedsto
eorgravelaira
dofte
otheradmixturesTheplasticmixisplaceda
dco
solidatedi
theformwork，the
curedtofacilitatetheacceleratio
ofthechemicalhydratio
reactio
lftheceme
twatermix，resulti
gi
harde
edco
creteThefi
ishedproducthashighcompressivestre
gth，a
dlowresista
cetote
sio
，suchthatitste
silestre
gthisapproximatelyo
ete
thlfitscompressivestre
gth。Co
seque
tly，te
silea
dshearrei
forceme
ti
thete
sileregio
sofsectio
shastobeprovidedtocompe
satefortheweakte
sio
regio
si
therei
forcedco
creteeleme
t
Itisthisdeviatio
i
thecompositio
ofarei
forcesco
cretesectio
fromthehomoge
eityofsta
dardwoodorsteelsectio
sthatrequiresamodifiedapproachtothebasicpri
ciplesofstructuraldesig
。Thetwocompo
e
tsoftheheteroge
eousrei
forcedco
cretesectio
aretobesoarra
geda
dproportio
edthatoptimaluseismadeofthematerialsi
volvedThisispossiblebecauseco
creteca
easilybegive
a
ydesiredshapebyplaci
ga
dcompacti
gthewetmixtureoftheco
stitue
ti
gredie
tsareproperlyproportio
edthefi
ishedproductbecomesstro
gdurable，a
d，i
combi
atio
withtherei
forci
gbarsadaptableforuseasmai
membersofa
ystructuralsystem
Thetech
iques
ecessaryforplaci
gco
cretedepe
do
thetypeofmembertobecast：thatis，whetheritisacolum
abea
，awall，aslab，afou
datio
amasscolum
sora
exte
sio
ofpreviouslyplaceda
dharde
edco
crete。Forbeams，colum
sa
dwalls，theformsshouldbewelloiledafterclea
i
gthem，a
dtherei
forceme
tshouldbeclearedofrusta
dotherharmfulmaterialsI
fou
datio
stheearthshouldbecompacteda
dthoroughlymoiste
edtoabout6i
i
depthtoavoidabsorptio
ofthemoistureprese
ti
thewetco
creteCo
creteshouldalwaysbeplacedi
horizo
tallayerswhicharecompactedbymea
sofhighfreque
cypowerdrive
vibratorsofeithertheimmersio
orexter
altype，asthecaserequires，u
lessitisplacedbypumpi
gItmustbekepti
mi
dhoweverthatovervibratio
ca
beharmfulsi
ceitcouldcausesegregatio
oftheaggregatea
dbleedi
goftheco
crete
6
fHydratio
oftheceme
ttakesplacei
theprese
ceofmoistureattemperaturesabove50°F。Itis
ecessarytomai
tai
suchaco
ditio
i
orderthatthechemicalhydratio
reactio
ca
takeplace。Ifdryi
gistoorapid，surfacecracki
gtakesplaceThiswouldresulti
reductio
ofco
cretestre
gthduetocracki
gaswellasthefailuretoattai
fullchemicalhydratio
。
Itisclearthatalarge
umberofparametershavetobedealtwithi
proportio
i
garei
forcedco
creteeleme
tsuchasgeometricalwidth，depthareaofrei
forceme
tsteelstrai
，co
cretestrai
steelstress，ar