Mix design of Concrete: British (DOE) method B. Bhattacharjee ...
Transcript of Mix design of Concrete: British (DOE) method B. Bhattacharjee ...
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
CEL 774 CONSTRUCTION PRACTISESCONSTRUCTION PRACTISES
Mix design of Concrete: British (DOE) method
B. Bhattacharjee
CIVIL ENGINEERING DEPARTMENTIIT DELHI
General Outline
• The DOE method • Mix design with Fly ash
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
DOE METHOD
f m =f ck + 1.65σStep 1 : selection of w/c from curvesStep 2: Estimate water content based on
slump/Ve-be time, m.s.a and shape of aggregate
Step 3: Calculate cement content Step 4: Wet density of concrete & total aggregate content
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
DOE METHOD
Step 5 : Determination of FA based on m.s.a and w/c and grading zone of sand from curves
–Apparently most logical way of choosing w/c–Takes shape of aggregate in to account–A mix design procedure with FA is also available
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
DOE METHOD
w/c determination
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Crushed 40
Uncrushed 47
OPC or
SRC
28 days compressive strength
Equation for w/c curves
1-21
w/c21
and
; law) s(Abraham' Strength
where
BKAKB
Af
KKf
cw
==
==
×=
[ ]47.60ln11.58 5.01 −×= fK
⎥⎦
⎤⎢⎣
⎡ −84.6371
176.540
=20.5f
K
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
DOE METHODwater content determination
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
m.s.a Type Slump 0-10
S 10-30 mm
S 60-180 mm
U-Crshd 135 160 195
Crshd 170 190 225
U-Crshd 115 140 175
Crshd 155 175 205
40 mm
20 mm
Step 4: Calculate cement content
w/cw/c*= Min (w/c*= Min (w/ccurvecurve, w/c, w/cdurabilitydurability) ) ..
C=Max(W/ w/c*, Cdurability).
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
In case of CA & FA are different W=2/3Wf+1/3Wc
DOE METHODStep 4: Wet density (Dwet) of concrete
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Step 4: Calculate total Aggregate content
Total aggregate content (Total aggregate content (WWaggagg)= Wet )= Wet densitydensity--CC--W W ..
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Step 5 : Determination of FA based on m.s.a and w/c and grading zone of sand from curves
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Step 5 : Determination of FA
% passing through 600 Micron sieve1 – 152 – 403 – 604 – 805 – 100
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Step 5 : Determination of FA
% passing through 600 Micron sieve1 – 152 – 403 – 604 – 805 – 100
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
% passing through 600 Micron sieve1 – 152 – 403 – 604 – 805 – 100
Step 5 : Determination of FA
Step 5: Calculate Fine Aggregate content
Fine aggregate content Fine aggregate content FFaggagg = = ppww×× ((WWaggagg) ) kg/mkg/m33..
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
pw is determined from graphs
Cagg= Wagg-Fagg
When fly ash (PFA) is used in the mix control mix proportions are calculated as usual
Total percentage of PFA (pTotal percentage of PFA (pff) is fixed as ) is fixed as specified/desiredspecified/desired..
DOE METHOD
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Water content is reduced depending on pf
W'= W-ΔW
DOE METHODwater content reduction
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
FA in Cement (%)
Slump 0-10
S 10-30 mm
S 60-180 mm
10 5 5 10
20 10 10 15
40 20 20 25
DOE METHODCement and FA contents
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
– p=F/(C'+F)×100; F=pC'/(100-p)
C'=[100-p]W' /[(100-0.7p)(W/C)*]k=0.3
For durability max W/(C+F) with max p =25% or as per IS 1489 Part I
W/C*=W'/ (C' +kF)
DOE METHODWet density is assumed same as control mix
B. Bhattacharjee
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
Fine aggregate content is calculated as before
Total aggregate content= Dwet - C‘-W'-F
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
SummaryDOE method
Mix design with PFA
DEPARTMENT OF CIVIL ENGINEERING, IIT DELHI
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