Marshalltown 59017 Mixer - Manual (Page 4)

3
2-OPERATION
DRUM SPEED
The mixer drum should revolve between 20 and 25 R.P.M.’s for best results in mixing
concrete. To obtain this speed using a 1725/1800 R.P.M. electric motor, use a 2” diameter
“A” section V-pulley.
If using a 6 to 1 speed reduction 3 H.P. gasoline engine, use a 6 ¼” diameter “A” section V-
pulley.
GETTING READY FOR MIXING
Lay out forms for your concrete floor, patio, driveway, sidewalk, etc.
The quality of concrete is directly related to the quality of the cement paste. The quality of
the paste, in turn, is directly related to the amount of water mixed with the cement. For a
given amount of cement, as the amount of mixing water is reduced, the strength of the paste
increases, making the concrete stronger and more durable.
The proportions by weight given in Table 1 can be used as a starting point to make 1 cu. Ft.
(0.028
m3 ) of strong, durable concrete. The proportions given in Table 2 are volumetric; 1
bag of cement is equal to 1 cu. ft. (0.28 m3 ) and weighs 94 lbs.
(42.6 kg). The Canadian bag of cement has a net mass of 40 kg.
The proportions are only a guide and may need adjustments to give a workable mix with
locally available aggregates.
T a b l e 1 . P r o p o r t i o n s b y W e i g h t t o M a k e 1 C u . F t . o f C o n c r e t e
A i r - e n t r a i n e d c o n c r e t e C o n c r e t e w i t h o u t a i r
C o u r s e C o u r s e
C e m e n t S a n d a g g r e g a t e W a t e r C e m e n t S a n d a g g r e g a t e W a t e r
l b l b l b l b l b l b l b l b
2 9 5 3 4 6 1 0 2 9 5 9 4 6 1 1
2 7 4 6 5 5 1 0 2 7 5 3 5 5 1 1
2 5 4 2 6 5 1 0 2 5 4 7 6 5 1 0
2 4 3 9 7 0 9 2 4 4 5 7 0 1 0
2 3 3 8 7 5 9 2 3 4 3 7 5 9
* I f c r u s h e d s t o n e i s u s e d , d e c r e a s e c o a r s e a g g r e g a t e b y 3 l b s a n d i n c r e a s e s a n d b y 3 l b s .
M e t r i c c o n v e r s i o n : 1 l b = 0 . 1 2 1 k g
1 0 l b s = 4 . 5 4 k g
1 i n . = 2 5 m m 1 C u . F t . = 0 . 0 2 8 m
3
T a b l e 2 . P r o p o r t i o n s b y V o l u m e *
A i r - e n t r a i n e d c o n c r e t e C o n c r e t e w i t h o u t a i r
C o u r s e C o u r s e
C e m e n t S a n d a g g r e g a t e W a t e r C e m e n t S a n d a g g r e g a t e W a t e r
l b l b l b l b l b l b l b l b
1 2 1 / 4 1 1 / 2 1 / 2 1 2 1 / 2 1 1 / 2 1 / 2
1 2 1 / 4 2 1 / 2 1 2 1 / 2 2 1 / 2
1 2 1 / 4 2 1 / 2 1 / 2 1 2 1 / 2 2 1 / 2 1 / 2
1 2 1 / 4 2 3 / 4 1 / 2 1 2 1 / 2 2 3 / 4 1 / 2
1 2 1 / 4 3 1 / 2 1 2 1 / 2 3 1 / 2
* T h e c o m b i n e d v o l u m e i s a p p r o x i m a t e l y 2 / 3 o f t h e s u m o f t h e o r i g i n a l b u l k v o l u m e s .
M a x i m u m -
s i z e c o u r s e
a g g r e g a t e i n .
1 1 / 2
3 / 8
1 / 2
3 / 4
1
1 1 / 2
M a x i m u m -
s i z e c o u r s e
a g g r e g a t e i n .
3 / 8
1 / 2
3 / 4
1

Portland Cement Association 1980