Water - Cement Ratio
-
Upload
barclay-palmer -
Category
Documents
-
view
32 -
download
2
description
Transcript of Water - Cement Ratio
![Page 1: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/1.jpg)
Water - Cement RatioWater - Cement Ratio
![Page 2: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/2.jpg)
Water/Cement RatioThe number of pounds of water per pound
of cement.A low ratio means higher strengths, a high
ratio means lower strengths.For NCDOT, the ratio depends on the class
of concrete, whether an air agent is used or not, and the shape of the stone - rounded or angular.
![Page 3: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/3.jpg)
W/C Ratio Cont.
Example:W/C = 0.500, and Water = 250 pounds
How much cement is needed?
250 / 0.500 = 500 pounds of `````````````````````` cement
![Page 4: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/4.jpg)
W/C Ratio Cont.Example:
W/C = 0.500, and Cement = 600
pounds
How much water is needed?
0.500 X 600 = 300 pounds of water
300 pounds / 8.33 = 36.0 gallons
![Page 5: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/5.jpg)
Water/Cementitious Problem
Cement Used in Mix – 436 poundsFly Ash in Mix – 131 poundsMaximum Water – 36.0 gallonsTotal Water – 33.5 gallonsMetered Water – 27.5 gallonsFree Water in aggregates – 50 pounds
Determine the design w/c ratio and the batched w/c ratio
![Page 6: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/6.jpg)
SOLUTION: Design W/CAdd Cement And Fly Ash:
436 + 131 = 567 pounds
Convert Design Water Into Pounds:
33.5 X 8.33 = 279 pounds
Plug Into Formula W/C = Ratio:
279 / 567 = 0.492 (carry answer to three places after decimal)
![Page 7: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/7.jpg)
Batched W/C Ratio
Add Cement And Fly Ash:
436 + 131 = 567 pounds
Convert Metered Water Into Pounds:
27.5 X 8.33 = 229 pounds
Add free water 229 + 50 = 279 Lbs
279 / 567 = 0.492
![Page 8: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/8.jpg)
W/C Ratio with Ice
Determine the W/C ratio if 68 pounds of ice is used to lower the temperature of the concrete.
The W/C ratio remains the same because the quantity of total water does not change.
![Page 9: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/9.jpg)
QUESTIONS
![Page 10: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/10.jpg)
% Solids And VoidsIn determining mix designs, you must
use an aggregate dry rodded unit weight.This weight is determined at the lab.In the procedure for determining this
weight, only the coarse aggregate is used.Therefore, there is a % of solids and a %
of voids in the container.
![Page 11: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/11.jpg)
Formula : % Solids & Voids% Solids:
Dry Rodded Unit Weight
(Spec. Gravity) X (62.4)
The Answer Is Then Multiplied Times 100
To get % Voids:
Subtract % Solids from 100
![Page 12: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/12.jpg)
Example:Dry Rodded Unit Weight: 96.6 pcf
Specific Gravity Of Agg.: 2.80
% Solids = 96.6 = 0.553 (2.80 X 62.4)
0.533 X 100 = 55%
% Voids = 100 - 55 = 45%
![Page 13: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/13.jpg)
Terms I Should Know….Abrasion Resistance of an AggregateDurabilityHydrationPhSaturated Surface DrySet RetarderUnit WeightWater / Cement RatioTHAT IS ENOUGH FOR A MONDAY!!
![Page 14: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/14.jpg)
Pass Out Day 1 Mix Design Problems
![Page 15: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/15.jpg)
PROBLEM SOLUTION1.Water: 209 + 15 = 224 gals
224 X 8.33 = 1866 poundsAdd all material:
4060+7733 +13,586 +1866 = 27,245 Divide by unit weight:
27,245 = 7.1 cu. yd.
(142.10 X 27)
![Page 16: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/16.jpg)
PROBLEM SOLUTION2. Water / Cement = Ratio
1866 / 4060 = 0.460
3. (A) % Solid
88.6 = 0.508 X 100 = 51%
(2.79 X 62.4)
(B) % Void = 100 – 51 = 49%
![Page 17: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/17.jpg)
PROBLEM SOLUTION4. Wet Sand:
5.9 - 0.5 = 5.4% 5.4 / 100 = 0.054
0.054 X 1102 = 59.5 pounds
1102 + 60 = 1162 pounds (batch weight)
Dry Sand:
0.5 / 100 = 0.005
0.005 X 1102 = 5.5 pounds
1102 - 6.0 = 1096 pounds
![Page 18: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/18.jpg)
PROBLEM SOLUTION5. SSD sand weight ?
1720 / 1.062 = 1620 pounds SSD sand
![Page 19: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/19.jpg)
PROBLEM SOLUTION
6. Gallons of Water from Wet Sand
1720 – 1620 = 100 pounds / 8.33 = 12.0 gallons
![Page 20: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/20.jpg)
HOMEWORK PROBLEM
![Page 21: Water - Cement Ratio](https://reader035.fdocuments.in/reader035/viewer/2022062308/56813082550346895d965e92/html5/thumbnails/21.jpg)
QUESTIONS