Materials for Civil and Construction Engineers (4th Edition)
4th Edition
ISBN: 9780134320533
Author: Michael S. Mamlouk, John P. Zaniewski
Publisher: PEARSON
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Textbook Question
Chapter 6, Problem 6.17QP
Students in the materials class prepared three mortar mixes with water to cement ratios of 0.50, 0.55, and 0.60. Three 2-in. mortar cubes were prepared for each mix. The cubes were cured for 7 days and then tested for compressive strength. The test results were as shown in Table P6.17.
Determine the following:
a. The compressive strength of each cube.
b. The average compressive strength for each mix.
c. Plot the average compressive strength versus w/c ratios for all mixes.
d. Comment on the effect of increasing w/c ratio on the compressive strength of the cubes.
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Students have asked these similar questions
A concrete mix includes the following ingredients per cubic meter:
Cement%3D400 kg
Water=184 kg
No admixture
Table below shows possible alternatives mix ingredients. Indicate in the appropriate boxes in the
table what will happen in each case for the workability and the ultimate compressive strength as
increase, decrease or approximately the same.
What will happen?
Cement
Water
Admixture
(kg)
(kg)
Ultimate compressive
Workability
strength
400
225
None
449
184
None
Water
400
184
Reducer
Water
400
128
Reducer
400
184
Super
Plasticizer
400
184
Air Entrainer
400
184
Accelerator
DFocus
2. In a ready-mix concrete plant, cylindrical samples are prepared and tested periodically to detect
any mix problem and to ensure that the compressive strength is higher than the lower specification limit.
The minimum target value was set at 5,000 psi. The following compressive strength data were collected.
Sample
No.
1
2
3
4
5
6
7
8
9
10
Compressive
strength (psi)
5595
5139
6359
5192
5188
5241
5964
5875
6155
5115
Sample
No.
11
12
13
14
15
16
17
18
19
20
Compressive
strength (psi)
6695
5449
5278
6697
5195
6021
5320
5657
6595
5235
a. Calculate the mean, standard deviation, and the coefficient of variation of the data
b. Using a spreadsheet program, create a control chart for these data showing the target value and the
lower specification limit. Is the plant production meeting the specification requirement? If not, comment
on possible reasons. Comment on the data scatter.
6.31 The results of a laboratory experiment to evaluate the effects of a plasticizer
are shown below.
a. Calculate the water/cement in each of the three cases.
b. Using water reducer, how can we increase the compressive strength of con-
crete without changing workability? Refer to the appropriate case in the table.
244
Chapter 6 Portland Cement, Mixing Water, and Admixtures
With Water Reducer
Without Water
Reducer
Case 1
Case 2
Case 3
Cement Content, kg/m
850
850
850
765
Water Content, kg/m
Slump, mm
Compressive Strength, MPa
465
465
370
419
50
100
50
50
37.8
38.0
46
37.9
c. Using water reducer, how can we improve workability without channging
the compressive strength? Refer to the appropriate case in the table.
d. Using water reducer, how can we reduce cost without changing workability
or strength? (Assume that the cost of the small amount of water reducer
added is less than the cost of cement.) Refer to the appropriate case in the
table.
Summarize all possible effects of water…
Chapter 6 Solutions
Materials for Civil and Construction Engineers (4th Edition)
Ch. 6 - What ingredients are used for the production of...Ch. 6 - What is the role of gypsum in the production of...Ch. 6 - What is a typical value for the fineness of...Ch. 6 - What are the primary chemical reactions during the...Ch. 6 - Define the C-S-H phase of cement paste.Ch. 6 - What are the four main chemical compounds in...Ch. 6 - Prob. 6.7QPCh. 6 - Define a. interlayer hydration space b. capillary...Ch. 6 - Prob. 6.9QPCh. 6 - The following laboratory tests are performed: a....
Ch. 6 - What is a false set of portland cement? State one...Ch. 6 - The watercement ratio is important because it...Ch. 6 - Discuss the effect of watercement ratio on the...Ch. 6 - Draw a graph to show the general relationship...Ch. 6 - Students in the materials class prepared three...Ch. 6 - Students in the materials class prepared three...Ch. 6 - Two batches of cement mortar with properties as...Ch. 6 - What are the five primary types and functions of...Ch. 6 - Why isnt pozzolan used with Type III cement?Ch. 6 - What type of cement would you use in each of the...Ch. 6 - In order to evaluate the suitability of nonpotable...Ch. 6 - Three standard mortar cubes were made using...Ch. 6 - Four standard mortar cubes were made using...Ch. 6 - Discuss the problem of disposal of waste water...Ch. 6 - State five types of admixtures and discuss their...Ch. 6 - Prob. 6.27QPCh. 6 - Under what condition is an air-entraining agent...Ch. 6 - If a water reducer is added to the concrete mix...Ch. 6 - Prob. 6.30QPCh. 6 - A concrete mix includes the following ingredients...Ch. 6 - The results of an experiment to evaluate the...Ch. 6 - The results of a laboratory experiment to evaluate...Ch. 6 - Referring to Table P6.34, Mix No. 1 was designed...Ch. 6 - Two batches of concrete cylinders were made with...Ch. 6 - Two batches of concrete cylinders were made with...Ch. 6 - What is the source of fly ash? Why is fly ash...Ch. 6 - A materials engineer is working in a research...Ch. 6 - A materials engineer is working in a research...
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