1 Exam Prep – Design and Control of Concrete Mixtures, 14th Edition 1
1 Exam Prep
Design and Control of Concrete Mixtures
Tabs and Highlights
These 1 Exam Prep Tabs are based on the 14th Edition of the Design and Control of Concrete Mixtures,
Kosmatka and Panarese, Portland Cement Association copyright 2008.
Each Tabs sheet has five rows of tabs. Start with the first tab at the first row at the top of the page; proceed
down that row placing the tabs at the locations listed below. Place each tab in your book setting it down one
notch until you get to the bottom of a page. Then start back at the top again. After each Tab, under
"Reason/Highlight" is a brief explanation of the purpose of the tab, and/or items to highlight in the section.
Special Note to our Students: If you are a 1 Exam Prep student, here is how to really get the most from
these 1 Exam Prep Tabs. Follow the above instructions, but before placing the tab, find the tab's topic in the
outline of your appropriate module. Now locate and highlight several items listed in the outline just before
the topic, and just after. See how the topic fits in the outline and how it relates as a concept to the broader
concept spelled out in the outline. If you take a few minutes to do this, when you take the test key words in
the test questions will remind you of where the information is in the manual!
1 Exam Prep Tab Page # Reason/Highlight
Table of Contents iii Table of Contents
Fundamentals of 1 Fundamentals of Concrete
Concrete
Figure 1-1
Aggregate: 60% 75% of volume.
2 Freshly Mixed Concrete: Freshly mixed concrete should be plastic or
semi fluid
3 Workability: The ease of placing, consolidating, and finishing freshly
mixed concrete and the degree to which it resists segregation is called
workability.
4 Hydration, Setting Time, and Hardening: chemical reaction of
cement and water.
5 Hardened Concrete
6 Drying Rate of Concrete
Strength 7 Strength: Inversely proportional to water/cement ratio.
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8 Figure 1-17: Strength verses water - cement (W/C) ratio.
Density: Conventional concrete, normally used in pavements,
buildings, and other structures, has a density in the range of 2200 to
2400.
9 Permeability and Water tightness: Concrete used in water-retaining
structures or exposed to weather or other severe exposure conditions
must be virtually … Generally, the same properties of concrete that
make it less permeable also make it more watertight.
Leakage Rate 10 Figure 1-20: Leakage Rate.
Abrasion Resistance: Floors, pavements, and hydraulic structures …
Strong concrete has more resistance to abrasion than does weak
concrete.
11 Volume Stability and Crack Control: Hardened concrete changes
volume due to changes in temperature …The rate of creep decreases
with time.
12 Two basic causes of cracks in concrete are: (1) – (2).
Joints 12 Joints: control, isolation and construction.
Durability: The durability of concrete mat be defined as the ability of
concrete to resist weathering action …curing practicing determine the
ultimate durability and the life of the concrete.
13 Alkali-Aggregate Reactivity: Alkali-aggregate reactivity is a type of
concrete … aggregates react with the alkali hydroxides in the concrete.
14 Chloride Resistance and Steel Corrosion: Seawater can destroy or
penetrate the film. Once chloride corrosion threshold (about 0.15%
water-soluble chloride by mass cement).
16 For the best defense during external sulfate attack: (1) - 2).
Types of Cement 27 Types of Portland Cement: I, II, III, IV, V.
28 Table 2-2: Types of Cement Required for Concrete Exposed to Sulfates
in Soil or Water
1 Exam Prep – Design and Control of Concrete Mixtures, 14th Edition 3
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30 Air-Entraining Portland Cements: They correspond in composition
to ASTM Types I, II, and II.
White Portland Cements: It is made to conform to the specification s
of ASTM C 150, usually Type I or Type III.
31 Blended Hydraulic Cements: ASTM C 595 recognizes five primary
classes of blended cements as follows … Types IS, IP, P, I (PM), and
I)SM) are general purpose cements.
32 Hydraulic Cements: ASTM C1157 provides six types of hydraulic
cement as follows:
33 Table 2-3: Applications for Commonly Used Cements
Masonry and Mortar Cements: Masonry and mortar cements are
hydraulic cements designed for … They consist of a mixture of
Portland cement or blended hydraulic cement and plasticizing
materials.
35 Plastic Cements: Plastic cement is a hydraulic cement that meets the
requirements of ASRTM C 1328. It is used to make portland cement
based plaster or stucco.
47 Compressive Strength
Heat of Hydration
Figure 2-42: Type cement verses strength
48 Figure 2-43
52 Transportation and Packaging: Cement weight: 94 pounds per bag
Mixing Water 73 Mixing water for Concrete
75 Chloride: The ACI 318 building code limits water soluble chloride ion
content in reinforced concrete to the following percentages by mass of
cement: Prestressed concrete 0.06% - Other reinforced concrete
construction 0.30%.
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76 Seawater: Sewater containing up to 35,000 ppm of dissolved salts is
generally suitable as mixing water for concrete not containing steel.
Aggregates for 79 The fine and coarse aggregates generally occupy 60% to 70% of the
Concrete concrete volume … crushed stone with particles predominately larger
than 5 mm and generally between 9.5 mm and 37.5 mm
83 Fine-Aggregate Grading
Table 5-3: Fine-Aggregate Grading Limits (ASTM C 33/AASHTO M
6)
Coarse-Aggregate Grading: The maximum size of coarse aggregate
used in concrete has a bearing on the economy … The optimum
maximum size of coarse aggregate for higher strength depends on
factors such as relative strength of the cement paste, cement aggregate
bond, and strength of the aggregate particles.
Aggregate 86 Gap-Graded Aggregates: For an aggregate of 19-mmm …
usually the 4.75 mm to 19 mm sizes are omitted.
88 Absorption and Surface Moisture: The moisture conditions of
aggregates are shown in. 5-12. They are designated as: 1-4. n Fig
Moisture size.
Figure 5-12: Moisture conditions of aggregate.
Bulking: Bulking is an increase in total volume of moist fine aggregate
over the same mass dry.
91 Resistance to Acid and Other Corrosive Substances: other
pozzolans, helps keep the corrosive agent from penetrating into the
concrete.
130 Figure 8-2: Percent air verses freeze/thaw cycles.
132 Resistance to deicers and salts.
Admixtures 105 Admixtures for Concrete: Admixtures can be classified by function as
follows: 1-11.
The major reasons for using admixtures are: 1-4.
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Figure 6-1: Concrete Admixtures
Trial mixtures should be made with the admixture …anticipated on the
job.
106 Table 6-1: Concrete Admixtures by Classification
113-114 Accelerating admixtures: Calcium chloride: 2% by weight of cement
114 Applications where calcium chloride should be used with caution: 1-8.
Bonding 116 Bonding Admixtures & Bonding Agents
125 Figure 7-7: Polypropylene fibers are produced either as fine fibrils with
rectangular cross section.
Air-Entrained 129 Air-Entrained Concrete
Concrete
Deicer-Scaling Resistance
134 Air Drying: The resistance of air-entrained concrete to freeze-thaw
cycles and deicers is greatly increased by an air drying period after
initial moist curing.
Strength: When the air content is maintained constant … however,
necessitate some increase in cement content.
136 Workability: Air entrained improves the workability of concrete …
Workability of mixes with angular and poorly graded aggregates is
similarly improved.
Factors Affecting Air Content
Cement: As cement content increases, the air content decreases for a
set dosage of air-entraining admixture per unit of cement within the
normal range of cement within the normal range of cement contents.
138 Figure 8-16
Mixing Water and Slump
141 Slump and Vibration
1 Exam Prep – Design and Control of Concrete Mixtures, 14th Edition 6
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142 Concrete Temperature: Temperature of the concrete affects air
content, as shown in Fig. 8-19. Less air entrained as the temperature of
the concrete increases.
Air Contents 145 Recommended Air Contents
Proportioning 149 Designing and Proportioning Normal Concrete Mixtures: A
Mixtures properly proportioned concrete mix should possess these qualities: 1-3.
Water-Cementing Materials Ratio and Strength Relationship:
Within the normal range of strengths used in concrete construction, the
compressive strength is inversely related to the water cement ratio or
water-cementing materials ratio.
150 Table 9-1 Maximum water-cement (W/C) ratio
Water 151 Table 9-3 Maximum water-cement (WIC) ratio verses strength
153 Slump
154 Table 9-5 Water verses aggregate size verses slump.
155 Table 9-6 Recommended slumps
157 Proportioning: proportioning methods have evolved from the arbitrary
volumetric method (1:2:3- cement: sand: coarse aggregate) of the early
1900s.
161 FineAggregate Content: Volume computations are as follows: (know
all formulas).
164 Trial Batch: At this stage, the estimated batch weights should be
checked … of concrete or 2/27 cu yd. (know formulas).
173 Fine Aggregate Content: Volumetric computations are as follows:
(know formulas)
Concrete for 174 Concrete for Small Jobs
Small Jobs
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Batching, Mixing 179 Batching, Mixing, Transporting and Handling Concrete
Moving Concrete
Batching: Specifications generally require that materials be measured
for individual batches with the following percentages of accuracy:
180 Mixing Concrete: Maximum allowable difference to evaluate mixing
uniformity within a batch of ready mixed concrete as given in ASTM C
94.
Stationary Mixing: Careful attention should be paid to the required
mixing time … provided all of the water is added before one-fourth of
the mixing has elapsed.
Under usual conditions, up to about 10% of the mixing water should be
placed in the drum before the solid materials are added.
If retarding or water-reducing admixtures are used … last three-fourths
of the mixing cycle, whichever occurs first.
Ready Mixed Concrete: Ready mixed concrete is proportioned and
mixed off the project site and is delivered to the construction area in a
freshly mixed and unhardened state. It can be manufactured by any of
the following methods: 1-3.
ASTM C 94 notes that when a truck mixer is used for complete mixing
… after 100 should be at a rate of rotation designated by the
manufacturer as a agitating speed.
183 Transporting and handling Concrete
Delays
Early Stiffening and Drying Out: Concrete is kept agitated generally
can be placed and compacted within 1 ½ hours after mixing unless hot
concrete temperatures or high cement contents speed up hydration
excessively.
184 Segregation
Table 10-1
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188 Work At and Below Ground Level: Possibly the concrete can be
chuted directly from the truck mixer to the point needed …Long chutes
over 6 meters, or those not meeting slope standards must discharge into
a hopper before distribution to point of need.
Placing and 191 Placing and Finishing Concrete
Finishing
192 Depositing the Concrete
Vibration 195 Vibration: Vibration, either internal or external, is the most widely
used method for consolidating concrete.
Table 11-1 shows the range of characteristics and applications for
internal vibrators for various applications.
196 Table 11-1: Range of Characteristics, Performance, and Applications of
Internal Vibrators. (Note Group 5).
199 Subgrade Preparation
200 Forms: The forms should be straight and free from warping and have
sufficient strength to resist concrete pressure without bulging. They
should be strong enough to support any mechanical placing and
finishing equipment used.
202 Any finishing operation performed on the surface of a concrete slab
while bleed water is present can cause crazing, dusting, or scaling.
Floating: The purpose of floating is threefold: (1) – (3).
Hand floats are made of fiberglass … more readily over the concrete
surface.
206 Making Joints in Floors and Walls
Isolation Joints: can be as thin as 6 mm or less, but 13-mm material is
commonly used.
1 Exam Prep – Design and Control of Concrete Mixtures, 14th Edition 9
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Contraction Joints: Contraction joints, whether sawed, grooved, or
preformed, should extend into the slab to a depth of at least ¼ the slab
thickness.
206 Figure 11-27: Contraction joints provide …
208 Table 11-2: Spacing of Contraction Joints
Figure 11-29
210 Unjoined Floors: Three unjoined floor methods are suggested: Note
number 3
Form Removal 210-211 Removing Forms: In any case, shoring should not be removed until
the concrete is strong enough ….Advice on reshoring is provided by
ACI Committee 347.
Patching, Cleaning, and Finishing: After forms are removed, all
bulges … cut back to a depth of 13 mmm from the concrete surface.
211 Holes, Defects, Overlays: The mortar should be tamped into place in
layers about 13 mm thick.
The minimum thickness for most patches and overlays us 20 mm.
Some structures, like bridge decks, should have a minimum repair
thickness of 40 mm (1 ½).
Shallow patches can be filled with a dry-pack mortar … 13 mm thick,
with each layer given a scratch finish to improve bond with subsequent
layer.
Figure 11-33: Patch Installation
213 Finishing Formed Surfaces: These surfaces are divided into two
general classes: smooth an textured or patterned.
Curing 219 Curing is the maintenance of a satisfactory moisture content … so that
the desired properties may develop.
Figure 12-2. Curing time verses strength
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220 Curing Methods and Materials: Concrete can be kept moist by three
curing methods: 1-3. (Special attention to number 2)
221 Wet Coverings:
222 Alternate cycles of wetting and drying, during the early curing period
may cause crazing of the surface.
223 Figure 12-8: Luquid membrane-forming curing compounds …
225-226 Curing Period and Temperature: Ambient 40˚F minimum for 7 days.
226 Figure 12-11
Hot Weather 229 Hot Weather Concreting
Concrete
230 Effects of High Concrete Temperatures: As shown in Fig 13-2, if
the temperature of freshly mixed concrete is increased from 10 to
38 .
Figure 13-2. Water verses temperature (3" slump).
231 Cooling Concrete Materials: The aggregates and mixing water should
be kept as cool as practicable … after mixing than other ingredients.
232 Cooling the mix water temperature … more than about 4.5 C by
cooling the water alone.
To lower the temperature of concrete 0.5 C requires only a 0.8 C to
1.1 C reduction in temperature of the coarse aggregate.
234 Cement temperature has only a minor effect on the temperature of
freshly mixed concrete … temperature change of 5 C generally will
change the concrete temperature by only 0.5 C.
235 Plastic Shrinkage Cracking: The following conditions, singly or
collectively, increase evaporation of surface moisture and increase the
possibility of plastic shrinkage cracking: 1-4.
The crack length is generally 50 to 1000 mm in length and they are
usually spaced … with certainty when plastic shrinkage will occur.
1 Exam Prep – Design and Control of Concrete Mixtures, 14th Edition 11
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236 One or more of the precautions listed below can minimize the
occurrence of plastic shrinkage cracking: 1-5.
237 Fogging the concrete before and after the final finishing is the most
effective way to minimize evaporation and reduce plastic shrinkage
cracking.
Curing and Protection
238 Moist-cured surfaces should dry out slowly after the curing period …
The cracks encompass small concrete areas less than 50 mm in
dimension, forming a chicken-wire like pattern.
Cold-Weather 239 Concrete can be placed safely without damage from freezing …
Concrete Normal concreting practices can be resumed once the ambient
temperature is above 10 C for more than half a day.
242 Special Concrete Mixtures
Concrete Testing 275 Concrete Testing
Classes of Tests: Project specifications may affect (1) – (2).
Tests of aggregates have two major purposes: (1) – (2).
Frequency of Testing: Frequency of testing is a significant factor in
the effectiveness of quality control of concrete.
Strength Test 276 Frequency of Testing: The number of strength tests will be made will
depend on the job specifications … tested provide an early indication of
strength development.
Slump Test 279 Testing Freshly Mixed Concrete: Samples should be obtained and
handled directly in accordance with ASTM C172 … purposes be at
least 28 liter.
Consistency: The test equipment consists of a slump cone … long
with a hemispherically shaped tip.
286 Measured strengths varied up to 25%, depending on the time and type
of conditioning prior to testing.
1 Exam Prep – Design and Control of Concrete Mixtures, 14th Edition 12
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High-Performance 299 High-Performance Concrete
Concrete
300 High-Early Strength Concrete: The time period in which a specified
strength could be achieved may range from a few hours to several days.
Special Types of 315 Structural Light Weight Concrete: 85 to 115 PCF/2500 PSI.
Concrete
Table 18-1: Some Special Types of Concrete
317 Slump
Vibration
318 Insulating and Moderate Strength Lightweight Concretes
- Group I
- Group II
- Group III
319 Workability
325 No-Slump Concrete
326 Roller-Compacted Concrete
Shotcrete 327 Soil-Cement
Shotcrete
Appendix 335 Appendix- Glossary
- Bulking
- Contraction Joint
- Normal weight concrete
- Pozzolan
- Scaling
348 Metric Conversion Factors:
Length: foot to meter
Mass: Pound to kilogram
Index 351 Index