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Questions and Answers
What compound prevents flash setting?
What compound prevents flash setting?
What are the characteristics of pozzolan?
What are the characteristics of pozzolan?
Fineness of cement affects the following:
Fineness of cement affects the following:
What do we call the ability of cement not to undergo large change in volume during hydration?
What do we call the ability of cement not to undergo large change in volume during hydration?
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What is the basis of the strength of cement?
What is the basis of the strength of cement?
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What is the usual liquid used in determining the specific gravity of cement?
What is the usual liquid used in determining the specific gravity of cement?
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The term hydration refers to the chemical reaction between cement, water, and aggregates.
The term hydration refers to the chemical reaction between cement, water, and aggregates.
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What are the compounds that contribute much to the hydration of cement?
What are the compounds that contribute much to the hydration of cement?
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What is the standard specific gravity of cement?
What is the standard specific gravity of cement?
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What are the inert and inexpensive material that occupies large percentage volume of concrete?
What are the inert and inexpensive material that occupies large percentage volume of concrete?
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If the rebare spacing is 1 inch (25.44mm), what is the aggregate size (mm) that will produce the most economical concrete?
If the rebare spacing is 1 inch (25.44mm), what is the aggregate size (mm) that will produce the most economical concrete?
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What are affected by the shape of aggregates?
What are affected by the shape of aggregates?
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If the percentage absorption of aggregate is 5%, what is its specific gravity at oven dried condition if the specific gravity at SSD condition is 2.35?
If the percentage absorption of aggregate is 5%, what is its specific gravity at oven dried condition if the specific gravity at SSD condition is 2.35?
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Which one is an ideal texture of aggregates for concreting job?
Which one is an ideal texture of aggregates for concreting job?
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Which one is the desired grain size distribution or grading of aggregates to produce good concrete?
Which one is the desired grain size distribution or grading of aggregates to produce good concrete?
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What is the average diameter of aggregates if the fineness modulus is 3.0?
What is the average diameter of aggregates if the fineness modulus is 3.0?
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Among the choices, which are the physical properties of aggregates?
Among the choices, which are the physical properties of aggregates?
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What admixture do we use to advance the time that a structure can be made in service?
What admixture do we use to advance the time that a structure can be made in service?
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Accelerator can be used with set retarder in concrete mix.
Accelerator can be used with set retarder in concrete mix.
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Which admixtures can be used to produce high strength concrete?
Which admixtures can be used to produce high strength concrete?
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Which are the effects of a set retarder in a concrete mix?
Which are the effects of a set retarder in a concrete mix?
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What are the effects of plasticizer in a concrete mix?
What are the effects of plasticizer in a concrete mix?
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What should be the acceptable quality of water for a concrete mix?
What should be the acceptable quality of water for a concrete mix?
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Is the strength of hard concrete affected by the workability of fresh concrete?
Is the strength of hard concrete affected by the workability of fresh concrete?
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What are the purposes of vibrating fresh concrete?
What are the purposes of vibrating fresh concrete?
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What are the causes of shrinkage in concrete?
What are the causes of shrinkage in concrete?
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What are the advantages of ready-mix concrete?
What are the advantages of ready-mix concrete?
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What are the different methods in determining the air content of fresh concrete?
What are the different methods in determining the air content of fresh concrete?
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Choose from the list below which ones are the purpose of curing?
Choose from the list below which ones are the purpose of curing?
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What is the term used in coating the inner sides of the mixer with an initial amount to of mortar or cement paste?
What is the term used in coating the inner sides of the mixer with an initial amount to of mortar or cement paste?
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What is another term for shotcrete?
What is another term for shotcrete?
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Which one below is the acceptable diameter of pipe for pumping concrete if the maximum aggregate size is 19 mm?
Which one below is the acceptable diameter of pipe for pumping concrete if the maximum aggregate size is 19 mm?
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A harsh concrete is a fresh concrete that is difficult to mix.
A harsh concrete is a fresh concrete that is difficult to mix.
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What is the term used for fresh concrete pumped underpressure?
What is the term used for fresh concrete pumped underpressure?
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Among those listed below, which are the measurable properties of fresh concrete?
Among those listed below, which are the measurable properties of fresh concrete?
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What are the possible causes of segregation of fresh concrete?
What are the possible causes of segregation of fresh concrete?
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What is the property of fresh concrete defining the time required to reach the specified vale of resistance to penetration?
What is the property of fresh concrete defining the time required to reach the specified vale of resistance to penetration?
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What are the factors affecting workability of fresh concrete?
What are the factors affecting workability of fresh concrete?
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What is the method used to deposit concrete under water?
What is the method used to deposit concrete under water?
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What are the acceptable sizes of specimen for compression test of concrete?
What are the acceptable sizes of specimen for compression test of concrete?
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What contributes to the strength of concrete?
What contributes to the strength of concrete?
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What are some of the mechanical properties of hard concrete?
What are some of the mechanical properties of hard concrete?
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Whach one is the acceptable and realistic value of Poisson's ratio of concrete?
Whach one is the acceptable and realistic value of Poisson's ratio of concrete?
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Whate is the assumed density of normal weight concrete in kg/cum?
Whate is the assumed density of normal weight concrete in kg/cum?
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The concrete stress-strain curve is considered to be elastic up to what percentage of f 'c?
The concrete stress-strain curve is considered to be elastic up to what percentage of f 'c?
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If the compressive strength of normal weight concrete is 28 MPa, which one is the value of the modulus of elasticity, Ec?
If the compressive strength of normal weight concrete is 28 MPa, which one is the value of the modulus of elasticity, Ec?
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What is the term used for the long-term deformation of concrete due to application of sustained load?
What is the term used for the long-term deformation of concrete due to application of sustained load?
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The compressive strength of concrete used in structural design is obtained on how many days after mixing concrete?
The compressive strength of concrete used in structural design is obtained on how many days after mixing concrete?
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If the compressive strength(f'c) of concrete is 21 MPa, what is the modulus of rupture of concrete (in MPa) according to Code?
If the compressive strength(f'c) of concrete is 21 MPa, what is the modulus of rupture of concrete (in MPa) according to Code?
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The shape of standard specimen used for determining the compressive strength and split-tensile strength of concrete?
The shape of standard specimen used for determining the compressive strength and split-tensile strength of concrete?
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Study Notes
Concrete Materials and Properties
- Compounds Preventing Flash Setting: Gypsum, Calcium silicate hydrate, Dicalcium silicate, Calcium hydroxide
- Pozzolan Characteristics: Reacts with calcium hydroxide, Blended cement, A natural cementitious material, Siliceous/aluminous material.
- Cement Fineness Effects: Impacts amount of clinker produced, Rate of hydration, Cost of heating, and Gypsum requirement.
- Hydration Ability: Exothermic, Fineness, Shrinkage, and Soundness are the properties of cement that affect the ability of cement to undergo large volume change during hydration.
- Cement Strength Basis: Based on standards like ASTM C190, Testing using concrete cylindrical tests, ASTM C348, and ASTM C109.
- Cement Specific Gravity Determination: Typically using water as a reference liquid.
Aggregate Properties
- Standard Specific Gravity of Cement: 3.15
- Inert and Inexpensive Concrete Material: Aggregates
- Aggregate Size for Economy: Variations in aggregate size influence economy. (ex: 3/4", 1", 1/2", 3/8")
- Aggregate Shape Effects: Impacts properties like water requirement, void ratio, and bond area. Influences durability.
- Aggregate Absorption and Specific Gravity: The percentage absorption (e.g., 5%) of aggregate affects its specific gravity at oven-dry conditions (e.g., 2.35 as SSD). Ideal concrete uses 2.24.
- Ideal Aggregate Texture: Smooth is preferable. Rough, Honeycombed, and Glassy textures are not the best choices.
- Aggregate Grading: Well-graded aggregates are optimal for concrete. Flat graded, and Uniformly graded are not ideal.
- Average Aggregates Diameter by Fineness Modulus: 0.6 using a fineness modulus of 3.0.
- Mechanical Aggregate Properties: Bond, Strength, Toughness, and Durability are considered the key mechanical properties.
- Aggregates Physical properties: Specific gravity, Absorption, Grading, and Soundness are considered the key physical properties.
Admixtures
- Set Retarders/Accelerators: Admixtures that manipulate setting time in concrete. Accelerators can be used with set retarders.
- High Strength Concrete Admixtures: Plasticizer, air-entraining admixture, accelerator, and silica fume to improve properties.
- Retarder Effects: Reduce early strength, Improve workability, and Lessen formation of cold joints.
- Plasticizers Effects: Increase workability, Increase early strength, Improved waterproof concrete. Increase water content.
- Acceptable Water Quality: Purified water, water free from impurities, Rainwater, and potable water are preferable for concreting.
- Fresh Concrete Vibration: Vibrating fresh concrete ensures proper filling and provides better workability and removes air entrainment.
- Purpose of Curing: Improve concrete surface, Remove impurities from concrete, prevent water evaporation, enhanced hydration of concrete.
- Concrete Coating/Buttering: Applying an initial layer of mortar or cement paste to the inner sides of mixers for uniform distribution. "Buttering" is another term.
Concrete Testing and Properties
- Acceptable Poisson's Ratio: 0.1, 0.2, 0.3, 0.4
- Normal Weight Concrete Density: 2400 kg/m³.
- Elastic Limit Percentage of fc': The concrete stress-strain curve is considered elastic up to around 50% of fc'.
- Modulus of Elasticity (Ec): Related to the compressive strength (fc') of normal weight concrete; it is important to understand the relationship between compressive strength and modulus of elasticity. Typical values are: 20,000, 25,800, 21,538, 24,870 MPa.
- Creep Definition: Long-term deformation of concrete caused by sustained load.
- Compressive Strength Days: Compressive strength of concrete for structural design is commonly determined after 28 days.
- Modulus of Rupture (for 21 MPa fc'): 2.84 MPa.
- Concrete Specimen Shapes: Cube, Prism, Beam, Cylinder are standard shapes used for strength testing.
Fresh Concrete Properties
- Pumpcrete/Batched Concrete: Types of concrete.
- Fresh Concrete Measurable Properties: Workability, Bleeding, Segregation, Air Content.
- Causes of Segregation: Gap grading (uneven grain size distribution), Improper vibration, Incorrect transportation, and use of river gravel.
- Setting Time: Time taken to achieve specific resistance to penetration.
- Workability Affecting Factors: Water content, Aggregate grading, Maximum size of aggregates, and Air content and density.
- Concrete Under Water Deposition Method: Tremie.
- Acceptable Specimen Sizes: 100mm x 200mm cylinders, 6” cubes, 50mm cube, and 6” x 12” cylinders.
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Description
Test your knowledge on the essential properties and behaviors of concrete materials. This quiz covers topics like compounds that prevent flash setting, the characteristics of pozzolans, cement fineness effects, and the basis of cement strength testing. Perfect for students in civil engineering or construction-related courses.
