Podcast
Questions and Answers
According to Kosmatka, S.H. et al. (2002), which statement accurately describes concrete?
According to Kosmatka, S.H. et al. (2002), which statement accurately describes concrete?
- A mixture of aggregate and paste. (correct)
- Primarily composed of Portland cement.
- A type of naturally occurring sedimentary rock.
- A singular, homogenous material used in construction.
What role does Portland cement paste play in the formation of concrete?
What role does Portland cement paste play in the formation of concrete?
- It acts as a filler to reduce the overall cost of the concrete mix.
- It increases the concrete's resistance to weathering and erosion.
- It binds the aggregates together through a chemical process called hydration. (correct)
- It provides the primary structural strength of the concrete.
In concrete, what is the primary distinction between 'fine aggregates' and 'course aggregates'?
In concrete, what is the primary distinction between 'fine aggregates' and 'course aggregates'?
- Fine aggregates are used in PCC, while course aggregates are used in RCC.
- Fine aggregates are natural, while course aggregates are synthetic.
- Fine aggregates pass through a No. 16 sieve, while course aggregates are retained. (correct)
- Fine aggregates contribute to the color, while course aggregates affect the texture.
Which of the following best illustrates a common application of concrete?
Which of the following best illustrates a common application of concrete?
A construction engineer notices the concrete mix is setting too quickly in warm weather. Which admixture would be most suitable to counteract this issue?
A construction engineer notices the concrete mix is setting too quickly in warm weather. Which admixture would be most suitable to counteract this issue?
Superplasticizers are added to concrete mixtures to achieve what?
Superplasticizers are added to concrete mixtures to achieve what?
What is the primary purpose of using accelerators as a concrete admixture?
What is the primary purpose of using accelerators as a concrete admixture?
In the context of concrete, what does 'curing' primarily involve?
In the context of concrete, what does 'curing' primarily involve?
The duration of concrete curing depends on multiple factors. Which factor is NOT a key consideration when determining curing time?
The duration of concrete curing depends on multiple factors. Which factor is NOT a key consideration when determining curing time?
For smaller concrete work performed in a laboratory setting, which curing method is most suitable?
For smaller concrete work performed in a laboratory setting, which curing method is most suitable?
Under what condition is spraying and fogging the preferred technique for curing concrete?
Under what condition is spraying and fogging the preferred technique for curing concrete?
Which of the following statements correctly differentiates between Plain Cement Concrete (PCC) and Reinforced Cement Concrete (RCC)?
Which of the following statements correctly differentiates between Plain Cement Concrete (PCC) and Reinforced Cement Concrete (RCC)?
What is the impact of using too much water in a concrete mix?
What is the impact of using too much water in a concrete mix?
Which characteristic is most indicative of 'fresh concrete'?
Which characteristic is most indicative of 'fresh concrete'?
For fresh concrete to be considered acceptable, what primary attribute should it possess?
For fresh concrete to be considered acceptable, what primary attribute should it possess?
Flashcards
What is concrete?
What is concrete?
Concrete is a mixture of aggregate and paste.
Where is concrete used?
Where is concrete used?
Bridges, buildings, and pavements.
What are concrete admixtures?
What are concrete admixtures?
Concrete admixtures reduce water, speed setting, or slow chemical processes.
What do super plasticizers do?
What do super plasticizers do?
Signup and view all the flashcards
What do accelerators do?
What do accelerators do?
Signup and view all the flashcards
What do retarders do?
What do retarders do?
Signup and view all the flashcards
How is concrete curing performed?
How is concrete curing performed?
Signup and view all the flashcards
What concrete curing methods are there?
What concrete curing methods are there?
Signup and view all the flashcards
Types of concrete?
Types of concrete?
Signup and view all the flashcards
What are the properties of PCC?
What are the properties of PCC?
Signup and view all the flashcards
What is RCC composed of?
What is RCC composed of?
Signup and view all the flashcards
What affects concrete quality?
What affects concrete quality?
Signup and view all the flashcards
What happens with too much water?
What happens with too much water?
Signup and view all the flashcards
What is the state of freshly mixed concrete?
What is the state of freshly mixed concrete?
Signup and view all the flashcards
Fresh concrete vs hardened concrete
Fresh concrete vs hardened concrete
Signup and view all the flashcards
Study Notes
- Course material for CIV 1202
- The document is about Fundamentals of Concrete Part 1
Learning Outcomes
- Describe concrete and its possible applications
- Explain concrete admixtures and their purpose
- Briefly describe the role of concrete curing and the method
- Identify the types of concrete and their difference
- Briefly describe how water content impacts the quality of concrete
- Describe the difference between fresh and hardened concrete
Concrete Basics
- According to S,H, Kosmatka, et al. (2002), concrete is "a mixture of two components: aggregate and paste"
- Paste is made of Portland cement which binds aggregates (gravel and sand) to form a stone like mass
- This process is called hydration
- Aggregates can be coarse or fine
- Fine aggregates have particle sizes up to 9.5 mm
- Coarse aggregates are retained in the No. 16 sieve and are up to 150 mm in size
- Paste is made of cementitious material, water and air
- Portland cement is the most common type of cement used
Applications of Concrete
- Concrete is used for bridges
- Concrete is used for buildings (high rise and low rise)
- Concrete is used for pavements, parking lots, gas stations, and roadways
Concrete Admixtures
- Superplasticizers will reduce the water content by 12 to 30%, and improve workability and compaction
- The improved properties of concrete due to superplasticizers increases its overall strength
- Accelerators speed up the setting time of concrete and increase early strength development
- Retarders slow down the chemical process so that concrete remains plastic and workable for a long time
- Air-entraining agents are a type of concrete admixture that improves the durability of concrete
- Concrete gains strength overtime, once kept in a moist environment
- About 90% of its strength will be gained the first 28 days
Concrete Curing
- Curing can be performed in a laboratory or at the construction site immediately after the concrete is placed
- Length of curing time depends on the mixture proportions
- Length of curing time depends on specified strength
- Length of curing time depends on weather conditions
- Length of curing time depends on future exposure conditions
- Curing maintains mixing water in concrete during the hardening process
- Ponding and immersion is a method used for smaller work
- Immersion is mainly used in a lab setting
- Fogging is used to raise the humidity by spraying a mist of water to maintain moisture content
- Forms protect against moisture loss and are made of wood, they are kept moist during hot and dry weather
- Covering concrete with impervious paper or plastic sheets to reduce the loss of mixing water from the surface
Types of Concrete
- Plain Cement Concrete (PCC) and Reinforced Cement Concrete (RCC)
- PCC is a concrete mixture without reinforcement
- PCC is strong in compression but week in tension
- PCC is commonly used for paving and flooring
- RCC consists of cement, sand, aggregate, and reinforcement
- In RCC tensile strength is increased
Quality of Concrete
- Influenced by the bond between the paste and the aggregate
- Quality of hardened concrete is influenced by the amount of water vs. cement ratio
- Too much water can dilute the cement paste
- Too little water results in a stiffer mixture
- Freshly mixed concrete should be "plastic" or semifluid and capable of being molded by hand
Fresh vs Hardened Concrete
- Fresh concrete is in the stage where it can be molded in its plastic stage
- Fresh concrete is known as "green concrete"
- For fresh concrete to be acceptable it has to be easily mixed and transported
- For fresh concrete to be acceptable its consistency should be such that it can completely fill the forms for which it is designed
- For fresh concrete to be acceptable it has to have good finishing characteristics
- For fresh concrete to be acceptable it has to have the ability to be compacted without excessive loss of energy
- For fresh concrete to be acceptable it has to be uniform throughout each batch
- Hardened concrete is in the stage where the concrete is fully cured
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
