38 Questions
What is the percentage weight of soil retained on the 4.75 sieve?
9.71%
In the combined grading of fine and coarse aggregate, what properties of concrete can be better controlled?
Workability and Shrinkage
What does the reduction of voids achieve in concrete when different aggregate sizes are combined?
Decreased Void-Content
The Fine Module (FM) value falls within which range for medium aggregate according to the example provided?
2.5 – 2.8
Why is it important to determine the absorption and surface moisture of aggregates in concrete?
To control water content and batch weights
What is the purpose of limestone sweetening in concrete production?
To enhance the ASR resistance by replacing 30% of the reactive aggregate with limestone
Which factor does NOT influence the Alkali-Carbonate Reaction (ACR)?
Moisture content in concrete
Which testing method is NOT used for Alkali-Carbonate Reaction (ACR) assessment?
Moisture absorption test
What is the main effect of lithium-based admixtures in concrete?
To reduce ASR expansion
How does spraying a 30% LiNO3 solution with a tanker truck contribute to concrete production?
It enhances ASR resistance
Why is particle size important in concrete?
It influences the surface area available for cement paste interaction
How does the particle size affect the surface area in concrete?
Bigger particles result in higher surface area
What is the effect of larger coarse aggregate on cement requirement in concrete?
Less cement is required
How does larger coarse aggregate influence water requirement in concrete mixtures?
Less water is required
What does Fineness Modulus (FM) measure in aggregates?
Particle size distribution of aggregates
What is the maximum percentage of particles that should pass through the 4.75 mm sieve according to ASTM C33 grading limits?
95%
What is the purpose of the Nominal Maximum Size of an aggregate?
It determines the maximum size of aggregate to ensure proper concrete properties.
What does it mean if an aggregate has a percentage of retained aggregate at 0% on a sieve analysis?
All particles passed through the sieve.
How does the Nominal Maximum Size relate to the dimensions of forms in a construction project?
It should not exceed 1/5 the narrowest dimension between sides of forms.
Why is Alkali-Silica Reaction (ASR) more concerning than Alkali-Carbonate Reaction (ACR)?
ASR aggregates have a more common occurrence of reactive silica minerals.
What does it mean in aggregate grading if the percentage passing a certain sieve is below the ASTM lower limit?
The aggregate is too fine.
Which visual symptom is associated with Alkali-Silica Reaction (ASR)?
Fragments breaking out of the surface (popouts)
What is the mechanism behind Alkali-Silica Reaction (ASR)?
Alkali hydroxide + Reactive silica + Moisture -> Alkali Silica Gel + Alkali Silica gel filling microcracks
Which testing method is used for detecting Alkali-Silica Reaction (ASR)?
Concrete Prism Test (ASTM C 1293)
What condition must be present for Alkali-Silica Reaction (ASR) to occur?
Alkali + Reactive silica + Moisture
What is the main cause of D-cracking in concrete pavements?
Failure of carbonate coarse aggregate
Which of the following describes a popout in concrete?
Breaking away of a small fragment of concrete due to internal pressure
What can potentially make aggregates harmful if they react chemically with concrete?
Interfering with the normal hydration of cement
What is Alkali-Aggregate Reactivity (AAR) defined as?
A chemical reaction between aggregates and alkali hydroxides in concrete
What does combined grading aim to achieve in aggregates?
Reduction of voids in concrete
What is the particle size range for fine aggregate, according to ASTM Sieve Sizes?
150 μm to 9.5 mm
Which type of aggregate is Rocks and minerals classified as?
Coarse aggregate
What does grading of aggregate refer to?
Particle size distribution
What type of sieve analysis is used for determining the grading of aggregate?
Wire mesh sieves with square openings
Which sieve sizes are used for determining the particle size distribution of fine aggregate?
7 standard sieves from 150 μm to 9.5 mm
Which type of aggregate is Crushed blast-furnace slag classified as?
Heavy aggregate
What do the curves on the particle size distribution curve indicate?
Particle size limits specified in ASTM C 33
What does the square grid in sieve analysis allow through?
Smaller particles
Test your knowledge on issues affecting concrete pavements, including moisture adjustment, aggregate problems, D-cracking, and harmful reactive substances. Identify causes of cracking in concrete pavements and learn about the impact of aggregate moisture content on pavement durability.
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