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Concrete and Cement Fundamentals
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Concrete and Cement Fundamentals
Concrete and Cement Fundamentals
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1
Question
What type of rock is basalt classified as?
Answer
Basalt is classified as an Extrusive Igneous rock.
2
Question
Which property of the same aggregate has the lowest value?
Answer
The lowest value property of the same aggregate is the Dry bulk unit weight.
3
Question
What are the four main chemical compounds present in Portland cement?
Answer
The four main chemical compounds present in Portland cement are: 1. Tricalcium silicate (C3S) 2. Dicalcium silicate (C2S) 3. Tricalcium aluminate (C3A) 4. Tetra-calcium aluminoferrite (C4AF).
4
Question
Which compound should be reduced in amount in order to reduce sulfate attack in concrete?
Answer
The compound that should be reduced to minimize sulfate attack in concrete is Tricalcium Aluminate (C3A).
5
Question
What is the most important factor affecting the slump of fresh concrete?
Answer
The most important factor affecting the slump of fresh concrete is Water Content.
6
Question
What is the most important factor affecting the strength of hardened concrete?
Answer
The most important factor affecting the strength of hardened concrete is the Water to Cement Ratio.
7
Question
Which type of Portland cement is recommended for use in a high sulfate environment?
Answer
Type V Portland cement is recommended for use in a high sulfate environment.
8
Question
What is a possible effect of using seawater as mixing water in concrete?
Answer
Using seawater as mixing water in concrete can lead to a reduction in the ultimate strength of the concrete.
9
Question
What is the effect of permeability on hardened concrete?
Answer
Lower permeability in hardened concrete reduces the risk of durability issues and increases the concrete's resistance to aggressive chemicals.
10
Question
What is the effect of particle shape and surface texture of aggregate on the properties of concrete?
Answer
Rough textured and angular aggregates give higher strength to the concrete at the same water-cement (wc) ratio.
11
Question
What is the approximate relationship between the tensile strength and the compressive strength of concrete?
Answer
Tensile strength is about 10% of compressive strength.
12
Question
How is limestone classified in terms of rock types?
Answer
Limestone is classified as a Sedimentary Rock.
13
Question
Which property of the same aggregate would typically have the highest value?
Answer
SSD bulk density has the highest value among the properties of the same aggregate.
14
Question
What are the main chemical compounds present in Portland cement, and which one is important for early strength in concrete?
Answer
The four main chemical compounds in Portland cement are C3S (Tricalcium Silicate), C2S (Dicalcium Silicate), C3A (Tricalcium Aluminate), and C4AF (Tetracalcium Aluminoferrite). C3S is important for early strength in concrete.
15
Question
What is not an effective measure for hot-weather concreting?
Answer
Spray concrete with icy water is not an effective measure to be taken in hot-weather concreting.
16
Question
What type of Portland cement would you generally use in construction?
Answer
You would use type I Portland cement for general construction, type II for structures that require moderate resistance to sulfate attacks, type III for high early strength, and type IV for structures with low heat of hydration.
17
Question
What is Type IV concrete used for?
Answer
Type IV concrete is used in structures that require low heat of hydration, such as in large mass concrete elements like dams.
18
Question
Which one of the following is not an effective measure to be taken in cold-weather concreting?
Answer
Using antifreeze in mixing water is not an effective measure for cold-weather concreting.
19
Question
What is a typical specific gravity of Portland cement?
Answer
The typical specific gravity of Portland cement is 3.15.
20
Question
What is the main purpose of a control joint in a concrete structure?
Answer
The main purpose of a control joint in a concrete structure is to allow concrete to crack at the joint rather than randomly.
21
Question
What is the correct sequence of steps in finishing a concrete slab?
Answer
The correct sequence of steps in finishing a concrete slab is: Strikeoff, Bullfloating, Floating, Troweling.
22
Question
Which statement is not true concerning the effects of permeability of hardened concrete?
Answer
The statement that lower permeability reduces the strength of concrete is not true.
23
Question
What is a typical density of concrete made with Florida limestone?
Answer
A typical density of concrete made with Florida limestone is 140 pounds per cubic foot (pcf).
24
Question
How is the result of the LA Abrasion test reported?
Answer
The result of the LA Abrasion test is reported in a percentage of loss.
25
Question
How is the result of the Organic Impurity test reported?
Answer
The result of the Organic Impurity test is reported in degrees Fahrenheit (deg. F) or degrees Celsius (deg. C).
26
Question
What is the purpose of the Wagner Turbidimeter test?
Answer
The purpose of the Wagner Turbidimeter test is to measure the fineness of cement.
27
Question
What is a desirable test for assessing concrete durability?
Answer
A desirable test for assessing concrete durability is the Rapid Chloride Permeability Test.
28
Question
What is the result from the Aggregate Soundness Test?
Answer
A soundness loss of less than 12.
29
Question
How is limestone classified?
Answer
Limestone is classified as a Sedimentary Rock.
30
Question
Which property of the same aggregate would have the highest value?
Answer
SSD (Saturated Surface-Dry) bulk density.