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Questions and Answers
Which type of cement is formed by blending 20-30% pozzolanic material with ordinary Portland cement?
Which type of cement is formed by blending 20-30% pozzolanic material with ordinary Portland cement?
What is the primary waste product used in the manufacture of blast furnace cement?
What is the primary waste product used in the manufacture of blast furnace cement?
What is a characteristic of acid-resistant cement?
What is a characteristic of acid-resistant cement?
Which of the following types of cement requires longer curing periods due to lower early strength?
Which of the following types of cement requires longer curing periods due to lower early strength?
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In colored cement production, what percentage of mineral pigments is typically mixed with ordinary cement?
In colored cement production, what percentage of mineral pigments is typically mixed with ordinary cement?
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What compounds does Portland pozzolana cement react with to form cementitious properties?
What compounds does Portland pozzolana cement react with to form cementitious properties?
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Which type of cement contains additives like sodium fluosilicate to enhance its properties?
Which type of cement contains additives like sodium fluosilicate to enhance its properties?
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Which type of Portland cement has the highest percentage of C3S in its composition?
Which type of Portland cement has the highest percentage of C3S in its composition?
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What temperature range is necessary for the complete dissociation of calcium carbonates during the burning stage?
What temperature range is necessary for the complete dissociation of calcium carbonates during the burning stage?
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Which compound is known as Tricalcium silicate in the composition of Portland cement?
Which compound is known as Tricalcium silicate in the composition of Portland cement?
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What is added to clinker before grinding to produce Portland cement?
What is added to clinker before grinding to produce Portland cement?
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During the wet process of cement manufacture, which step comes after the preparation of slurry?
During the wet process of cement manufacture, which step comes after the preparation of slurry?
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What is the final product called after the burning and calcination of raw materials in cement manufacturing?
What is the final product called after the burning and calcination of raw materials in cement manufacturing?
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Which of the following is a disadvantage of the dry process in cement manufacture?
Which of the following is a disadvantage of the dry process in cement manufacture?
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What type of storage tanks are commonly used for storing cement after its manufacture?
What type of storage tanks are commonly used for storing cement after its manufacture?
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What is the setting time for plaster mixed with sufficient water to form a plastic paste?
What is the setting time for plaster mixed with sufficient water to form a plastic paste?
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What is a key advantage of the wet process for manufacturing cement?
What is a key advantage of the wet process for manufacturing cement?
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What is a characteristic of hard-finish plaster?
What is a characteristic of hard-finish plaster?
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What proportion of plaster and sand is expected to develop 80 percent of the neat strength at corresponding ages?
What proportion of plaster and sand is expected to develop 80 percent of the neat strength at corresponding ages?
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Which material is commonly used to strengthen gypsum plaster boards?
Which material is commonly used to strengthen gypsum plaster boards?
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What is the weight of plaster in fibrous gypsum plaster boards?
What is the weight of plaster in fibrous gypsum plaster boards?
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What should be the minimum compressive strength of non-load bearing gypsum partition blocks on gross area?
What should be the minimum compressive strength of non-load bearing gypsum partition blocks on gross area?
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What defines the pyrocells used in gypsum applications?
What defines the pyrocells used in gypsum applications?
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Which application of gypsum is suitable for filling cracks and holes in wooden surfaces before painting?
Which application of gypsum is suitable for filling cracks and holes in wooden surfaces before painting?
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Which of the following issues can lead to unsound cement?
Which of the following issues can lead to unsound cement?
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What causes flash set in cement?
What causes flash set in cement?
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What does the Le Chatelier test assess in cement?
What does the Le Chatelier test assess in cement?
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During hydration, what primarily affects the early rate of heat evolution in cement?
During hydration, what primarily affects the early rate of heat evolution in cement?
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What is the main property necessary for structural use of hardened cement?
What is the main property necessary for structural use of hardened cement?
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At what stage does the fineness of cement affect the early rate of hydration?
At what stage does the fineness of cement affect the early rate of hydration?
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How can the compressive strength of cement be tested?
How can the compressive strength of cement be tested?
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What component in cement can cause expansion due to slow hydration?
What component in cement can cause expansion due to slow hydration?
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What is the primary component of lime mortar?
What is the primary component of lime mortar?
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Which factor is NOT listed as affecting the properties of mortar?
Which factor is NOT listed as affecting the properties of mortar?
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How does lime-sand mortar compare to cement-sand mortar in terms of workability?
How does lime-sand mortar compare to cement-sand mortar in terms of workability?
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What is a disadvantage of using lime mortar compared to cement mortar?
What is a disadvantage of using lime mortar compared to cement mortar?
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What is a requirement for lime mortar to maintain its properties?
What is a requirement for lime mortar to maintain its properties?
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What is the effect of increasing cement content in cement mortar?
What is the effect of increasing cement content in cement mortar?
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What is the recommended action if the silt layer exceeds 3mm in the silt test?
What is the recommended action if the silt layer exceeds 3mm in the silt test?
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Which type of sand is preferred for preparing mortar?
Which type of sand is preferred for preparing mortar?
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Compo mortar is a combination of which materials?
Compo mortar is a combination of which materials?
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In terms of water tightness, which type of mortar should be used for areas exposed to moisture?
In terms of water tightness, which type of mortar should be used for areas exposed to moisture?
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What should be avoided in the sand used for making mortar?
What should be avoided in the sand used for making mortar?
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Which of the following influences the strength of mortar?
Which of the following influences the strength of mortar?
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What type of sand improves the workability of mortar the most?
What type of sand improves the workability of mortar the most?
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What is the purpose of using fine particles in well-graded sand for mortar?
What is the purpose of using fine particles in well-graded sand for mortar?
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What is the impact of impurities in the water used for mortar preparation?
What is the impact of impurities in the water used for mortar preparation?
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What is a common practice for measuring cement in mortar preparation?
What is a common practice for measuring cement in mortar preparation?
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Study Notes
Introduction to Construction Materials
- Course Title: Construction Materials
- Course Code: CENG 2092
- University: Addis Ababa Science and Technology University
Chapter Two: Binders
- Binders are substances used to bind inorganic and organic components
- Binders create strong, hard, and/or flexible bonds
- Binding action results from chemical reactions during heating
- Water mixing, or air exposure play a key role in the process
Types of Binders
-
Mineral Binders:
- Non-hydraulic binders only harden in the presence of air
- The most common non-hydraulic binder is lime
- Gypsum is also a non-hydraulic binder occurring naturally as a soft crystalline rock.
- Bituminous Binders: (e.g., asphalt)
- Synthetic Binders
Lime
- Lime is one of the oldest known cementing materials
- Found globally in varying degrees of hardness
- Primarily composed of calcium oxide (CaO)
- Pure lime combines with CO2 to form white CaCO3
- Usually found with impurities like CO2, Fe2O3, and MgCO3, affecting its color
- Non-hydraulic, but can be made hydraulic
- Produced by burning limestone (CaCO3)
Lime Production Methods
- Vertical shaft kiln: Raw materials are fed at the top
- Rotary kiln: Rotating cylinder, limestone fed at the upper end, fuel and air at the bottom
Classification of Lime
- Quick Lime (Caustic Lime): Obtained by calcining calcium carbonate
- Hydrated Lime (Slaked Lime): Produced by mixing quicklime with water (slaking)
- Dry hydrate: Dry, fine powder after water addition and heat
- Milk of lime: Milky suspension when mixing with lots of water
- Lime putty: Viscous mass made by mixing with a little excess water
- Hydraulic lime: Prepared by burning impure limestone containing clay. It hardens with water.
Gypsum
- Non-hydraulic binder occurring naturally as a soft crystalline rock
- Occurs naturally as hydrous sulfate of lime (CaSO4⋅2H2O)
- Commonly known as alabaster (pure gypsum)
- Used in the arts and building construction
Gypsum's Properties
- Turns into powder when heated, but becomes hard again on adding water
- Forms interlocking crystals upon water addition
- Building gypsum is made through gypsum processing at 150°C-160°C
- Superior surface finish, incombustible, fire resistant, insect resistance, low energy consumption when burning.
- Poor strength and high creep under load, and unstable in water
- Two types of Gypsum plasters:
- Plaster of Paris: Incomplete dehydration of finely ground gypsum at temperatures below 185°C
- Hard Finish Plaster: Produced by burning at a higher temperature, treated with certain solutions(Alum) to become very hard
- Uses in Gypsum Wall Plasters: strength, proportions, wood fibers
Portland Cement
- First patented in 1824
- Named after the Isle of Portland limestone.
- Found in the English Channel.
- The four main steps are the treatment of raw materials, burning the dry mix, grinding the clinker and packaging and storage
- Raw materials include calcium, silica, alumina and iron.
Portland Cement Production Methods
- Dry process: Dry materials are proportioned, milled/ground and fed into the kiln
- Wet process: Water is added to the raw materials, milled into a slurry form, and then ground and blended into clinker form
- Major Steps:
- Treatment of raw materials (crushing, drying, grinding).
- Burning of the dry mix in a rotary kiln to produce clinker.
- Grinding the clinker to produce the fine cement powder.
- Packaging and storage.
Portland Cement Composition
- C3S (Tricalcium Silicate): High early strength
- C2S (Dicalcium Silicate): Strength increases over time
- C3A (Tricalcium Aluminate): Heat during hydration; gypsum added to reduce heat
- C4AF (Tetracalcium Aluminoferrite): Reduces cement temperature
Mortar
- A mixture of sand or similar inert particles with a binding agent (e.g., cement or lime), and water.
- Mortar Types: Mud mortar, Lime mortar, Cement mortar, Compo mortar
- Mortar Properties: Workability, Strength, Water tightness
- Factors affecting Mortar properties: Mixing water content, binder properties (cement content), sand characteristics (grading, cleanliness).
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Description
Test your knowledge on various types of cement and their properties. This quiz covers topics such as Portland cement, pozzolana cement, and the characteristics of acid-resistant cement. Challenge yourself with questions about the composition and manufacturing processes involved in cement production.
