Materials of Construction: Cement Binders

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary difference between non-hydraulic cements and hydraulic cements?

Hydraulic cements do not need calcium compounds to harden, while non-hydraulic cements require calcium hydroxide for hardening.

Non-hydraulic cements harden in water, while hydraulic cements do not.

Non-hydraulic cements set and harden in air only, while hydraulic cements can set and harden both in air and under water. (correct)

Non-hydraulic cements are not stable upon exposure to moisture, while hydraulic cements remain stable when exposed to water.

What is the purpose of adding gypsum to Portland cement?

To prevent the setting of the cement (correct)

To accelerate the setting of the cement

To reduce the setting time of the cement

To increase the strength of the cement

What is the maximum allowable SO3 content in ordinary Portland cement according to ASTM C150?

3% (correct)

What type of compound is calcium hydroxide?

Inorganic compound Signup and view all the answers

Why does the presence of a high content of MgO and free lime in cement lead to expansion upon slaking?

Because their reactions are rather slow Signup and view all the answers

Why is portland cement grayish in color?

Due to the presence of iron oxide Signup and view all the answers

What problem can arise when cement with high alkalies content is used with reactive aggregates in concrete production?

Formation of alkali-silica gel causing disintegration Signup and view all the answers

How is portland cement different from hydraulic lime?

Portland cement can set and harden both in air and under water, while hydraulic lime can only set in air. Signup and view all the answers

Which material is NOT considered a cementitious material?

Bituminous Materials Signup and view all the answers

Why does expansion in hardened concrete lead to cracking?

Thermal stress Signup and view all the answers

What is the total alkali content limit (%Na2O+0.658%K2O=equivalent Na2O) when using cement with reactive aggregates?

0.6% Signup and view all the answers

What is the primary role of gypsum in Portland cement production?

To control the setting time of the cement Signup and view all the answers

What is the main chemical reaction responsible for the hardening of Portland Cement paste?

Reaction between water and compounds in Portland Cement Signup and view all the answers

In the manufacturing process of Portland Cement clinker, what are the two main raw materials used?

Limestone and Clay Signup and view all the answers

What is added to raw materials before they are turned into cement to facilitate the process?

Gypsum Signup and view all the answers

Which material is combined with cement paste to produce mortar?

Sand Signup and view all the answers

For asphalt construction, what should be done if using clinker as a material?

Apply appropriate specifications Signup and view all the answers

'Kaolin' is composed of which chemical elements?

Aluminium oxide and Water Signup and view all the answers

What is the purpose of adding gypsum to clinker in the manufacturing of cement?

To prevent flash setting of the cement Signup and view all the answers

Which stage involves grinding the burned product, known as 'clinker,' together with some gypsum?

Cement grinding and storage Signup and view all the answers

In which manufacturing process are the raw materials ground wet and fed to the kiln as a slurry?

Wet process Signup and view all the answers

At what temperature does the clinker leave the kiln before entering a cooling zone?

$1000°C$ Signup and view all the answers

Which step of the cement manufacturing process involves raw meal drying, grinding, and homogenization?

Raw meal drying, grinding, and homogenization Signup and view all the answers

What is the key difference between the dry and semidry processes in cement manufacturing?

Method of feeding raw materials to the kiln Signup and view all the answers

Which compound is formed during the hydration of Portland cement and releases the most heat?

Calcium-alumino-monosulfohydrate Signup and view all the answers

Which of the following is NOT classified as one of the five main types of cements covered by TS EN 197-1?

Organic material content cement Signup and view all the answers

What are the two most important hydraulic constituents in Portland cement?

$C2S$ and $C3A$ Signup and view all the answers

Which compound is NOT considered one of the major compounds in Portland cement clinker?

$C6A S 3H32$ Signup and view all the answers

What does CEM IV stand for in the classification of cements under TS EN 197-1?

Pozzolanic cement Signup and view all the answers

What is the main difference between CEM II/A-L and CEM II/B-L cements?

Presence of natural pozzolan in the mix Signup and view all the answers

Study Notes

Cement Materials of Construction

Binders: materials with adhesive properties, including glues (animal or vegetable sources, synthetic polymers), bituminous materials (complex hydrocarbons), and calcium compounds (gypsum, lime, portland cement).

Calcium-Based Binders (Cements)

Will harden and develop binding properties when mixed with water.
Include gypsum, lime, and portland cement.

Cementitious Materials

Gain binding properties upon hydration or reaction with Ca(OH)2 (calcium hydroxide).
Include non-hydraulic cements (lime, gypsum) and hydraulic cements (hydraulic lime, portland cement).

Portland Cement

A hydraulic binder produced by intergrinding a small amount of gypsum and portland cement clinker.
Name derived from its resemblance to Portland stone.
Normally grayish in color due to iron oxide presence.
When mixed with water, forms a plastic paste that can be molded into any shape, gaining rigidity and hardening over time.

Properties of Portland Cement

Contains 30% clay and 70% limestone in cooked form.
Mixed with gypsum at a rate of 2-6% by weight and thoroughly grinded.
Used in making mortars and concretes.

Manufacture of Portland Cement

Main raw materials: limestone (CaCO3) and clay.
Clays have various amounts of SiO2 (silicon dioxide) and AI2O3 (aluminium oxide); kaolin, pure clay is composed of AI2O3.2SiO2.2H2O.
Four stages in the manufacture of portland cement: crushing and grinding raw materials, blending, burning the prepared mix in a kiln, and grinding the burned product (clinker) together with gypsum.

Hydration of Portland Cement

Hydration reactions between cement compounds and water, resulting in the formation of complex compounds.
Calcium silicates (C2S and C3S) are the most important hydraulic constituents.

Types of Cements Produced in Turkey

TS EN 197-1 covers 27 standard cements classified into five main types: CEM I (Portland cement), CEM II (Portland composite cement), CEM III (Blast furnace slag cement), CEM IV (Pozzolanic cement), and CEM V (Composite cement).

Chemical Composition of Portland Cement

Oxide composition: includes C3S, C2S, C3A, and C4AF.
Gypsum retards quick setting, but excessive gypsum can lead to disruptive expansion.
ASTM C150 and TS EN 197-1 regulate SO3 content in ordinary portland cement.
High MgO and free lime content can cause expansion upon slaking.
Alkalies can react with reactive silica in aggregates, forming alkali-silica gel and causing expansion and cracking.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on different materials with adhesive properties used in construction, including glues, bituminous materials, and calcium-based binders like gypsum, lime, and Portland cement.