Building Materials Chapter 1

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Questions and Answers

What holds the negatively charged electrons in position in an atom?

A gravitational pull

An electrostatic attraction (correct)

A magnetic field

A strong nuclear force

What is the main characteristic of ionic bonds?

High melting point and volatility

Weak bonding force

Sharing of electrons between atoms

Transfer of an electron between atoms (correct)

What is the main characteristic of covalent bonds?

Transfer of electrons between atoms

Weak bonding force

High melting point and volatility

Sharing of electrons between atoms (correct)

What is the main characteristic of metallic bonds?

Delocalization of valence electrons Signup and view all the answers

What is a limitation of ionic bonds?

They can only occur between atoms of different elements Signup and view all the answers

Which type of bond has high strength, hardness, and melting point?

Covalent bond Signup and view all the answers

What is a characteristic of metals due to their bonding?

Good thermal conductivity Signup and view all the answers

Which type of bond has soluble compounds?

Ionic bond Signup and view all the answers

What is the result of atoms arranging themselves in the most stable patterns possible?

They complete or fill their outermost electron orbits Signup and view all the answers

What is the driving force behind atoms joining with other atoms?

To complete or fill their outermost electron orbits Signup and view all the answers

What is the primary factor that determines the properties of materials?

Chemical composition Signup and view all the answers

What is the result of increasing the carbon content in carbon steel?

Increased strength, hardness, and toughness Signup and view all the answers

What is the purpose of adding chromium and nickel to carbon steel?

To improve corrosion resistance Signup and view all the answers

What is the level of structure that can be identified with a magnifying glass or naked eyes?

Macro-structure Signup and view all the answers

Which type of materials typically consist of a variety of mineral compositions?

Inorganic materials Signup and view all the answers

What is the term for the chemical constituents of a material?

Chemical composition Signup and view all the answers

Which of the following materials exhibits different characteristics due to different clinkers?

Cement Signup and view all the answers

What is the term for the monomers and compounds with a certain chemical composition and structure?

Minerals Signup and view all the answers

Which of the following is NOT a level of structure in materials?

Bio-structure Signup and view all the answers

What is the primary factor that determines the properties of natural stone?

Mineral composition Signup and view all the answers

What is the minimum scale that must be considered in engineering level?

The size of the representative cell Signup and view all the answers

What is the shape of the representative cell if the material is isotropic?

Cube Signup and view all the answers

What is the main focus of study in meso-structure?

The size, shape and interface of grains and particles Signup and view all the answers

What is the range of linear dimensions of the representative cell for metals?

10^-3 m to 10^-2 m Signup and view all the answers

What is the range of linear dimensions of the representative cell for concrete?

10^-1 m to 1 m Signup and view all the answers

What is the tool used to study microstructure?

All of the above Signup and view all the answers

What is the size of the wall thickness of a wood cell?

5 × 10^-6 m Signup and view all the answers

What is the length of a brick?

0.225 m Signup and view all the answers

What is the characteristic of an anisotropic material?

Properties can only be described with reference to orientation Signup and view all the answers

What is the characteristic of a material at the meso-structure level?

The material is considered as a composite of different phases Signup and view all the answers

Study Notes

Materials Composition and Structure

Materials composition includes chemical composition and mineral composition, which are key factors for the properties of materials.
Chemical composition refers to the chemical constituents, and varying chemical compositions result in different properties.
For example, increasing carbon content in carbon steel changes its strength, hardness, and toughness, making it prone to rust, which can be addressed by adding chromium, nickel, and other chemical components to create stainless steel.

Mineral Composition

Many inorganic materials consist of various mineral compositions, which are key factors for the properties of some building materials (e.g., natural stone, inorganic gel, and other materials).
Cement exhibits different characteristics due to different clinkers.

Structure of Materials

The structures of materials can be divided into macro-structure, meso-structure, and micro-structure, which are key factors related to the properties of materials.

Macro-structure

Macro-structure refers to the thick structure above millimeter that can be identified with a magnifying glass or naked eyes.
At the engineering level, the total material is considered, and it is normally taken as continuous and homogeneous, with average properties assumed throughout the whole volume of the material body.
The minimum scale that must be considered is governed by the size of the representative cell, which varies from 10^(-3) m for metals to 0.1 m for concrete and 1 m for masonry.

Meso-structure

Meso-structure refers to the micro-level structure that can be observed by optical microscope.
It includes the size, shape, and interface of grains and particles, and the size, shape, and distribution of pores and micro-cracks.
The material is considered as a composite of different phases, which interact to realize the behavior of the total material.

Microstructure

Microstructure refers to the atomic and molecular structures of materials that can be studied by electron microscopy, X-ray diffractometer, and other means.
Atoms consist of a nucleus surrounded by a cloud of orbiting electrons, and the nucleus consists of positively charged protons and neutral neutrons.

Bonding of Atoms

Atoms tend to arrange themselves in the most stable patterns possible, which means they have a tendency to complete or fill their outermost electron orbits.
Ionic bonding involves a transfer of an electron, resulting in high strength, hardness, and melting point, but also volatility and medium density.
Covalent bonding involves the sharing of electrons between two atoms, resulting in strong bonding force, high strength, hardness, melting point, and density.
Metallic bonding involves sharing electrons, resulting in volatile strength and hardness, high density, and good thermal and electrical conductivity.

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Description

This quiz covers the basics of building materials, specifically chapter one. It is designed for civil engineering students at the University of Halabja.