17. Lecture 17-Masonry6

Course Details

  • Course Name: CIVE 2700: Civil Engineering Materials

  • Instructor: Hamzeh Hajiloo, PhD, PEng

  • Lecture Title: Lecture 17: Masonry

  • Chapter: 8 - Masonry Materials for Civil and Construction Engineers

  • Authors: Michael Mamlook, John Zaniewski

Masonry Constructions

Types of Masonry Units

  1. Clay Bricks

  2. Concrete Masonry Units (CMUs)

  3. Stone

  4. Mortar

Weaknesses of Masonry Buildings

  • Vulnerability to environmental conditions

  • Structural instability under certain loads

Overview of Masonry Structures

  • A masonry structure combines masonry units with mortar.

  • Utilizes bricks, concrete blocks, or stone for building walls and architectural elements.

  • Masonry Units Include:

  • Concrete masonry units (CMUs)

  • Clay bricks (solid or hollow)

  • Structural clay tiles

  • Stone

  • Mortar Types:

  • Cement Mortar

Advantages and Disadvantages of Masonry

Advantages

  • Durability: Long-lasting and resilient against environmental elements (fire, moisture, extreme temperatures).

  • Requires less formwork than traditional concrete.

  • Material Availability: Easy to source materials.

  • Simplicity: Straightforward construction technique.

  • Non-combustibility: Higher fire resistance compared to other materials.

Disadvantages

  • Labor Intensity: Requires skilled labor.

  • Construction Speed: Slower than other methods.

  • Weight: Heavy materials can complicate transportation and handling.

  • Strength Limitations: Only compressive capacity with weakness in tension.

  • Low Tolerance: Less resistant to oscillation.

Quality Factors in Masonry Construction

  1. Quality of Materials

  2. Quality of Mortar

  3. Workmanship

  4. Assembly Pattern

Applications of Masonry in Construction

Primary Structural Functions

  • Load-Bearing Walls: Support vertical loads (roof, floors).

  • Exterior Cladding: Provides aesthetics and environmental protection.

  • Partition Walls: Defines interior spaces without bearing loads.

  • Architectural Features: Creates elements such as arches and decorative facades.

Masonry Types by Load Conditions

Load-Bearing Walls

  • Carry loads from other members.

Non-Load-Bearing Walls

  • Only carry their own weight (e.g., partition walls).

Additional Topics on Masonry Units

Clay Bricks

  1. Types of Clay Bricks:

  • Modular (perforated)

  • Non-Modular (solid)

  1. Uses:

  • Common bricks (strong, durable for structural uses)

  • Facing bricks (aesthetically appealing finishes for exterior walls)

  • Floor and paving bricks (durable surfaces for floors and pavements)

  1. Specifications:

  • Described by nominal dimensions (width, height, length).

Clay Brick Manufacturing Process

  1. Vitrification: Ensures impermeability to water.

  2. Kiln Firing: Gradually heat bricks over 1,000°C to harden.

  3. Cooling: Slow cooling prevents thermal shock and cracks.

Concrete Masonry Units (CMUs)

Features and Versatility

  • Available in various sizes, shapes, and textures.

  • Density Types:

    • Normal weight: made from sand, gravel, crushed stone.

    • Lightweight: made from expanded clay, shale for insulation and fire resistance.

Manufacturing of CMUs

  • Process involves pressure molding with a dry concrete mix (zero slump).

  • Curing necessary for strength development.

Compressive Strength of CMUs

  • Measured using ASTM standards.

  • Strength calculations based on load and cross-sectional area.

Stone Types Used in Masonry

Classification of Stones

  1. Igneous Stones:

  • High strength, e.g., granite and basalt.

  1. Sedimentary Stones:

  • Easier to work with, e.g., sandstone and limestone.

  1. Metamorphic Stones:

  • High strength, e.g., marble and quartzite.

Compressive Strength and Density of Stone

  • Compressive strengths of various stones (e.g., clay brick, limestone, marble).

Mortar Composition and Functions

Components

  • Main Components: Cementitious material, fine aggregates (sand), and water (no coarse aggregate).

  • Types include cement mortar and cement-lime mortar.

Functions of Mortar

  1. Bonds masonry units.

  2. Seals structures against air and water.

  3. Provides structural integrity and aesthetics.

Properties of Mortar

Testing and Strength

  • Tensile Bond Strength: Important for adhesion and sealant properties.

  • Workability and strength properties essential for effective application.

Additional Components in Masonry

Grout

  • High-slump concrete for filling voids in hollow masonry units.

  • Increases load-bearing capacity and fire resistance.

Structural Reinforcement

  • Reinforcement Techniques: Using steel bars and filling voids to enhance strength.

  • Bond Beams: Reinforced elements at the top of walls for stability.

Seismic Considerations

Vulnerabilities

  • Masonry structures can be weak during earthquakes due to out-of-plane failures.

Strengthening Measures

  • Suggested techniques include incorporating reinforcement such as rebar or grouted cells.