Stone Masonry

Stone Masonry

Learning Objectives

• Understand the various types of commercial building stones

• Identify important factors to consider in selecting masonry stone

• Comprehend the manufacturing steps of stone masonry

• Recognize different construction and configuration types of stone masonry

Commercial Stone

Definition of Commercial Building Stone

• Rock taken from the earth and shaped for construction purposes.

• Stone is recognized as a natural and diverse building material.

Installation Methods

• Stone is laid in mortar, similar to brick construction.

• It can also be mechanically attached to the building frame as a facing, referred to as stone cladding.

Classification of Commercial Building Stone

According to ASTM C119, commercial building stone is classified into six groups:

1. Granite

2. Limestone

3. Quartz-based

4. Slate

5. Marble

6. Other

Types of Stone

Granite Group

• Characteristics:
    - Nonporous, considered the strongest stone, very durable.
    - Suitable for exposure to severe weathering and ground contact.
    - Available in a variety of colors.
    - Can accept multiple finishes, including polished.

• Common Usage:
    - Most commonly quarried stone for construction in North America.

Limestone Group

• Characteristics:
    - Strength and porosity depend on density.
    - Range of colors including white, gray, and red.
    - Typically features a textured finish.

Quartz-Based Group

• Characteristics:
    - Varies in density and porosity.
    - Color varies significantly based on the binding materials of the quartz particles.
    - Not capable of being polished, e.g. Sandstone.

Slate Group

• Characteristics:
    - Derived from shales (mineral clays).
    - Dense, hard stone featuring closely spaced layers or "planes."
    - Available in a variety of colors.

Marble Group

• Characteristics:
    - Exhibits a wide range of physical properties and appearance.
    - Many color variations, often with extensive veining.
    - Easily polished.

"Other" Group

• Travertine:
    - Partially crystallized and patterned calcite.
    - Chemically similar to limestone, with physical properties akin to marble.

• Other stone types include:
    - Alabaster
    - Greenstone
    - Schist
    - Serpentine
    - Soapstone

Selecting Stone for Buildings

Key Considerations

1. Aesthetic: Visual appearance and design compatibility.

2. Durability: Should withstand varying environmental factors.

3. Strength: Load-bearing capabilities.

4. Economical: Local sourcing for cost efficiency.

5. Performance History: Evaluating past history as a predictor of future performance in similar conditions.

6. Petrographic Analysis: Microscopic analysis to examine mineral content and structure.

Properties Laboratory Testing

Critical tests to determine:

• Water absorption.

• Density.

• Compressive strength.

• Dimensional stability.

• Freeze-thaw resistance.

• Chemical resistance.

• Flexural strength.

Stone Selection Properties

• A correlation exists between high density, low water absorption, and greater durability.
    - Water Absorption by Weight, Maximum Density, Minimum Density:
      - Granite:
        - Water Absorption: 0.40 ext{}
        - Density: $1760-2560 ext{ kg/m}^3$
      - Limestone:
        - Water Absorption: 3-12 ext{}
        - Density: $110-160 ext{ lb/ft}^3$
      - Sandstone:
        - Water Absorption: 1-8 ext{}
        - Density: $125-160 ext{ lb/ft}^3$
      - Marble:
        - Water Absorption: 0.20 ext{}
        - Density: $2305-2595 ext{ kg/m}^3$

• Compressive Strength, Minimum:
      - Granite: $19,000 ext{ psi} ext{ (131 MPa)}$
      - Limestone: $1800-8000 ext{ psi} ext{ (12-55 MPa)}$
      - Sandstone: $4000-20,000 ext{ psi} ext{ (27.6-137.9 MPa)}$
      - Marble: $7500 ext{ psi} ext{ (52 MPa)}$

• Modulus of Rupture, Minimum:
      - Granite: $1500 ext{ psi} ext{ (10.34 MPa)}$
      - Limestone: $400-1000 ext{ psi} ext{ (2.9-6.9 MPa)}$

• Flexural Strength, Minimum:
      - Granite: $1200 ext{ psi} ext{ (8.27 MPa)}$
      - Limestone: $1000 ext{ psi} ext{ (7 MPa)}$

Quarrying

Different Forms of Stone Used in Construction

1. Fieldstone: Rough building stone sourced from river beds or rocky fields.

2. Rubble: Irregular fragments quarried with at least one good face.

3. Dimension Stone: Quarried and precisely cut into rectangular shapes (includes “cut stone” and small blocks known as “ashlar”).

4. **Methods of Quarrying: **
      - Advanced machinery, especially diamond blades for limestone and marble.
      - Granite requires specialized methods, typically blasting or jet burners.

5. Flagstone: Thinner slabs, either rectangular or irregular, primarily used for flooring or paving.

Milling Processes

Sawing

• Band Sawing: Typically utilized for curved cuts and intricate designs in stone.

• Circular Sawing: Commonly used for straight cuts on flat surfaces.

Hand Carving

• Traditional method involving manual tools to shape stone features.

Stone Masonry Configurations

• General Information: Stone masonry may be dry set, stacked without mortar, or set on shims with sealant-filled joints.

Rubble Masonry

• Random Rubble: Laid without continuous horizontal joints, presenting an irregular pattern.

• Coursed Rubble: Laid with continuous horizontal joints, providing a more structured appearance.

Ashlar Masonry

• Random Ashlar: Features random patterns with specific stones being carefully shaped.

• Coursed Ashlar: Stone blocks are laid in horizontal layers, promoting consistent alignment and aesthetic appeal.