ASTM C568 Standard Specification for Limestone Dimension Stone

Developed by the American Society for Testing and Materials (ASTM), ASTM C568 Standard Specification for Limestone Dimension Stone describes the material properties, physical requirements, and sampling requirements appropriate for selecting limestone for general building and structural purposes. The ASTM C1242 Standard Guide for Selection, Design, and Installation of Dimension Stone Fastening Systems and ASTM C1528/C1528M Standard Guide for Dimension Stone Selection apply to the proper selection and use of limestone dimension stones.

Dimensional limestone includes stone that has been sawn, split or otherwise worked or shaped and, in particular, excludes units of moulded, cast or otherwise artificially assembled composite pieces, as well as broken and crushed stone.

Dimensional limestone is generally divided into three categories that describe limestones with approximate density ranges:

• I Low-density: Limestone with a density ranging from 1760 to 2160 kg/m3. This category includes soft, porous limestone with lower strength (e.g., chalk or coquina). It is typically used for non-load-bearing interior applications or for decorative purposes.
• II Medium density: Limestone with a density between 2160 and 2560 kg/m3. This category is medium-density limestone suitable for most exterior and interior applications, including cladding and non-structural elements.
• III High-density: Limestone with a density greater than 2560 kg/m3. This category is dense and durable limestone (e.g., some crystalline varieties) used for structural applications, pavements subject to heavy traffic, and exterior facades exposed to harsh conditions.

The physical requirements are determined as follows:

• Limestone supplied under this specification must comply with the physical requirements listed in the table provided in the standard. The physical requirements are listed in the table as follows:
  • Absorption by weight (low density, medium density, high density)
  • Intensity (low intensity, medium intensity, high intensity)
  • Compressive strength (low density, medium density, high density)
  • Modulus of rupture (low density, medium density, high density)
  • Abrasion resistance (low density, medium density, high density)
• Limestone must be sound, durable, and free from spalling, cracks, open seams, pits, or other defects that could compromise its structural integrity in its intended use.
• The desired color and texture for all materials to be produced for the project are determined by control samples, along with any allowable natural variations in material properties. Before production, representative samples should be selected by examining a sufficient number of physical samples that demonstrate all variations in color and texture of the specified limestone.

When necessary, samples to be tested for the purpose of determining characteristic and physical properties should be representative of the limestone to be used in the tests.

Limestone is a sedimentary rock composed primarily of calcium carbonate and typically found in the form of the minerals calcite or aragonite. Formed by the accumulation and compaction of minerals and organic matter over millions of years, limestone is one of the most abundant and widely used rocks on Earth. Its versatility, accessibility, and unique properties make it a cornerstone in construction, industry, and even environmental applications.

In short, the ASTM C568 standard applies to limestone designed for use as dimension stone, including:

• Exterior and interior building facades, cladding and coating.
• Structural elements such as columns and load-bearing walls.
• Decorative applications such as flooring, paving and ornamentation.
• Monuments, statues and other architectural uses.

This standard does not cover crushed or broken limestone used for aggregate, road base or other non-dimensional purposes.

ASTM C568 specifies the physical and mechanical properties of limestone cut stone to ensure it meets performance standards. These properties include:

• Absorption: Maximum water absorption by weight, varying depending on the type:
  • Type I: Up to 12 percent
  • Type II: Up to 7,5 percent
  • Type III: Up to 3 percent

Lower absorption provides better resistance to weathering and moisture damage.

• Density: Minimum density requirements as specified in the classification above.
• Modulus of rupture: Measures flexural strength, minimum values:
  • Type I: 2,76 MPa
  • Type II: 3,45 MPa
  • Type III: 6,89 MPa
• Compressive strength: Ensures that the stone can withstand loads with the following minimum values:
  • Type I: 12,4 MPa
  • Type II: 27,6 MPa
  • Type III: 55,2 MPa
• Abrasion resistance: For stones used in high-traffic areas (e.g., paving), minimum abrasion resistance tested to ASTM C241 or ASTM C1353 standards is required.

The ASTM C568 standard cites several test methods to verify compliance:

• “ASTM C97/C97M Standard test methods for absorption and bulk specific gravity of dimension stone” standard for testing absorption and bulk specific gravity.
• “ASTM C99/C99M Standard test method for modulus of rupture of dimensioned stone” standard for rupture modulus test.
• “ASTM C170/C170M Standard test method for compressive strength of dimensioned stone” standard for compressive strength testing.
• For abrasion resistance testing, see the “ASTM C241/C241M Standard Test Method for Abrasion Resistance of Stone Subjected to Foot Traffic” standard or the “ASTM C1353/C1353M Standard Test Method for Abrasion Resistance of Dimensional Stone Subjected to Foot Traffic, Using a Rotary Platform Abrasive” standard.
• For flexural strength testing (optional for additional evaluation) standard “ASTM C880/C880M Standard Test Method for Flexural Strength of Dimensional Stone”.

Samples should be tested in both dry and wet conditions to simulate real-world performance.

Limestone's wide range of applications stems from its durability, chemical composition, and global availability, making it indispensable in many industries. Limestone that meets the ASTM C568 standard is commonly used in:

• Architectural projects: Facades, interior walls and decorative elements of structures such as museums, courthouses and commercial buildings.
• Road paving and paving: High-density limestone (Type III) for durable, heavily trafficked surfaces.
• Monuments and sculptures: Medium and high density limestone for aesthetic and structural longevity.
• Restoration projects: Adapting historic limestone features for heritage preservation.

The choice of limestone type depends on the application, environmental influences, and structural requirements. For example, Type I limestone is unsuitable for outdoor use in freeze-thaw climates due to its high porosity, while Type III is ideal for these conditions.

The ASTM C568 standard ensures that limestone dimensioned stone is fit for purpose by providing clear criteria for physical properties and performance. It helps architects, engineers, and builders select appropriate materials and ensure safety, durability, and aesthetic quality. The standard also facilitates consistency within the stone industry by providing a common benchmark for suppliers and users worldwide.

Buyers must verify that the stone meets the specified type and performance criteria for their project. Certification may include third-party testing by accredited laboratories to confirm compliance with the standard.

As a result, ASTM C568 is a critical standard for ensuring the quality and suitability of limestone dimension stone for construction and architectural applications. By dividing limestone into three density-based categories and specifying stringent physical requirements, it provides a reliable framework for selecting durable, high-performance stone. This standard helps maintain the integrity and longevity of limestone in a variety of projects, from large facades to intricate sculptures to functional flooring.

Our organization, which has been operating for many years and meticulously follows global developments in science and technology, conducts testing, measurement, and analysis in a wide range of areas for businesses in every sector with a skilled team and extensive infrastructure. In this context, we also provide testing services in accordance with the ASTM C568 Standard Specification for Limestone Dimensioned Stone.