ASTM C1790-21 PDF

Overview

ASTM C1790-21, Standard Specification for Fly Ash Facing Brick, defines the requirements for fly ash bricks used in masonry applications. These bricks are produced from fly ash, water, and appropriate mineral aggregates, with or without additional materials, and specifically exclude the use of portland cement. Instead, strength and durability are achieved through hydraulic, pozzolanic, alkali-activated, or geopolymer chemical reactions. The standard specifies physical properties, dimensional tolerances, finish and appearance criteria, and testing methods for fly ash facing brick. This specification is published by ASTM International and is intended for both structural and facing applications in construction.

Key Topics

• Material Composition:
  • Bricks are made using fly ash, water, and mineral aggregates, without portland cement.
  • Allowable binders include pozzolans, slag cement, and silica fume.
  • Pigments may be added for integrally colored units.
• Physical Requirements:
  • Minimum compressive strength and density classifications (lightweight, medium, normal weight).
  • Requirements for maximum water absorption and dimensional tolerances.
  • Limits on total linear drying shrinkage to ensure shape retention.
• Durability and Testing:
  • Freeze-thaw resistance and mass loss are tested to demonstrate durability.
  • Units are evaluated for defects and appearance, with criteria for chipped or cracked units.
• Compliance and Quality Control:
  • Guidelines for sampling and testing procedures.
  • Acceptance or rejection based on conformance to physical, dimensional, and appearance criteria.
• Environmental Scope:
  • Exclusion of portland cement supports initiatives using recycled materials and lower embodied carbon in masonry.

Applications

Fly ash facing bricks specified by ASTM C1790-21 are widely used in:

• Commercial and Residential Masonry: For construction of durable, environmentally sustainable facades and structural walls.
• Public Infrastructure: Including retaining walls, civic buildings, and architectural features that require consistent appearance and performance.
• Structural and Non-Structural Components: These bricks are suitable for both load-bearing and decorative elements in building design.
• Sustainable Construction Projects: Fly ash bricks contribute to improved sustainability by incorporating industrial byproducts, supporting recycling efforts, and minimizing reliance on traditional cementitious materials.

This standard provides a reliable basis for manufacturers, designers, specifiers, and builders to ensure consistent quality, performance, and aesthetics in masonry construction projects using fly ash facing bricks.

Related Standards

The following ASTM standards are referenced within ASTM C1790-21 and provide additional details on materials, testing, and definitions:

• ASTM C33 - Specification for Concrete Aggregates
• ASTM C140 - Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
• ASTM C331 - Specification for Lightweight Aggregates for Concrete Masonry Units
• ASTM C426 - Test Method for Linear Drying Shrinkage of Concrete Masonry Units
• ASTM C618 - Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
• ASTM C979 - Specification for Pigments for Integrally Colored Concrete
• ASTM C989 - Specification for Slag Cement for Use in Concrete and Mortars
• ASTM C1232 - Terminology for Masonry
• ASTM C1240 - Specification for Silica Fume Used in Cementitious Mixtures
• ASTM C1645 - Test Method for Freeze-thaw and De-icing Salt Durability of Solid Concrete Interlocking Paving Units

Utilizing ASTM C1790-21 ensures the production and use of high-quality fly ash facing bricks, supporting innovation, sustainability, and performance in modern masonry construction.