ASTM C1697-21 PDF

Overview

ASTM C1697-21: Standard Specification for Blended Supplementary Cementitious Materials establishes requirements for blended supplementary cementitious materials (SCMs) produced by blending or intergrinding two or three SCMs. These materials are used in concrete and mortar mixes to achieve hydraulic or pozzolanic action, or both, improving performance and durability. Covered SCMs include slag cement (per ASTM C989/C989M), natural pozzolans and fly ash (per ASTM C618), and silica fume (per ASTM C1240). The standard applies globally as per World Trade Organization (WTO) principles and specifies that only SI units are to be used.

Key Topics

• Blend Composition and Classification
  • Blends may include combinations of Class N pozzolan, Class F and C fly ash, slag cement, and silica fume.
  • Classification of blended SCMs is determined by the predominant constituent, using a standardized naming convention (e.g., SCMb 2 65C/35S for 65% Class C fly ash and 35% slag cement).
• Physical and Chemical Requirements
  • The standard outlines testing and reporting methods for chemical composition, ensuring key constituents meet their respective ASTM standards.
  • Blended SCMs must be uniform and accurate in blend proportions, with specific permissible variations outlined for manufacturing control.
• Optional and Additional Requirements
  • Purchasers may specify optional criteria, including drying shrinkage, alkali-silica reaction (ASR) control, sulfate resistance, and uniformity.
  • Methods for verification of blend proportions and quality control are detailed, including mechanical and chemical analysis.
• Ordering, Packaging, and Certification
  • Orders must specify blend composition. Packaging and shipment must clearly indicate blend details and manufacturer information.
  • Certification and test reports for both individual constituents and the blend may be requested by purchasers.

Applications

Blended supplementary cementitious materials are increasingly vital in modern construction practices due to their contribution to sustainable and high-performance concrete. Key practical applications include:

• Concrete and Mortar Production Use in a variety of concrete and mortar mixes where hydraulic and pozzolanic reactions are desired for enhanced durability and performance.
• Mitigation of Alkali-Silica Reaction (ASR) When properly proportioned, blended SCMs can reduce the risk of ASR, a common cause of concrete degradation. ASTM C1778 provides guidance on this application.
• Improvement of Sulfate Resistance Blended SCMs can enhance the sulfate resistance of concrete, a critical property for structures exposed to sulfate-rich environments.
• Lower Environmental Impact By substituting a portion of portland cement with SCMs, blends reduce clinker content, lowering CO₂ emissions in concrete production.
• Quality and Uniformity in Blended Materials Blended SCMs provide a consistent, factory-controlled product ensuring reliable performance across uses.

Related Standards

The following standards are frequently referenced with ASTM C1697-21, supporting the use and specification of blended supplementary cementitious materials:

• ASTM C618 - Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
• ASTM C989/C989M - Specification for Slag Cement for Use in Concrete and Mortars
• ASTM C1240 - Specification for Silica Fume Used in Cementitious Mixtures
• ASTM C311/C311M - Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans
• ASTM C114 - Test Methods for Chemical Analysis of Hydraulic Cement
• ASTM C183/C183M - Practice for Sampling Hydraulic Cement
• ASTM C125 - Terminology Relating to Concrete and Concrete Aggregates
• ASTM C150/C150M - Specification for Portland Cement
• ASTM C1778 - Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete

For additional application guidelines, users are referred to the ACI Manual of Concrete Practice, including:

• ACI 232 series (natural pozzolans and fly ash)
• ACI 233 (slag cement)
• ACI 234 (silica fume)

Keywords: blended supplementary cementitious materials, ASTM C1697-21, concrete, fly ash, slag cement, pozzolan, silica fume, ASR mitigation, sulfate resistance, construction materials standard.