Coarse Aggregate for Portland Cement Concrete

AASHTO M 80-87: Standard Specification for Coarse Aggregate for Portland Cement Concrete

For engineers and construction professionals engaged in concrete design and production, understanding the foundational specifications for materials is paramount. AASHTO M 80-87, the "Standard Specification for Coarse Aggregate for Portland Cement Concrete," stands as an essential document, providing a comprehensive framework for selecting and evaluating the critical coarse aggregate component of concrete mixes. Adherence to this industry-leading standard ensures the integrity, durability, and performance of countless infrastructure and building projects.

What is AASHTO M 80-87?

AASHTO M 80-87 is an authoritative standard developed by the American Association of State Highway and Transportation Officials. It specifically addresses the requirements for coarse aggregate, excluding lightweight varieties, intended for use in Portland cement concrete. The standard establishes criteria for general characteristics, grading, deleterious substances, and physical properties, ensuring that the chosen aggregate contributes positively to the final concrete's performance and longevity.

Scope & Purpose

This standard governs the selection, testing, and acceptance of coarse aggregates, which include materials like gravel, crushed stone, and air-cooled blast-furnace slag. It defines various classes and gradings of coarse aggregate suitable for different concrete applications, from pavements to structural elements. While it provides a comprehensive baseline, it also acknowledges that project-specific needs or regional conditions may necessitate more stringent or less restrictive requirements, as noted in its supplementary guidance. The standard does not cover lightweight aggregates.

Who Must Comply?

• • Primary audience: Civil Engineers, Materials Engineers, Quality Control Inspectors, Construction Managers, and Concrete Technologists.
• • Industries affected: Construction, Civil Engineering, Infrastructure Development, Building Materials Manufacturing.
• • Compliance nature: Mandatory for projects specifying adherence to AASHTO standards, and recommended for general best practice in quality concrete production.
• • Enforcement: Compliance is typically overseen by project engineers, transportation department representatives, and independent testing laboratories.

Key Requirements Overview

The standard requires that coarse aggregate be free from detrimental materials that could negatively impact concrete's strength, durability, or appearance. Professionals must ensure that aggregates conform to specified gradings, often referencing AASHTO M 43 for size designations, to achieve proper workability and consolidation in concrete mixes. Key provisions include adhering to limits for deleterious substances such as clay lumps, friable particles, and materials finer than the 75-µm (No. 200) sieve, as detailed in Table 2. Furthermore, the standard mandates evaluation for soundness and resistance to degradation, with specific tests like the Los Angeles Abrasion test and sulfate soundness tests, to predict long-term performance. The potential for alkali-aggregate reactivity must also be assessed for concrete exposed to moisture or humid conditions.

Related Standards & References

AASHTO M 80-87 is intrinsically linked with other AASHTO standards for comprehensive aggregate management. AASHTO M 43, "Sizes of Aggregate for Road and Bridge Construction," is essential for specifying the desired aggregate gradings. AASHTO T 2, "Sampling of Aggregates," and AASHTO T 27, "Sieve Analysis of Fine and Coarse Aggregates," are critical for conducting the necessary sampling and testing procedures to verify compliance with M 8