Masonry units, segmental pavers and flags-Methods of test - Method 12: Determining coefficients of contraction

AS/NZS 4456.12:2003: Masonry units, segmental pavers and flags-Methods of test - Method 12: Determining coefficients of contraction

Ensuring the long-term performance and stability of masonry structures relies heavily on understanding the inherent properties of building materials. For engineers and designers working with masonry units, segmental pavers, and flags, accurately quantifying their potential for shrinkage is paramount. AS/NZS 4456.12:2003 provides the essential, industry-leading methodology for this critical material characterization.

What is AS/NZS 4456.12:2003?

This authoritative standard, developed by AS/NZS, outlines proven methods for determining the coefficients of contraction in masonry units, segmental pavers, and flags. Its primary purpose is to provide a standardized approach to measure both residual curing contraction and drying contraction, offering crucial data for material selection and design.

Scope & Purpose

AS/NZS 4456.12:2003 governs the precise testing procedures required to quantify the dimensional changes that occur in masonry units as they undergo secondary curing and subsequent drying. It specifies how to prepare specimens, the apparatus required, and the step-by-step process for measurement and calculation. The standard focuses specifically on contraction coefficients and does not cover other material properties or performance criteria for masonry units.

Who Must Comply?

• • Primary audience: Materials Engineers, Civil Engineers, Quality Control Technicians, Laboratory Technicians, and Building Inspectors.
• • Industries affected: Construction, Building Materials Manufacturing, and Civil Engineering.
• • Compliance nature: Voluntary, but highly recommended for quality assurance and design integrity.
• • Enforcement: Compliance is typically driven by project specifications, contractual agreements, and internal quality management systems.

Key Requirements Overview

The standard requires professionals to:

• • Implement standardized procedures for measuring residual curing contraction, which indicates shrinkage during the secondary curing phase.
• • Conduct controlled tests to determine drying contraction, reflecting shrinkage as saturated units dry under ambient conditions.
• • Utilize specific apparatus, including precision measuring frames and temperature-controlled environments, to ensure accurate and repeatable results.
• • Calculate contraction coefficients using defined formulae, ensuring units are expressed in millimetres per metre.
• • Maintain detailed records of all test parameters, measurements, and calculated coefficients for traceability and reporting.

Related Standards & References

AS/NZS 4456.12:2003 is an integral part of the broader AS/NZS 4456 series. It directly references:

• • AS/NZS 4456.0: Provides the general introduction and a comprehensive list of all testing methods within the series, offering context for this specific method.
• • AS/NZS 4456.1: Outlines the essential procedures for sampling, ensuring that test specimens are representative of the material being evaluated.
• • AS/NZS 4456.2: Details the methods for assessing mean and standard deviation, crucial for interpreting test results and understanding variability within a material batch.

By adhering to AS/NZS 4456.12:2003, engineers and manufacturers can confidently assess and specify