Fiber-Reinforced Concrete—From Fresh Properties to Structural Design: New Tools, Guides, and Reports-An Overview of Two Documents—ACI 544.9R and ACI 544.2R-17 Report on the Measurement of Fresh State Properties (PDF)

An Overview of Two Documents—ACI 544.9R and ACI 544.2R-17 Report on the Measurement of Fresh State Properties (PDF)

Pdf Summary

The document discusses key findings and methodologies in evaluating both fresh and hardened properties of Fiber-Reinforced Concrete (FRC), specifically focusing on fiber dispersion and mechanical performance. The ACI 544.2R-17 report addresses measuring fresh state properties and fiber dispersion in FRC. It covers aspects such as workability, fiber orientation, and whether standard tests for plain self-consolidating concrete (SCC) are applicable to fiber-reinforced (FR) SCC. Techniques include calculating resistance to static and dynamic segregation of fibers with standardized tests like slump flow and using methods for observing fiber dispersion.<br /><br />Fiber dispersion monitoring is conducted through techniques such as washing and sieving fibers, employing both destructive methods—like drilling cores to assess fiber concentration—and non-destructive approaches like X-ray or electromagnetic methods. The reports also highlight advanced techniques, including Alternative-Current Impedance Spectroscopy and magnetic inductance, as tools for evaluating fiber dispersion and orientation accurately.<br /><br />ACI 544.9R-17 focuses on hardened state properties, discussing various tests designed to measure the mechanical performance of hardened FRC. These include compression, direct tension, indirect tension (like the Double Edge Wedge Splitting test), and flexural tests adhering to ASTM and EN standards. The document notes the utilization of both traditional and high strain rate tests, such as impact and shock tests, to determine the FRC's durability and toughness.<br /><br />Overall, the reports underscore the importance of tailored testing to account for the unique characteristics imparted by the addition of fibers in concrete. Methods and standards continuously evolve to meet the demands of reliably assessing both the fresh and hardened states of FRC, crucial for its optimal use in construction.

Keywords

Fiber-Reinforced Concrete

fiber dispersion

mechanical performance

ACI 544.2R-17

fresh state properties

hardened state properties

workability

non-destructive testing

Alternative-Current Impedance Spectroscopy

ASTM standards