ASTM C1399 – Standard Test Method for Obtaining Average Residual-Strength of Fiber-Reinforced Concrete

ASTM C1399 – Average Residual-Strength of Fiber-Reinforced Concrete

ASTM C1399 covers the determination of residual strength of a fiber–reinforced concrete test beam.

The average residual strength is computed using specified beam deflections that are obtained from a beam that has been cracked in a standard manner.

The test provides data needed to obtain that portion of the load–deflection curve beyond which a significant amount of cracking damage has occurred and

it provides a measure of post–cracking strength, as such strength is affected by the use of fiber–reinforcement.

A third point bend test or four point bend test can be performed.

In four point bend tests, the maximum flexural stress is spread out over the section of the beam between loading points.

Third point bending is a special form of four point bending tests only with three equal spans.

The stress concentration of a four point test is over a large region, avoiding premature failure.

Significance and Use

This test method provides a quantitative measure useful in the evaluation of the performance of fiber–reinforced concrete.

It allows for comparative analysis among beams containing different fiber types, including materials, dimension and shape, and different fiber contents.

Results can be used to optimize the proportions of fiber–reinforced concrete mixtures, to determine compliance with construction specifications, to evaluate

fiber–reinforced concrete which has been in service, and as a tool for research and development of fiber–reinforced concrete

*** Before conducting ASTM C1399 , it is important to read the entire specification. Standards can be obtained from appropriate standard authorities