Flexural Toughness of Fiber Reinforced Concrete ASTM C1550

Scope:

Flexural toughness of fiber-reinforced concrete is determined by ASTM C1550. It is expressed as energy absorption in the post-crack range using a round panel supported on the three symmetrically arranged pivots and subjected to a central point load. The performance of specimens tested by Flexural toughness method. It  is quantified in terms of the energy absorbed between the onset of loading and selected values of central deflection.

The main advantage of ASTM C 1550 is that , it gives similar results to other toughness tests, and with lower variability. This test method is commonly used for evaluating the toughness of fiber reinforced concrete and is mainly used in the tunnel linings and mining industry. 

Test Procedure:

The post-crack behavior of plate-like, fiber-reinforced concrete structural members is well represented by a centrally loaded round panel test specimen that is simply supported on the three pivots symmetrically arranged around its circumference. Such a test panel experiences bi-axial bending in response to a central point load and exhibits a mode of failure related to the in situ behavior of structures. The post-crack performance of round panels subject to a central point load can be represented by the energy absorbed panel up to a specified central deflection. In ASTM C 1550 test method, the energy absorbed up to a specified central deflection is taken to represent the ability of a fiber-reinforced concrete to redistribute stress followed by cracking. 

The specimen dimensions of  the panel are 75 mm in thickness and 800 mm in diameter and the fixture supporting the panel during testing shall comprise any configuration that includes three symmetrically arranged pivot points on a pitch circle diameter of 750 mm.

The energy absorption considered between the beginning of loading and the specified central deflection. It is the area under the load-net deflection curve between the origin and the specified central deflection. Toughness test (ASTM C1550) usually expressed at central deflections of 5, 10, 20, or 40 mm.

Sample size:

To tesTo test in accordance with ASTM C1550, the size of specimens should have a diameter of 800 mm (31.5 in).

Data:

The Data stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.