Dimensional stone used in the construction industry requires flexural strength testing. ASTM C880, the standard test method for flexural strength of dimension stone,
details the test specimens and fixtures required to determine flexural strength.
The requirements of ASTM C880 include the following machine specifications and specimen preparation:
Equipment - A testing machine capable of withstanding compressive loads as well as a 4-point loading fixture.
The fixture includes bearing support blocks to ensure vertical loading of the dimension stone specimen.
The span length and distance between the load and support blocks must be constant within ± 0.05 inches
Test Specimens - Specimens are sawn and ground to 4 inches x 1.25 inches x 15 inches. The planes perpendicular to the load require fine grinding,
while all other planes require fine sawing. A minimum of five specimens are tested for each specific test condition.
Measurement Specimens - The lower support span is 12.5 inches and the upper support span is set to 6.25 inches.
Conditioning - Dimensional Stone can be tested in both dry and wet conditions
Dry specimens are conditioned at 140 ± 4º degrees Fahrenheit for 48 hours
Wet specimens must be immersed in water at 72 ± 4º degrees Fahrenheit for 48 hours
To test flexural strength, we selected an Industrial Series Hydraulic Universal Testing Machine with compression capabilities only.
The machine includes an adjustable crosshead with mounting features for mounting and centering the upper portion of the flexure test fixture.
In addition, the machine includes a workbench that allows the lower portion of the fixture to be centered. lixian designed the required fixture to provide
two lower supports (1 inch diameter) and two upper load application blocks (1 inch diameter) for 4-point loading per ASTM C880 specifications.
