Improvement of the biaxial flexure test method for concrete

The biaxial flexure test (BFT) method for the biaxial tensile strength of concrete has been improved. To ensure the equi-biaxial stress condition during the test, the geometry of the specimen, proper treatment of the specimen surface, and the support conditions were proposed. The biaxial flexural strength of concrete was measured with the improved biaxial flexure test method. The coefficient of variation (c.o.v) of the biaxial flexure test method is comparable to that of the four-point bending test and ASTM C 1550. The improved biaxial flexure test provides a practical and reliable means of determining the biaxial flexural strength of concrete. The biaxial tensile strength given by the biaxial flexure test method and the ASTM C 1550 method is greater than the uniaxial tensile strength using the four-point bending test method.