Experimental study on mechanical behaviors of pseudo-ductile cementitious composites under biaxial compression

Abstract

Experimental investigation was conducted to characterize the responses of pseudo-ductile cementitious composites (PDCCs) when subjected to uniaxial and biaxial compression. The PDCCs is a class of fiber reinforced cementitious composites with ultra-high ductility by using a low volume fraction (2%) of polyvinyl alcohol (PVA) fiber. Two different strength grades of PDCC were examined with cubic specimen size of 100 mm in the tests. The specimens were loaded with a servo-hydraulic jack at different stress ratios. The principle stresses and strains of the specimens were recorded, and the failure modes with various stress states were examined. The test results indicated that the ultimate strength of PDCCs increased due to the lateral confinement in the other principal stress direction, and the maximum ultimate strength occurred at the biaxial stress ratio of 0.25, which was very different from common concrete material. For the PDCC specimens, the biaxial strength may be lower than the uniaxial strength when subjected to biaxial compression with the stress ratio of 1.0, and the failure mode showed a shear-type failure because of the bridging effect of fibers. Finally, a failure criterion was proposed for PDCCs under biaxial compression.