Experimental Investigation On Mechanical Behavior Of Reactive Powder Concrete Under Tension-compression Stress State

Reactive Powder Concrete possesses ultra-high strength, tenacity as well as durability, which enables its promising future application in fields such as bridge projects, civil infrastructures, hydraulic structures, etc. In most engineering structures, concrete is subjected to multi-axial stresses. Therefore, in order to extend the application of Reactive Powder Concrete in engineering projects, it is of great importance to undertake experiment-based research on establishing specific constitutive model and failure criterion for it. Biaxial tension-compression test has been undertaken by the author to investigate the mechanical behavior of Reactive Powder Concrete and the main contents and conclusions are as follows:(1) Through conducting biaxial tension-compression tests in which varied constant compressive stresses are applied in the horizontal direction, stress-strain curves in the tensile direction have been obtained for Reactive Powder Concrete. Failure modes of the specimens are found to be related with the stress state and the process of degradation is analyzed.(2) The tensile strengths for Reactive Powder Concrete specimens under different horizontal compressive stresses are obtained from the biaxial test. The trend that peak tensile stress varies with the applied compressive stress is proposed.(3) The trends elastic modulus and peak tensile strain change as compressive stress varies are acquired from the stress-strain curve. A constitutive model in the tensile direction for Reactive Powder Concrete subjected to biaxial tension-compression has been constructed, in which damage constitutive model based on Weibull distribution is adopted in the upwards section and an expression from the concrete design codes is revised for the downward section.(4) Representative multi-axial strength data has been adopted to establish a specific multi-parameter failure criterion for Reactive Powder Concrete. Through introducing the stress ratio, the model can be simplified under biaxial stresses and an example of channel girder with no pre-stress in the transverse direction is adopted to demonstrate its application.