Abstract: Strength characteristics of plastic concrete have been investigated in this study using conventional triaxial compression tests under low confining pressure for different mix ratios of bentonite and cement. According to the Mohr-Coulomb strength theory, the peak strength of plastic concrete under low confining pressure were used to derive four typical intensity parameters of plastic concrete: uniaxial compressive strength, cohesion, internal friction angle, and tension-compression strength ratio. The results show that as bentonite-cement mix ratio increases, cohesion and uniaxial compressive strength decrease significantly and peak strain increases, while internal friction angle and tension-compression strength ratio change insignificantly. This indicates little effects of the mix ratio on the sensitivity of plastic concrete strength to hydrostatic stress or on tension-compression strength ratio.