An experimental investigation on the variation of compressive strength, splitting tensile strength and fracture energy, with the ratios of water to binder (W/B) of ultra-high strength concretes, including the reactive power concrete (RPC) and ultra-high strength concrete with coarse aggregate (UHSC), has been carried out.The W/B varied between 0.14 and 0.22 at a constant increment of 0.02.It was observed that,compressive strength of RPC almost remained the unchanged, when the W/B was between 0.14 and 0.18.However, it decreased dramatically when the ratios were 0.20 and 0.22.For UHSC, the compressive strength was the highest value at the ratio of 0.18.The results of the two concretes could not comply with the Abrams generalized W/B ratio law.Moreover, splitting tensile strength of RPC and UHSC decreased continually as the ratio increased firom 0.14 to 0.22.Fracture energy of RPC was more or less the same when the ratios were between 0.16 and 0.20, and the maximum value was at 0.14.Fracture energy was observed to be almost no variation for UHSC at all ratios.