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The maximum aggregate size exhibits a substantial influence on many important characteristics of hydraulic concrete. This paper is dedicated to study the effects of coarse aggregate size by a series of experiments on full and triple graded Roller Compacted Concrete (RCC) mixtures, as well as experiments of full grade and wet screening on mechanics, deformation, thermotics and durability. The results show that full graded RCC with a water-binder ratio of 0.45-0.50 is acceptable for water consumption of 70kg/m^3, a sand ratio of 30% and a stone combination of 20:30:30:20. The full-graded large samples had compressive strength of 10% higher than that of wet-screened small samples, with however a considerable drop in tensile strength. The large aggregate had a more obvious function of restriction and restraint to the deformation of concrete, while full-graded RCC had better volume stability. The full-graded concrete samples preceded RCC small samples in terms of frost resistance. The impact mechanism of the coarse aggregate's maximum size mainly lied in the transformation of interface structure, and was also related to the characteristics of RCC. The full-graded RCC could further reduce the consumption of plastic materials, lower the temperature rise of hydration heat, simplify temperature control measures, reduce cracks and improve the characteristics of concrete, which is promising in both technical and economic perspectives.
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