关键词: 珊瑚砂;偏高岭土;氯离子扩散系数;干燥收缩

Abstract: Due to the high water absorption of coral sand aggregate , which can influence its strength development , also has bad influence on its durability .As commonly known , the addition of mineral admixtures can improve the properties of concrete .Hence, this study investigates the influence of 15wt％fly ash (FA), 15wt％ blast furnace slag (GGBS) and 5wt％ metakaolin (MK) on the mechanical properties, chloride permeability and drying shrinkage of CSC .In addition, the intrinsic mechanism and microstructure development of CSC are characterized by X-ray diffraction ( XRD) and scanning electron microscopy ( SEM) .The obtained results show that the combination of MK , GGBS and FA can optimize the hydration products and microstructure of CSC .Added mineral admixtures in CSC with different combination solution , the compressive strength increased by 17.7％-21％at 28 d, its chloride ion diffusion coefficient and drying shrinkage are reduced by 66.7％-71.0％and 36.7％-57.0％, respectively .

Key words: coral sand;metakaolin;chloride diffusion coefficient;drying shrinkage