纳米高岭土颗粒改性水泥基复合材料的性能

研究了纳米高岭土颗粒对不同龄期水泥基材料微观结构（微孔结构、微观结构）及物理力学性能（工作性、抗弯强度、抗压强度、氯离子渗透性）的影响。结果表明，纳米高岭土颗粒的填充效应及其对水泥水化的促进作用改善了水泥基材料的微观孔结构，限制了氯离子在水泥基材料中的渗透扩散。当高岭土为水泥质量的1％时，水泥浆1、3、7、90 d抗弯强度分别提高30．41％、39．04％、36．27％和38．32％；当高岭土为水泥质量的5％时，水泥砂浆氯离子扩散系数降低53．03％；混凝土氯离子扩散系数随高岭土掺量增加呈指数递减；当高岭土为水泥质量的5％时，氯离子扩散系数降低18．87％；抗压强度分别提高28．4％；改性混凝土28 d抗压强度与混凝土氯离子扩散系数呈线性增加关系。

Mechanical and Chloride Diffusion Behavior of Kaolinite Clay Modified Cement-Based Material

T he effects of kaolinite clay on the microstructure （pore structure , internal structure ） and mechanical properties （workability ,early-age and long-term flexural strength ,chloride diffusion property ） of the cementitious composites were tested .It is shown that the addition of clay improves the micro-pore structure in the cement paste and limits the introduction of chloride ions .As a result ,it is suggested that the kaolinite clay would act as both filler and accelerator of cement hydration .Compared with the control specimen ,the flexural strength of cement paste with 1% kaolinite clay increased by 30 .41% ,39 .04% , 36.27% and 38 .32% at 1 ,3 ,7 and 90 curing ages ,respectively .The 28-day flexural strength increased slightly .It is observed that the clay modified cement mortar has lower chloride diffusion coefficient values compared to the plain mortar ,and the 28-day DCl of cement mortar decreased by 53 .03% with 5% clay . Compared with the controlled sample ,the increase in compressive strength and the reduction in chloride diffusion coefficient of the concrete with 5% clay addition is 28 .4% and 18 .87% respectively .The chloride diffusion coefficient of concrete decreases with the amount of clay addition exponentially . The 28-day compressive strength increases linearly with the chloride diffusion coefficient of the concrete .