【摘要】 以不同质量分数（3%、6%、9%和12%）的偏高岭土（MK）取代胶凝材料，制备了偏高岭土改性高强混凝土，通过XRD、SEM、力学性能测试、孔径分析及碳化测试等手段对混凝土进行了表征，系统研究了偏高岭土取代率对混凝土各项性能的影响。结果表明，偏高岭土取代率的增加促进了Ca（OH）₂的消耗，加速了钙矾石和C-S-H凝胶等水泥水化产物的生成，提高了混凝土的致密度及界面过渡区的强度。随着偏高岭土取代率的增加，混凝土的孔隙率和总孔面积逐渐降低，MK取代率9%的混凝土的孔隙率最低为13.31%,总孔面积最小为10.651 m²/g,平均孔径为17.3 nm,该取代比例的混凝土在28 d龄期时的抗压强度和抗折强度达到最大值，分别为44.5和6.3 MPa。在碳化28 d时，MK取代率9%的混凝土的碳化深度为最低值10.9 mm,相比未取代的混凝土试样，碳化深度降低了28.76%,抗碳化性能最优。更多还原

【Abstract】 In this paper, metakaolin modified high-strength concrete was prepared with different mass fraction（3%, 6%, 9%, 12%） substituted by metakaolin cementing material. The concrete was characterized by XRD, SEM, mechanical properties test, pore size analysis and carbonization test, and the effect of metakaolin substitution rate on various properties of concrete was systematically studied. The results showed that the increase of metakaolin substitution rate promotes the consumption of Ca（OH）₂, accelerates the formation of cement hydration products such as ettringite and C-S-H gel, and improves the density of concrete and the strength of interfacial transition zone. With the increase of metakaolin substitution rate, the porosity and total pore area of concrete gradually decrease. The porosity of concrete with 9% substitution rate reaches the lowest value of 13.31%, the total pore area is 10.651 m²/g, and the average pore size is 17.3 nm. The compressive strength and flexural strength of the substituted concrete at 28 d of age reach the maximum value of 44.5 and 6.3 MPa respectively. At 28 d of carbonization, the carbonation depth of the concrete with 9% metakaolin substitution rate is the lowest value of 10.9 mm, and the carbonation depth is reduced by 28.76% compared with the unreplaced concrete sample, and the carbonation resistance is the best.更多还原