Effect Of Nano-Materials On Durability Of Concrete

Concrete is one of the building materials widely used in civil engineering. When concrete strutures are exposed in severe environment, its performance becomes inferior, which decreases its durability and leads it to damage in advance. It has become a hot topic to study for the civil engineering to improve durability of concrete.Having special performances, nano-material was called new material in 21 st Century. Study on which nano-material was used to improve concrete performance was very little. Nano-materials will apply to more wide field with study of nano-materials and decrease of their cost and it bring hope for nano-materials to be used in high durability concrete and high performance concrete.Hydration of nano-SiO₂ and nano-CaCO₃ in cement paste were studied by XRD, SEM, TEM and EDXA. Microstruction of the concrete with nano-SiO₂ or nano-CaCO₃ were analyzed. Compositions of the cement paste with nano- CaCO₃ was investigated and it was presented that nano-CaCO₃ can baffle ettringite (AFt) transforming to Afm.The performances of concrete with nano-materials, Silica Fume and fly ash were investigated in the experiments such as compress strength, concrete chloride diffusivity, sulfate resistance and drying/wetting cycle in corrosive environments etc. Action rules and mechanisms of nano-materials on the concrete were analyzed and discussed. Content of the experiments was great and their terms were long enough such as 6 months sulfate resistance, 110 times (110d) drying/wetting cycle in corrosive environments and 180d chloride diffusivity. Experiment datum and hypotheses were supplied for using of nano-materials in concrete.A means which an anticorrosive mixture with nano-materials is used to improve durability of the concrete was given. Main Compositions and mix proportions were chosen based on behaviors of nano-materials and mineral admixtures (blending materials) in durability of the concrete as well as other domestic and international relational datum. The performances of concrete with the anticorrosive mixture were investigated in the experiments such as concrete chloride diffusivity, sulfate resistance and drying/wetting cycle in corrosive environments etc. It is very effective for concrete to improve concrete durability...