Effects Of Nanoparticles Introduced Into The Material Properties Of Cement-Based Sol-Gel Method

Concrete has broad applicability and price advantage,has become the most important architectural structural materials,research shows that the incorporation of nanomaterials in concrete can significantly improve the mechanical properties and durability of concrete.Based on existing research on nano-silica and titania powders and sol as the raw material powder and mixed with fly ash to cement mortar and mortar, a comparative study of the different states of nanomaterials on the introduction of the cement influence and mechanism-based material properties. The results showed that:In this thesis, influence and mechanism of nano-silica dispersion on properties of fresh and hardened cement-based materials were investigated through incorporating nano-silica with different degree of dispersion by ball-milling the precipitated nano-silica with large agglomerates for different hours and also by adding superplasticizer as dispersant during ball-milling. The results showed that,(1) The introduction of nano-SiO2powder form has a certain effect on the fresh cement-based material flow, but little impact. Superplasticizer dosage is the same,0.5%doped nanoparticles that cause a certain degree of liquidity has decreased, but with content such as nanoparticles and water reducing the magnitude of the increase, cement mortar fluidity increased significantly; while introducing sol form nanoparticles have a significant impact on the cement mortar fluidity. Superplasticizer dosage is the same, mixed with0.5%sol cement mortar fluidity that leads to decreased; Even superplasticizer dosage and dosage synchronized nanoparticles increased dosage is large, still lead to decreased mobility cement mortar.(2) Doped nanoparticles contribute to the promotion of cement hydration, but its role in promoting and introducing nanoparticles form related. When introducing SiO2nano powder form, which promotes hydration obvious; when introduced in the form of a sol, although monodisperse nanoparticles state, and the ability to absorb calcium significantly better than NS, but to promote the role of hydration of cement is only slightly better in doped nano-SiO2powder, which is due to silica gel particles coated in cement layer is formed, resulting in the outward diffusion of ion hydration rate decreases, resulting in its role in promoting hydration of cement declined.(3) Doped nanoparticles can significantly improve the strength of cement mortar. When the nanoparticle content of less than1.0%, the sol morphology of nanoparticles to improve the strength of cement mortar better, when the nanoparticle content greater than1.0%is the opposite. Doped nanoparticles can significantly improve anti-neutral cement mortar, resistance to chloride ion penetration and carbonation resistance, and the introduction of nano-SiO2powder form is more conducive to improving the corrosion resistance of mortar and anti-carbonation properties, and the introduction of nano-SiO2sol form more help to improve cement mortar resistance to chloride ion penetration.(4) SEM, BSE and TG analysis showed that nanomaterials can promote cement hydration, improve the microstructure of cement-based materials. Ash effect was significantly higher than sol fine silica powder, which may also become a fine silica powder can better improve the performance of cement-based material determinants. MIP analysis showed that mixing NS, SS can effectively reduce the number of harmful hole, but the hole-doped NS to reduce harmful content more effectively, and to reduce low-density mixed SS amount of gel in the gel pore effect is not obvious, the reason for this is due to the smaller NS agglomerated particles can play filling effect, while the larger floc particles of silica in the form of cement hydration system, few can play the role filled.(5) The introduction of nano-SiO2powder form is more help to improve the anti-corrosion and anti-carbonation properties of hardened cement mortar reason may be due to the introduction of nano-SiO2powder form can be refined grains, and the form of the introduction of nano-SiO2sol resulted in cement-based materials in CH grain coarsening due.