纳米MgO对高强水泥基材料力学与收缩性能的影响

橡胶砂浆的强度会随着橡胶掺量的增大而降低,限制了其工程应用。为增大橡胶掺量,补偿橡胶掺量过大带来的强度损失,以纳米SiO_2作为橡胶砂浆强度提升的外加剂,以橡胶替代率为40%和60%等体积替代砂子,共设计了6种配合比。研究了一定量的纳米SiO_2对两种大掺量的橡胶砂浆强度的提升以及收缩性、密度及孔隙的影响。结果表明:纳米SiO_2对大掺量砂浆抗压、抗折强度均有显著的提升;且提升效果优于普通砂浆。掺入纳米SiO_2可增强橡胶砂浆的刚度;并且使其韧性仍优于普通砂浆。掺入纳米SiO_2能够减少大掺量橡胶砂浆的孔隙率和吸水率。并且使橡胶砂浆的密度增加;橡胶掺量对砂浆的收缩量影响不明显;而加入纳米SiO_2会使橡胶砂浆的收缩量增大。掺入纳米SiO_2能够减少橡胶砂浆的质量损失;并且橡胶掺量越大作用越明显。

Effect of nano-MgO on mechanical and shrinkage properties of high-strength cement base material

High-strength cement base material was usually show a lot of problems such as easy cracking and shrinkage properties. Therefore, high-strength cement base material was prepared by nano-MgO to analysis the modified effect of nano-MgO on mechanical properties and shrinkage properties of high strength cement base material.The results showed that: when the dosage of nano-MgO is bigger, the initial setting time and final setting time of high-strength cement base material is the shorter. The shorten quantity of final setting time is relatively large and liquidity reduced. 0.5%~4.0% nano-MgO can improve the compressive strength and flexural strength of high-strength cement base material, and the flexural strength is about 1/5~1/7 of the compressive strength. The flexural strength and compressive strength reached the maximum when the dosage is 1.0%. Drying shrinkage and mass loss of high-strength cement base material increased with the increase of dosage of nano-MgO continuously decreased, and there is a linear relationship between both. In conclusion, it found that nano-MgO can be modified high strength cement base material of workability, mechanical properties and shrinkage properties.