纳米二氧化钛颗粒对混凝土力学特性的影响

EFFECT OF NANO-TIO_(2) PARTICLES ON MECHANICAL PROPERTIES OF CONCRETE

研究了纳米二氧化钛(TiO_2)颗粒对混凝土抗压、抗拉及冻融耐久性的影响,并利用颗粒流PFC 2D (Particle Flow Code, Two-dimensional)对普通混凝土与纳米颗粒改性混凝土进行常温下抗压和抗拉模拟。结果表明:纳米TiO_2颗粒能够改善混凝土的致密性,常温下3%掺量的纳米颗粒对其抗压性提高最明显,其相对普通混凝土抗压强度提高了20.18%;纳米颗粒对混凝土的抗拉性能基本无影响,但对混凝土的冻融性有很大的提高,100次冻融循环后其相对普通混凝土抗冻性提高了136.8%。PFC 2D能良好地模拟普通混凝土及纳米颗粒改性混凝土的抗压和抗拉力学特性,由于混凝土的离散型,模拟与试验应力应变趋势上有微小的差异,但能较准确反应其峰值应力和应变。

The effect of nano-TiO 2 particles on the compressive,tensile and freeze-thaw durability of concrete was studied,and the normal concrete and the nano-TiO 2 concrete were simulated at room temperature by PFC 2D.The results showed that the nano-TiO 2 particles could improve the compactness of concrete,at room temperature,3%nano-TiO 2 particles had the most improvement in concrete compressive strength,which was 20.18%higher than normal concrete.The tensile performance of nano-TiO 2 concrete was unchanged,but the freeze-thaw resistance of nano-TiO 2 concrete had been greatly improved.After being subjected to 100 freeze-thaw cycles,its freeze resistance increased by 136.8%compared to normal concrete.PFC 2D could well simulate the compressive and tensile mechanical properties of normal concrete and nano-particle modified concrete.Due to the discreteness of concrete,there was a slight difference between the simulated and experimental stress and strain trends,but it could accurately reflect its peak stress and strain.