摘要
有关掺纳米二氧化硅混凝土的力学性能和纳米二氧化硅对过渡界面微观结构的改善等方面,已经有了较为明确的结论,但是纳米二氧化硅对混凝土自收缩的影响鲜有报道。采用安明等人提出的测试方法,通过试验研究了纳米二氧化硅掺量(0、3%、5%)、水胶比(0.25、0.34)和引气剂(0、0.015%)水平对混凝土自收缩的影响。试验结果表明:(1)掺入纳米二氧化硅会提高混凝土的自收缩应变,在初凝至1 d龄期之间尤为明显;(2)水胶比对混凝土的自收缩影响非常大,水胶比越低,混凝土的自收缩越大,初凝至1 d龄期内的自收缩占28 d自收缩的比例越大;(3)引气剂能够明显地降低混凝土在各个龄期时的自收缩应变。
Mechanical performances and the improvement of intertransition zone microstructure of concrete with Nano SiO2 have been separately studied, and there are some conclusions are acceptable. Nevertheless, the influence of Nino SiO2 on concrete autogeneous shrinkage is not familiar to some researchers. The concretes with different levels of Nano SiO2 content （0,3%, 5%）, the water to binder ratio（0.25,0. 34）, and air entraining agent content（0,0. 015%） are experimented with the testing method proposed by An M Zand etc. in present paper. The experimental results strongly suggest that the addition of Nano SiO2 can increase the autogeneous shrinkage of concrete, especially in the early age （from the initial setting to 1 day age）. Meanwhile, the influence of water to binder ratio on the augenous shrinkage is pretty great, decreasring the water to binder ratio resulted in the increasing of the autogenous shrinkage of concrete, the lower of the water to binder ratio the larger percentage of early autogenous shrinkage （from the initial setting to 1 day age ） to 28 days＇. Finally, the autogenous shrinkage of concrete can be reduced sharply with the addition of air entraining agent.
出处
《公路》
北大核心
2006年第10期175-180,共6页
Highway
关键词
纳米二氧化硅
高强混凝土
自收缩
nano-SiO2
high strength concrete
autogeneous shrinkage
