河套灌区渠道衬砌混凝土的纳米颗粒改性研究

Study on Nano-particle Modification of Canal Lining Concrete in Hetao Irrigation Area

为了改善河套灌区大量渠道衬砌工程中混凝土的干缩变形性能,采用纳米二氧化硅(NS)和纳米碳化硅(NC)掺入粉煤灰水泥砂浆制备混凝土试样,并对其作用机理进行理论分析。结果表明,纳米颗粒在提高粉煤灰混凝土抗压和抗弯强度得同时也改善了干缩性能;与普通水泥砂浆相比,单掺2%NS和单掺2%NC的水泥砂浆干燥收缩率分别提高了约90%和120%;改性干缩率在早期增加明显,单掺与双掺对混凝土的干缩率影响差异不大;纳米颗粒的表面效应和微观骨料填充效应,增大了骨料得表面能且填充了内部孔隙,是干缩性能有明显提高的原因。研究结果对设计高强度和高干缩性的衬砌混凝土,提高河套灌区渠道使用寿命具有一定指导意义。

In order to improve the dry shrinkage deformation performance of concrete in a large number of canal lining works in Hetao irrigation area,two types of nano-particles,including nano-silica( NS) and nano-silicon carbide( NC),were used to prepare concrete specimens. On the basis of strength tests,the effect of nano-particle content on the drying shrinkage performance of different specimens was studied,and the mechanism was analyzed theoretically. The results show that nano-particles can improve both the compressive and bending strength of fly ash concrete,so as the drying shrinkage performance. The optimum adding quantity of NS and NC is 2% and 2% with the drying shrinkage rate of drying enhanced by 90% and 120% respectively. The dry shrinkage rate is significantly increased in the early stages,and the effect of single and double mixing on the dry shrinkage of concrete are not very different. The surface energy of aggregate is increased and the micro-structure pore is filled,so the drying shrinkage performance of fly ash concrete is improved based on the surface effect of nano-particles and micro-aggregate filling effect. The research results have certain guiding significance for designing high strength and drying shrinkage performance of concrete in Hetao irrigation area.