用硅灰配制高抗折混凝土的研究

Research on the Effect of Silica Fume on the Performance of the Concrete with Higher Bending Strength

研究目的:提高铁路桥梁的跨度和耐久性是高性能混凝土研究的主要方向,硅灰和超细矿渣粉是配制大跨度预应力铁路桥梁最好的活性火山灰质材料。本试验研究的目的是通过在混凝土配料中加入等量硅灰代替矿渣水泥来提高混凝土的抗折强度和耐久性。研究结论:试验结果表明,掺加8%的等量硅灰代替矿渣水泥配制的高抗折混凝土的抗折强度3 d达到了8.8 MPa,提高了44.3%,28 d达到了11.4 MPa,提高了50.0%;掺硅灰的混凝土试样ZR-2的耐卤盐溶液侵蚀性能、抗碳化性能、抗冻融性能和抗渗性能也明显优于混凝土对比样ZR-1。根据试验研究结果可知,掺加8%的等量硅灰代替矿渣水泥可以配制耐久性良好的高抗折混凝土。

Research purposes： To increase the span and improve the durability of the concrete railway bridge is the main direction of the research in the high performance concrete, while the pre - stressed concrete is the mainly used one. In the mix bathing of the high - pre - stressed concrete, used in the construction of large - span pre - stressed concrete railway bridge, silica fume and super slag fines is the best active pozzolana. The purpose of this experiment is to improve the bending strength and durability of the concrete, and the approach is to replace the slag cement with the same amount of silica fume. Research conclusions ：The results of the experiment are as follows： the bending strength of the concrete with 8% of the slag cement substituted by silica fume is 8.8 MPa at the three - day age, increased by 44.3 %, while it is 11.4 MPa at the twenty eight - day age, increased by 50.0% ; some properties of the sample ZR - 2, adulterated with silica fume, are dramatically prior to the sample ZR - 1, such as the corrosion - resistant properties of brine salt solution, anti - freeze - thaw performance and anti - permeability performance. According to the data of this experiment, we could assert that with 8% of slag cement substituted by isometric silica fume, the high - bending concrete with good durability could be achived