高性能流态混凝土在公路改扩建施工中的应用

Application of High Performance Fly Ash Fluid Concrete in Highway Reconstruction and Construction

针对改、扩建公路施工拼接部位构件截面小、钢筋布置密集、混凝土拌合物不易振捣的情况。以G15沈海高速江门~开平段拓宽施工中应用了高性能粉煤灰流态混凝土为例。使用硫化物类外加剂以及在胶凝材料中添加粉煤灰等措施设计混凝土配合比,以提高混凝土拌合物各项工作性能,从而实现混凝土自密实功能,解决了小截面构件钢筋密集区域混凝土拌合物不易振捣问题。实践表明:合理使用硫化型外加剂和粉煤灰可制备出具有自密实功能,坍落度经时损失小的高性能粉煤灰流态混凝土。对高性能粉煤灰混凝土配合比设计和各项设计指标验证检测进行技术分析和总结。应用在实践中,对提高公路改、扩建施工中小截面构件混凝土施工质量具有一定的意义。

Aiming at the small and small sections of the joints of the road construction and the expansion of the steel bars,the concrete mixture is not easy to vibrate. Taking the high-performance fly ash fluid concrete in the widening construction of G15 Shenhai Expressway Jiangmen-Kaiping section as an example,design the mix ratio from the use of sulfide-based admixtures and the addition of appropriate amount of fly ash to the cementitious materials. Improve the work indexes of concrete mixture,so as to realize the self-compacting function of concrete,and solve the problem that the concrete mixture in small-section members is not suitable for vibration. The practice shows that the use of vulcanized admixture and fly ash can produce high-performance fly ash fluid concrete with self-compacting function and small loss of slump. Technical analysis and summary of high-performance fly ash concrete mix design and various design indicators. In practice,it has certain significance for improving the concrete construction quality of small and medium-section members in the reconstruction and expansion.