机制砂混凝土泵送技术

Study of the Pumping Technique for Concrete with Machine-Produced Sand

机制砂混凝土多用于交通不便或资源有限的山区,因机制砂自身特性加之级配不良,混凝土易发生离析泌水等现象,质量很不稳定,对其泵送工艺进行研究:混凝土用材料及配合比方面,改善其工作性能;合理选择砼输送管,尽量减少输送距离及输送带来的压力;布管合理,根据向上、向下或者水平泵送等不同的泵送要求,选择合适的管路布设方式;在出现堵塞管路时,采取恰当的方式进行排除。结合老鹰岩特大桥126 m高墩泵送混凝土施工过程,通过对生产环节进行控制,生产的混凝土内实外美,效果良好。

Concrete with machine-produced sand is mostly used in mountainous areas where traffic facilities are very poor and natural resources are limited.Owing to the characteristics of the machine-produced sand itself and the poor gradation,concrete is prone to suffering from such phenomena as maceration or dehydration,as a result of which the quality of concrete will be very unstable.To solve the problem,the pumping process is studied in detail,upon the basis of which it is found that the materials to be used for concrete and the mix ratio have to be modified so as to improve the performance of concrete;the pumping pipes have to be rationally chosen so as to minimize the conveying distance and the conveying pressure;pipelines have to be rationally laid out,by which it is meant that the appropriate distribution ways of the pipeline have to be chosen according to the specific pumping requirements,such as upward,downward or horizontal conveying;in the event of pipe blockage,proper methods have to be adopted to unclog the pipeline.With the concrete-pumping operation for the 125m-high piers of the Laoyingyan Mega Bridge as a practical example,all the production links being strictly controlled,the concrete produced is internally solid and externally beautiful,as a result of which very good effects are achieved.