Development and application of residual slurry recycling system of pipe pile by Tianjin Jiancheng Jiye Group Co., Ltd won the third prize of 2020 CCPA Concrete Science and Technology Award (Technology Innovation).

In pipe pile manufacture, a large amount of residual slurry is generated, and the discharge of residual slurry has become an industrial problem. In this project, wasted slurry has been converted into resources through recycling system. In this system, through stored and separated, wasted slurry could be used as raw material of pipe pile according to the different concentration. The utilization rate of residual slurry is about 95%. The installation of this system has the advantages of small investment, high income and short time consumption. There is no need to purchase new equipment. Just carry out systematic transformation on the the original slurry storage bucket for mass production successfully. In the production process, the concrete mix proportion is keeping updated, and the appropriate stability concentration value is determined through test and detection, so as to save the amount of cement in production.

The main innovations of the project are as follows.

l The residual slurry recycling system was developed.

The installation of residual slurry recycling system only needs the following transformations on the basis of the original slurry storage bucket. Retain the original slurry storage bucket, add connectors, and guide the slurry produced by centrifugation in the slurry storage bucket into storage through the fluidity and gravity of the slurry itself to collect the slurry. The raw slurry is stirred through the stirring blades to prevent the solidification and precipitation of the raw slurry. Through the intelligent control of the batching system, the raw slurry and water are prepared into slurry with different concentrations. The equipment and its operation are simple, and the utilization rate of residual slurry is about 95%.

l In the production process, the concrete mix proportion is keeping updated, and the appropriate stability concentration value is determined through test and detection, so as to save the amount of cement in production.

l To fully use the residual slurry in different concentrations, by analyzing the measured data of different pile types, different concentrations of raw slurry and diluted slurry of each concentration, the concentration is adjusted. Finally the appropriate stability concentration value is determined. The reference value of slurry-water mixing amount for concrete and the adjusted mix proportion are summarized, which saves the amount of cementitious materials.

The disposal of industrial waste has always been a social problem. How to deal with residual slurry is one of the key problems in the pipe pile industry. The recycling use of residual slurry challenges not only the mix proportion of concrete, but also the raw materials of concrete. The application of residual slurry recycling system provides great technical support for solving the problem of residual slurry treatment in pipe pile industry. Through the strict control of raw materials and the reasonable addition of residual slurry, the workability of concrete is stabilized and the production and construction is more efficient.