Quality Control During the Grouting Process of Hollow anchor bolt

Hollow anchor bolt combines drilling, grouting and anchoring together, which has played a great role for the stabilization of projects. Grouting effect concerns with structure’s stability and it should be control strictly.
1. Controlling concrete slump.
Concrete slump has direct influence for the quality of pile construction. The standard concrete should be mixed uniformly, with good workability, small internal resistance, long initial setting time, good lubricity and good thixotropic performance, only this, it can effectively guarantee the concrete pouring, continuity and compactness.
To formulate the reasonable slump of concrete and to ensure the quality of pile body, supervisors must pay attention to the following points:
①The raw materials for making concrete must conform to the requirements, especially the cement quality;
②The mixing proportion of concrete should be determined through experiments;
③Carrying out the quality control work of concrete mixing at the scene and strictly accordance with the mixture of feeding;
④Arranging someone to inspect concrete slump and other indicators.
2. The embedded depth control.
The depth of hollow anchor bolt is related to the quality of project. During the process of grouting, actual elevation of concrete surface should be often measured, lifting height should be calculated, relative location between anchor bolt and concrete surface should be controlled. Generally, the depth of hollow anchor bolt should control between 2~6 meters, otherwise, different forms of problems will appear and they will influence projects’ integral quality.
3. Reinforcement cage up-floating control.
Before grouting concrete, the gravity of reinforcement cage forms balanced state with suspension force. But there are also some reasons arousing its up-floating: ①Weak fixed at orifice; ②Large amount of grouting concrete; ③Bad quality of concrete. The methods are not only operating correctly, ensuring good concrete quality, but also supervising all the time.
4. Pile head control.
During the construction of drilling, grouting and pile hacking & cutting, if pile head quality wants to be controlled, the last grouting amount should be controlled, head should not be made low and exposed concrete should reach designed intensity value. While in actual operation, improper control of grouting amount, impurity concrete and hole cleaning not thoroughly all will have influence on quality of construction.