Technical requirements for grouting of prestressed pipes

The strength, fluidity, coagulation time, water leakage, expansion rate, gas content and other properties of the pore grouting slurry should meet the design requirements. When the design is not required, rightPrestressed concreteThe beam shall comply with the following regulations:

24h free water secretion rate 0, pressure water secretion rate; 24h free expansion rate 0 3%; Gas content 1% 3%.

Before the hole grouting is carried out, the grouting material used should be tested and verified in advance. Weighing of various materials should be accurate to 1% (all by mass). Water-glue ratio.

should not be exceeded. > compacted pipeline grouting.

The bridge carries not only its own life, but also the life of the people who move forward from it. It is found that many "short-lived" bridge collapse accidents have prestressed construction quality problems: first, they are applied to steel strands.

the prestress on deviates from the design requirements; Second, the grouting of the hole is not compact, and the prestressed mechanism cannot be effectively protected.

The repeated occurrence of "short-lived" bridges is not a problem of the prestressing technology itself, but due to the problems in the two key processes of tensioning and grouting in the prestressing construction, and no effective prestressing system has been established. Obviously, the "short-lived" problem of bridges is not called into question about prestressing, but about the quality of prestressed construction.

The above content reference: Encyclopedia - prestressed pipeline grouting

Summary. Dear Kiss I am happy to answer for you: how to calculate the grouting of prestressed pipesA:

Through the practice summary, the actual amount of grouting cement in the prestressed channel = the clearance volume of the prestressed channel (the cross-sectional area of the bellows minus the cross-sectional area of the steel hinge line and the length of the pipe). The amount of grouting cement in the prestressed channel has nothing to do with other admixtures. Hole grouting :

It usually refers to the use of cement slurry, mixed with external additives, before grouting with pressure water to flush the hole to be grouted, and then the cement slurry is pressed from one end of the hole, and the other end is closed after discharging the thick slurry. Increase the pressure to MPa for 3-5 minutes before finishing. Thank you for your patience.

The above is my full reply, if you are satisfied with my service, please give a thumbs up, and I wish you all the best! Peace and joy!

Kiss I am glad to answer for you: how to calculate the grouting of the prestressed pipeline Answer: Kiss Summarize the scattered staring through practice, the actual amount of grouting cement in the prestressed channel = the clearance volume of the prestressed hole (the cross-sectional area of the bellows minus the cross-sectional area of the steel hinge line and the length of the pipe).

The amount of grouting cement in the prestressed channel is not related to other additives. Hole grouting: It usually refers to the use of cement slurry, mixed with external additives, before grouting with pressure water to flush the hole to be grouted, and then the cement slurry is pressed from one end of the hole, and the other end is closed after discharging the thick slurry.

Increase the pressure to MPa for 3-5 minutes before finishing. Thank you for your patience. The above is my full reply, if you are satisfied with my service, please give a thumbs up, and I wish you all the best!

Peace and joy! How to calculate the number of grouting of corrugated pipe of prestressed box girder? Does it have anything to do with the water-glue ratio? What is the mass per cubic meter after the volume is calculated?

How to calculate the number of grouting of corrugated pipe of prestressed box girder? Does it have anything to do with the water-glue ratio? What is the mass per cubic meter after the volume is calculated?

Through the practice summary, the amount of grouting cement in the prestressed channel = the clearance volume of the prestressed channel (the cross-sectional area of the corrugated pipe minus the cross-sectional area of the steel hinge line and the length of the pipe). The amount of grouting cement in the prestressed channel has nothing to do with other admixtures. Hole grouting :

It usually refers to the use of cement slurry, mixed with external additives, before grouting with pressure water to prepare the hole to be grouted, and then the cement slurry is pressed from one end of the hole, and the other end is closed after discharging the thick slurry. Increase the pressure to MPa for 3-5 minutes before finishing.

The volume is calculated from the diameter and length of the bellows. Subtract the strand volume.

Strengthen the process control of bridge construction quality and eliminate quality defects in the construction process.

How to ensure the construction quality of the new bridge, how to carry out technical control of the new bridge, how to evaluate the quality of the existing bridge, and how to detect, evaluate and strengthen the dangerous bridge has become an important task. There are various forms of damage to concrete bridges, such as prestress loss, concrete damage and cracking, steel corrosion, support hollowing, etc., which lead to the decline of the overall stiffness and bearing capacity of concrete bridges, which is an important cause of bridge diseases. In order to strengthen the process control of bridge construction quality and eliminate the quality defects in the construction process, the grouting quality inspection of the prestressed pipeline (bellows) of the prestressed bridge is an important control link to ensure that the bridge construction quality meets the design requirements and the reasonable stress state.

The steel strand of the prestressed bridge should give full play to the design effect and offset the pressure of vehicles and pedestrians on the bridge deck, and the grouting quality effect of the prestressed pipeline is one of the most important factors. The grouting quality that meets the design requirements can make the prestressed steel strand fully function; When there are grouting quality defects, the anchor head stress concentration and prestress loss with time will occur, and the design stress state of the beam will be changed, and the bearing capacity of the bridge will be reduced, thereby affecting the service life of the bridge. Therefore, the grouting quality inspection of prestressed pipelines is an important measure to ensure the quality of bridge construction.

Generally, it is used for grouting after tensioning of prefabricated beams and fixing the tensioned wire rope.