The cracking problem of mortar in high-speed railway bridge bearing.

[Roy]

The formula mainly includes pure Aluminium sulfate cement, washed and dried river sand, water reducing agent, expanding agent, defoaming agent, lithium sulfate, and retarder. I just returned from the project, and there are cracks; the test temperature is 18 ℃. There is no problem with strength, fracture resistance, or initial and final coagulation. However, the construction temperature is 5°C and will not condense within 2 hours, and large cracks appeared. How can such a situation be avoided or solved?

 

[Cassie]

First of all, there is a problem with your system. The pure sulfur-aluminum system will have issues with strength stability in the later stage. The volume collapse is inevitable. Secondly, the influence of temperature is also significant. Low-temperature conditions will reduce cement's hydration rate, thereby affecting cement's strength development. So it would help if you increased its early strength; it is recommended to adjust the existing system, and remove the expanding agent.

 

[Scott Kaplan]

Besides, is adding pure Aluminium sulfate not afraid of the strength shrinkage in the later stage?

 

[Chanliss]

I assume it is plastic cracking.

 

[Luis]

There is a problem with the formula system, and the design is unreasonable.

 

[anna]

Recommend that you adjust the system's setting time to ensure the strength of 2 hours and then observe the cracks; you can also consider whether the grouting material has not been congealed for a long time and the reason for the water loss on the surface in the windy season.