Chemical soil grout gel time

[eric1037]

Does anyone know the proper method of measuring gel time for chemical grout?

The only thing I can find is

ASTM D 2471 Standard Test Methods for Gel Time and Peak
Exothermic Temperature of Reacting Thermosetting
Resins.

I'm not sure if this is the correct procedure for soil grouting though.

 

[BigHarvey]

Depends on type of chemical grout and reactive agent used. You are normally able to adjust setting time to your needs by modifying grout composition.
If you are usingsodium silicate with sodium bicarbonate or 600 series reactive agent, I can provide you with the formula. otherwise you will have generally to refer to reactive agent technical documentation.

 

[rchanke]

That is a good question and one I've asked myself over the years. I've always seen gel times to be a subjective measure as to when the grouting technician will determine what is and what is not the onset of gelling.

Working with sodium silicate permeation grouts, the time required to see gellation within the fluid matrix to the time at which the fluid is no longer visible and is replaced by soft gel, is minimal, but a minute or two. In terms of QA/QC and tracking gel times in the field one only hopes that there is consistency in who is determining/recording gel times thus enabling a correlation between gel time and consistency of batching methods.

Asides from grout recipe having an impact on gel times, as BigHarvey mentioned, you may see a very definite trend of gel time and time of day as it relates to ambient temperature. That is if you are working in an area with a significant temperature swing from day to night. I've seen gel times cut in half from cool early morning work to hot mid day operations.