AvantiGrout BUZZ: Cold Weather Grouting
If you live in an area that often reaches temperatures below freezing for prolonged periods of time, then you are likely aware that colder temperatures and frozen ground can cause increased difficulty when grouting below-grade structures. This AvantiGrout BUZZ series topic dives deeper into injection grouting in the cold weather months.
- Temperature Effects on Cure Time - In short, temperature effects cure time of grout. A general rule of thumb for acrylics is for every 10°F drop in temperature, the cure time doubles; and for every 10°F rise in temperature, the cure time is cut in half. The chart below is an approximate example on temperature's effects of acrylics. There are ways to help increase material or batch mix temperatures such as using heat bands or warm water. The colder the temperature, the thicker material can get which increases viscosity and increases cure time. In regards to temperature effects on urethanes, the same rule of thumb does not apply. Temperature effects hydrophilics different than hydrophobics - hydrophobics have the ability to use less or more catalyst which helps slow down or speed up the reaction. Check the product's Technical Data Sheet for specific data on how cure time is affected by temperature or catalyst modification.
|Temperature||Cure Time (sec.)|
- Increasing the Amount of Catalyst - Urethanes - In injection grouting, catalysts are the products that 'start' the reaction of the grout. Not all grouts have a catalyst; some are strictly water activated or chemically activated, while others require additives to cure properly. Generally, all our hydrophobic grout systems require a catalyst exclusive to each grout. Ex. AV-276 Soilcat is the catalyst designed exclusively for use with AV-275 Soilgrout, and AV-279 Low Vis Accel is the catalyst designed exclusively for use with AV-278 Low Vis Hydro. Typically, one container of catalyst is mixed into a 5-gallon pail of grout and injected as a single component; it reacts with small amounts of moisture in the ground. However, depending on the desired reaction time, the catalyst may be cut in half or doubled. Cutting the catalyst in half increases the cure time, while doubling the catalyst lessens the cure time. Always perform the standard cup test with site water to determine if the desired reaction time has been met. To learn how modifying catalysts effects gel and reaction times, review Avanti’s Technical Data Sheets.
- Increasing the Amount of Catalyst - Acrylics - When it comes to chemically-activated grouts such as AV-100 Chemical Grout, you can also modify catalyst amounts to change the reaction time. Adding specific amounts of AV-101 Catalyst T+ to Tank A and AV-102 Ammonium Persulfate to Tank B will help speed up your reaction time. Always perform the standard cup test with site water to determine if the desired reaction time has been met. To learn how modifying catalysts effects gel and reaction times, review Avanti’s Technical Data Sheets.
- Using Optional Additives - There are many different optional additives that assist in the curing of grouts - specifically in colder weather projects:
- AV-105 Gel Guard - designed to reduce the freezing point of our chemically-activated and hydrophilic grouts. AV-105 also enhances compressive strength without reducing permeation capabilities. Adding 10% concentration can lower freezing temperatures by as much as 9°F/5°C.
- AV-255G Accelerator - used to speed the reaction time of our hydrophilic urethane grouts that do not utilize a catalyst - just water/moisture - such as AV-202 Multigrout and AV-315 Microfoam. Percent (%) of accelerator needed is based on the amount of five gallons of grout. See the Mix Procedure guideline calculations on the Technical Data Sheet as field conditions vary.
- AV-257 Icoset - low viscosity, gel strengthening agent (copolymer latex) typically used with our chemically-activated gel systems such as AV-100 Chemical Grout and hydrophilic gels such as AV-254 Gelseal. AV-257 has a freeze-grade rating, provides improved hydrostatic pressure resistance, better low-temperature plasticity, and improved adhesion to the cured material. Increases effectiveness of gel in the substrate matrix while not hindering permeation.