Grout can be safely placed through the summer months in hot, dry climates if certain precautions are taken. Hot weather is defined by the American Concrete Institute as, "a period when for more than 3 successive days the mean daily temperature is above 90°F." In order to apply grout in hot weather conditions, the following precautions must be followed:
1. Normal cement storage and handling practices should be observed. Store material indoors or in the shade with the plastic shrink-wrap removed. Use water cooled with ice, if needed. A fine screen can be used to filter out the ice when pouring the mix water.
2. Prior to grouting, it is crucial to keep the grout base saturated with water (SSD) for 24 hours in advance. The metal base plate should be cooled. If possible, create shade for the area to be grouted.
3. Begin grouting during the early part of the day to take advantage of the cooler temperatures.
4. During pumping applications, keep the pumping lines cool, especially with long lines. Use as little line as possible. Also, prior to priming the pump with cement slurry, pumping cold water through the lines will cool the lines down.
5. Mixing water shall be kept at a temperature of 30°F to 50°F.
6. Hot weather will reduce the working time with the grout and smaller batches may be required. The compressive strength of the grout may be tested according to ASTM C109. Use a surface thermometer to monitor temperature conditions of the grout.
These tips were provided by US SPEC, maker of non-shrink grouts formulated to meet the requirements of ASTM C1107, CRD C-621 Corps of Engineers, and various DOT Specifications.