Hot & Cold Weather Masonry Construction
Material Heating
General. Heating mixing water is typically the easiest and most cost effective method of increasing mortar and grout temperatures. Heating only the water will be satisfactory if the other construction materials are unfrozen. Water may be heated using a 55-gallon drum with a fire or heat source below, or with immersion heaters, flame guns, or steam probes. Any method that does not add deleterious matter to the water is acceptable. This mixing water should be heated sufficiently to produce mortar temperatures between 40°F (4.4°C) and 120°F (48.9°C). Once a mortar temperature has been selected in this range, every effort should be made to maintain this temperature for consecutive batches.
Heat masonry sand when the temperature of the sand is below 32°F (0°C). A simple method for heating sand for mortar is to heap sand over a section of a large diameter pipe (such as a culvert or smokestack) in which a slowburning fire is built. Any device that allows the thawing of the ice without scorching the sand is satisfactory. Whenever wood fires are used for heating the sand, care should be taken to prevent the wood ash from contaminating the sand and mortar.
When the temperature of dry masonry units is below 20° F (-6.7°C) they should be heated so they are above 20°F (-6.7°C) at the time of their use. Wet frozen masonry units should be thawed without overheating. These heating requirements prevent rapid cooling of the heated mortar as it comes into contact with the masonry unit. Even when the temperature is above 20°F it may be advantageous to heat the units for greater mason productivity.
Summary. As the temperature falls below normal, the total number of construction materials requiring heating increases. Water is the most logical first material to heat. Masonry sand will have to be thawed, if frozen, and may have to be heated additionally to produce mortars with the desired temperature.
Wet, frozen masonry units must be thawed. Dry units, colder than 20°F (-6.7°C) should be heated, being careful not to overheat them.
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