Cold Weather: typical precautions including adjustment of mix to reflect cold weather (warm mix water, accelerated mix) and protection of work area. Similar to formed wall construction, the fresh shotcrete needs to be insulated or heated to protect against freezing and to maintain temperatures required for design strength gain. In the absence of formwork to secure insulation to, heated enclosures or draped insulating blankets are used.
Hot Weather: typical precautions including adjustment of mix to reflect hot weather (cold mix water, ice, retarded mix) and protection of work area from direct sunlight. In addition to these precautions, curing may need to begin immediately following placement (if finishing is not immediately possible) and continued immediately following finishing. Evaporation reducers may be used to minimize surface evaporation prior to finishing. Micro fibers can also be added to reduce plastic shrinkage cracking in severe environments.