Q.: What can be done to speed up the setting time when working in weather that is cold, highly humid or a combination of both?
A.: Measures to shorten the setting time in cold weather are described in the answer to the next question. The effect of high humidity is to lengthen the period of time during which bleed water remains on the surface and delay the time when finishing can be done. It may be necessary to ventilate the area or heat it with vented heaters to promote evaporation.
If the highly humid conditions happen to occur when the weather is warm, the concrete may actually set before the bleed water has disappeared. Then if normal finishing practices were followed the concrete would become too hard to trowel long before the bleed water had evaporated. Under these circumstances it is necessary to remove the bleed water from the surface mechanically, for example by dragging a garden hose across the surface. When the surface is made sufficiently dry it can then be troweled.