Did you know, when potholes pop up in winter, they are often treated with temporary, “throw and go” loose asphalt. This is because a more permanent repair requires that all loose debris and moisture be absent from the hole to allow the new filler to affix to the surrounding surfaces. In cold regions in the coldest months, asphalt plants also shut down because hot mix can’t be delivered and applied in time before the mix cools.
When using HMA (Hot Mix Asphalt) to fix a pothole the mix should be no colder than 185F when placed. This temperature is difficult to maintain when the outside temperature is cold. It also cannot be raining, snowing, or have any remaining moisture in the pothole; otherwise the patch will break because water breaks the HMA.
When using a cold patch material, it’s most often a water-based mix. This means the aggregates are held together by a bitumen-based water emulsion. When it rains it will dilute the emulsion and decrease the adhesion, breaking the patch. It also means your patch is sensitive to freeze-thaw weathering cycles. These cycles mean the water expands inside the patch when it freezes, and then seeps deeper into the patch when it melts. When the water infiltrates and begins to freeze, the area can swell and lift, which then can get caught by vehicles and plows, again breaking loose the patch. And repeat.