Cape Seal Road Treatment Weather Requirements

Weather plays an extremely important role in cape seal operations.  Ideal conditions for the chip seal treatment part of the cape seal treatment are:

• Air and surface temperatures are above 60F and rising for emulsified asphalts and 70° F (21°C) and rising for asphalt cements
• Humidity is 50 percent or lower
• Little to no wind
• No rain in the forecast

Weather is equally important in slurry seal/micro surfacing operations. Ideal conditions for the slurry seal/micro surfacing portion of the cape seal treatment are: 

• Slurry seal/micro surfacing should be applied when both pavement and air temperatures are above 45°F (7°C) and rising.
• While the application of slurry seal/micro surfacing should be suspended if rain is imminent, newly applied slurry seal/micro surfacing can resist a certain amount of rain.

Unsuitable conditions for chip seal portion of the cape seal construction:

• Cool nights make it very tough for chip seals to cure or gain strength.  This is why there are usually seasonal limitations on chip seal construction.
• Strong wind can distort the fan pattern of the asphalt being sprayed which could lead to streaking and uneven distribution.  An apron can be installed around the spray bar to minimize the effects of wind if necessary.
• High humidity can lead to longer break times for emulsified asphalts.
• Saturated roadways can lead to longer break times due to water still being in the roadway.
• Rainfall could lead to asphalt running off the roadway which could lead to rock loss.

Unsuitable conditions for the slurry seal/micro surfacing portion of cape seal construction:

• Micro surfacing should not be performed when either the pavement or air temperature is below 50°F (10°C) and falling. 
• Micro surfacing should not be performed if there is a possibility of freezing temperatures within 24 hours of application.
• The mixture shall not be applied when weather conditions prolong the opening to traffic beyond a reasonable time.