With cold weather on its way, asphalt contractors should know how to ensure their operations are successful when the cold weather and snow finally arrive. More importantly, they must know how to maintain quality asphalt paving in these harsh conditions.
Quality of asphalt pavement refers to the degree of compaction achieved. Effective compaction is the key element in placing quality asphalt pavement that will perform well for many years.
Studies and field experience have proven that paving can be done under these adverse weather conditions. The key to success during the winter months is understanding that paving practices that are successful in the summer, will not have the same results in October through April.
Additionally, the temperature of hot mix asphalt (HMA) during the rolling process is what determines the quality of compaction. Mix temperature is directly related to the compaction of HMA.
HMA is made of rock, sand, and asphalt cement (binder). The binder is the glue that holds the rocks together to make up hot mix asphalt. Asphalt cement has different thicknesses at different temperatures. Thinner asphalt cement “flows” more easily.
Warm Mix Asphalt (WMA) is a newer technology created to allow producers of HMA to lower temperature at which the material is mixed and placed on the road. This new innovative technology reduces paving cost, extends the paving season, improves asphalt compaction, allows asphalt mix to be hauled longer distances, and improves working conditions by reducing exposure to fuel emissions, fumes, and odors.
For all paving projects, it is critical that the asphalt cement is above the minimum temperature at which it will flow sufficiently for quality compaction to be obtained. The cold weather makes it challenging to maintain the mix temperature from the plant to the rollers.
If the asphalt cement can flow easily, the rollers can force the mix into a compacted and stable configuration. When asphalt cement is thicker and does not flow easily, the temperature drops and it behaves more like glue; the force of the rollers cannot manipulate it into a compact surface.
Mix temperature is, by far, the single most critical factor in achieving sufficient compaction under the weight of the rollers, especially in the cold weather.
Crisdel is fully equipped to pave during all seasons. We have a firm understanding of how the “flow” of asphalt cement affects the quality of compaction. Please feel free to contact us all year round for your asphalt pavement needs.