During nighttime paving operations, what type of tack is typically used?

Using PG 52-28 or an approved emulsion as tack during nighttime paving operations is beneficial for several reasons. This choice combines the properties of a polymer-modified binder with the advantages of an emulsion, providing better adhesion between layers of asphalt.

During nighttime operations, ambient temperatures are generally lower, which can affect the performance of tack materials. PG 52-28, being a polymer-modified grade, maintains better workability and adhesion at these cooler temperatures compared to other options. The use of an approved emulsion enhances this by providing a consistent distribution of the tack, which is crucial for ensuring that the new asphalt layer bonds effectively to the already laid surface, even under variable nighttime conditions.

Additionally, utilizing an approved emulsion can help mitigate complications that may arise from temperature fluctuations, ensuring that the paving process remains uninterrupted and that the overall quality of the asphalt mat is maintained. This makes it a more reliable choice compared to conventional tack without modification, which may not perform as well under cooler nighttime conditions. Preference for water-based or oil-based products alone fails to address the specific requirements for nighttime paving, such as temperature stability and bonding capabilities.