What is necessary for the tack coat application to bond properly?

For a tack coat application to bond properly, maintaining the proper temperature is crucial. The tack coat serves as an adhesive between layers of asphalt, and its effectiveness is significantly influenced by temperature. When applied at the correct temperature, the material achieves optimal viscosity, allowing it to spread evenly and adhere well to both the existing surface and the subsequent layer of asphalt.

If the temperature is too low, the tack coat may be too viscous, impairing its ability to bond effectively. Conversely, if the temperature is too high, the tack coat might evaporate too quickly, preventing adequate bonding with the surface. Thus, ensuring the tack coat's application occurs within the specified temperature range is essential for achieving a durable and lasting bond between layers in roadway construction.