What is the low end ambient air temperature for FC-5 asphalt?

The low end ambient air temperature for FC-5 asphalt is 65°F unless the engineer approves use at 60°F. This guideline is crucial because it helps ensure that the asphalt mixture performs optimally during installation and subsequent use.

Temperature impacts the workability, compaction, and adhesion properties of the asphalt. At too low of a temperature, the asphalt can become too stiff, making it difficult to compact properly and potentially leading to numerous performance issues such as cracks and reduced service life. The allowance for an exception to use at 60°F with engineer approval is important as it provides flexibility in situations where the ambient temperature may dip slightly below the optimal threshold, yet still ensures that the decision is made by a qualified professional familiar with specific project conditions and requirements. This approach balances standard practices with practical considerations in real-world applications.

Other temperatures mentioned in the choices do not align with standard practices for FC-5 asphalt. The specified guideline prioritizes quality and performance while allowing for professional adjustments based on unique circumstances.