Should my Ottawa contractor use hot-mix or cold-mix asphalt?

Your Ottawa contractor should absolutely use hot-mix asphalt for any permanent driveway work. Cold-mix asphalt is only suitable for temporary repairs and will fail catastrophically in Ottawa's extreme freeze-thaw climate within one to two winters.

Hot-mix asphalt is heated to 140-160°C at the plant and delivered hot to your driveway in insulated trucks. This high temperature allows the asphalt binder to coat the aggregate completely and enables proper compaction with a steel drum roller while the material is still workable. Hot-mix cures into a dense, waterproof surface that can withstand Ottawa's brutal temperature swings from -30°C winters to +35°C summers. For Ottawa driveways, contractors typically use HL3 surface course (fine mix) for the top 50mm lift and HL8 binder course (coarser mix) for the structural base lift underneath.

Cold-mix asphalt is a completely different product designed for emergency pothole repairs and temporary patches. It's mixed with cutback oils or emulsions that allow it to remain workable at ambient temperature, but these additives prevent it from ever achieving the density and durability of hot-mix. Cold-mix compacts poorly, remains somewhat soft and porous, and allows water penetration. In Ottawa's climate with 50+ freeze-thaw cycles per winter, water enters the porous cold-mix, freezes and expands, then loosens the material. Cold-mix patches typically fail by spring, requiring constant reapplication.

Ottawa's extreme climate demands hot-mix asphalt because the material must withstand massive thermal expansion and contraction, heavy snow loads, aggressive plowing, and repeated salt exposure. The temperature differential of 60-65°C between winter lows and summer highs stresses asphalt relentlessly. Only properly compacted hot-mix asphalt has the density and flexibility to handle these conditions for 20-25 years with proper maintenance.

Timing is critical for hot-mix placement in Ottawa. The material must be placed when ambient temperatures are consistently above 10°C and rising, with base temperatures above 5°C. This limits the paving season to late May through early October in most years. Hot-mix cools rapidly in cold conditions, making proper compaction impossible. Asphalt placed too late in the season (October/November) risks not achieving full compaction before freezing, leading to raveling and premature failure.

Any contractor suggesting cold-mix for permanent driveway work should be avoided. This indicates either inexperience with Ottawa's climate or an attempt to cut costs with inferior materials. Quality paving contractors in Ottawa use hot-mix exclusively for permanent work, with proper base preparation (minimum 300mm Granular B sub-base plus 150mm Granular A base) and steel drum roller compaction while the asphalt is at proper temperature.

When hiring a contractor, verify they're using hot-mix asphalt delivered from a certified plant, confirm they have proper compaction equipment (steel drum roller, not just a plate compactor), and ensure they understand Ottawa's seasonal timing requirements. A properly installed hot-mix asphalt driveway with regular sealcoating every 2-3 years will serve you well for decades in Ottawa's challenging climate.