Transportation
Why Asphalts Are Preferable to Concrete for Road Building in Cold Climates Like Canada
Why Asphalts Are Preferable to Concrete for Road Building in Cold Climates Like Canada
When it comes to constructing roads in cold regions such as Canada, the choice between asphalt and concrete presents significant advantages for asphalt. This article explores the benefits of choosing asphalt over concrete for road construction in these challenging environments, drawing on real-world examples and technical insights.
The Unique Benefits of Asphalts in Cold Climates
In cold regions like Maine, where I live, the choice of surface material for roads is critical for safety and longevity. Asphalts, also known as bituminous surfaces, offer several advantages over Portland Cement Concrete (PCC) in these harsh conditions. One of the most notable benefits is the accelerated melting of snow and ice on asphalt surfaces due to the sun's radiation.
Superior Melting Properties of Asphalt
When the sun shines, asphalt surfaces melt snow and ice more efficiently than concrete. This is due to the lower thermal mass of asphalt compared to concrete. Asphalts have a lower specific heat capacity, meaning they absorb and lose heat energy more quickly. This rapid response to solar radiation means that asphalt surfaces warm up and cool down more quickly than concrete, leading to faster melting of snow and ice.
Enhanced Safety During Winter Months
In cold climates, the presence of snow and ice on roads presents a high risk of accidents. As asphalt melts snow and ice more quickly, the roads remain safer for drivers and pedestrians. This is especially important in regions like Canada, where extended periods of subzero temperatures are common. The improved traction and reduced risk of icy patches make asphalt the safer choice for road construction in cold regions.
Longevity and Durability
While some roads in cold regions are made entirely of PCC, studies and practical experience show that overlaying existing PCC roads with asphalt can enhance their longevity. Even when PCC roads are overlaid with asphalt, the asphalt layer tends to last longer than PCC alone. This is attributed to the ability of asphalt to absorb and distribute stress more effectively, reducing the risk of cracking and fracturing.
Practical Examples
In Canada, numerous roads and highways have been converted from PCC to asphalt, and the results have been overwhelmingly positive. For instance, the Trans-Canada Highway, a major artery through the snowy provinces, has seen significant improvements with asphalt overlays. Drivers and local authorities report fewer winter-related accidents and improved road conditions.
Technical Challenges and Solutions
While asphalt offers numerous benefits, there are also technical challenges to consider, particularly in very cold regions. Cracking, especially at the joints, can be a concern in asphalt surfaces. However, these issues can be addressed with advanced paving techniques and materials. Using high-quality bitumen and implementing properly engineered joint systems can help mitigate these problems and ensure that asphalt surfaces remain intact and safe.
Conclusion
In cold climates like Canada, the advantages of asphalt over concrete for road construction are clear. From better melting properties and enhanced safety to improved longevity, asphalt offers a superior solution. As technology and engineering continue to advance, the use of asphalt in these challenging environments is likely to become even more prevalent, ensuring safer and more reliable roads for years to come.