The public, industry, and governments have become increasingly interested
in green design and sustainable development. Construction activities
affect the environment significantly, so environmental issues should
be considered seriously. Thousands of miles of roads are paved every year
with asphalt and steel-reinforced concrete. What are the environmental
effects of the two materials? If asphalt has been used overwhelmingly
over concrete, is it a better choice for sustainable development? We
present results of a life cycle inventory analysis of the two materials
based on publicly available data. We find that for the initial construction
of equivalent pavement designs, asphalt appears to have higher
energy input, lower ore and fertilizer input requirements, and lower toxic
emissions, but it has higher associated hazardous waste generation and
management than steel-reinforced concrete. When accounting for the
uncertainty in the data and when annualizing environmental effects based
on assumed average service lives of the two pavement types, the resource
input requirements and the environmental outputs are roughly comparable
for the two materials. However, asphalt pavements have been recycled
in larger quantities than concrete pavements, with consequent
resource savings and avoided pollution, which suggests that asphalt may
be a better choice from a sustainable development viewpoint. Of course,
special functional requirements or economics may dictate the use of one
material over the other in particular applications regardless of the overall
environmental effects.