Domestic and worldwide demand for sustainable construction methods and energy have concrete pavement poised for a profitable new chapter. Construction
Don Marsh, Editor
Domestic and worldwide demand for sustainable construction methods and energy have concrete pavement poised for a profitable new chapter. Construction buyers’ sustainability criteria are driving life-cycle cost and embodied (cradle-to-grave) energy measurements that favor concrete over alternative materials in almost all load-bearing construction. Meanwhile, an impending shift to sustained higher oil prices is steering petroleum refiners toward processes that tax the supply of binder critical to asphalt pavement’s first-cost advantage over concrete.
Concrete pavement interests see opportunities in parking lots and mainline transportation. During the July installment (note page 6) of his ÎHard FactsÌ seminar, northern Illinois contractor Len Swederski observed, Oil and asphalt prices have provided inexpensive road surfacing and dust control for more than 200 years, adding how that era will likely end with changes in petroleum refining aimed at maximizing net gasoline and diesel per barrel of crude oil.
Swederski pointed out that in 1973, refiners were extracting only 60 percent of each $3/barrel of crude oil for fuel, leaving the remainder as asphalt tar. An abundance of bitumen, the asphalt pavement binding agent, could be economically derived from the tar byproduct. Using a ConocoPhillips breakdown of current crude oil end uses, the contractor showed that bitumen now represents a mere 1.7 percent of product derived from each barrel. Major investments refiners have made to extract more fuel from crude Û typically coker units hovering in the $1 billion range, with 1- to 3-year payback Û practically cap the amount of bitumen that will be available for asphalt.
Days before ÎHard FactsÌ, Portland Cement Association Chief Economist Ed Sullivan demonstrated how concrete enjoys an initial bid advantage of $82,000 compared to asphalt for one mile of standard two-lane roadway. Using cost estimates from state department of transportation-adopted software, his Update: Paving, The New Realities report compares current numbers against those of 2003, when asphalt held a $120,000 first-cost edge. By 2015, the report suggests, concrete roads will enjoy a $500,000 initial bid cost advantage over asphalt.
Given the supply challenges facing asphalt and the need to repair and expand the nation’s infrastructure, if all roads in 2015 were paved with concrete, state governments would save $37.5 billion in initial paving costs, Sullivan contends. During the roads’ life cycle, the savings resulting from paving with concrete compared to asphalt would total nearly $55 billion dollars.
The potential savings incurred by choosing concrete are overwhelmingly compelling, particularly at a time when states are facing tight budgets. The new realities in construction materials will force DOTs to make huge changes to how they evaluate road-paving projects.
Much of the savings stems from durability. PCA’s recent survey of DOT specifiers concludes that concrete pavement on average lasts 29.3 years before a major rehabilitation is required Û against 13.6 years for asphalt pavement. Moreover, the changes in refining practices and the potential of reduced import supplies, coinciding with increased paving material demand, may create future asphalt shortages. Those conditions stand to continue the price escalation that has plagued blacktop materials for much of this decade.
With or without timely (pre-October 2009) reauthorization of the federal highway bill, our global economy has sowed new roadway and parking lot pavement cost schedules for budget-strapped state DOTs and private developers.