Dr. Haifang Wen grew up in a rural area of Shandong province, in eastern China. In his youth there were not many paved highways in the Chinese countryside.
“Lots of the roads were gravel,” he told me recently. “They were muddy when it rained. I remember riding a cow on them, or going along in a wagon pulled by a donkey.”
Living in those conditions, Wen could see quite a bit of room for improvement in road materials.
“I thought, we can do better,” he said with a smile.
Thus was born Wen’s interest in asphalt, the cheapest material that can be used to pave highways. That interest propelled him through a university education, ultimately capped by earning a doctorate in engineering at North Carolina State University. Now a professor in Civil and Environmental Engineering at Washington State University, Wen uses his education to research new ways of making asphalt better and cheaper.
The asphalt used in roads has traditionally been made from aggregate – small particles of rock – and products made from crude oil. When crude oil is refined, it produces a variety of products including light fuels like gasoline, heavier plastics, and also dense asphalt.
“But the price of asphalt made from crude oil is pretty high, about $700 to $800 per ton,” Wen told me. “That really adds up. One lane of a highway, paved for one mile, costs about $1 million. Now you know where your taxes go!”
One alternative to traditional asphalt that Wen and the people in his lab are looking into is bioasphalt. Instead of using petroleum, waste cooking oil can be processed into asphalt. Restaurants can be spared having to pay to have their waste fat hauled away, and with free raw materials the asphalt made from the waste oil can be more economical.
Bioasphalt is grey, rather than black, and after sticking my nose into a little jar of it, I can testify that it smells better than asphalt made from crude oil.