Rock Doc

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 t...