No single person invented asphalt. Naturally occurring bitumen, the sticky black substance that binds modern asphalt together, has been used in construction for at least 9,000 years. But the modern asphalt pavement we drive on today traces back to a Belgian-American chemist named Edward de Smedt, who patented a paving composition in 1870 and laid the first asphalt road surface in the United States.
Ancient Peoples Used Natural Bitumen for Thousands of Years
Long before anyone thought of paving roads, people in what is now northern Iraq, southwest Iran, and the Dead Sea region were collecting naturally occurring bitumen, a thick, tar-like substance that seeps from the earth. As far back as 7000 to 6000 BC, they used it to waterproof baskets, earthenware jars, storage pits, wooden posts, and rooftops. It was essentially the all-purpose sealant of the ancient world.
In Mesopotamia, bitumen became a building material on a grand scale. It served as mortar in the construction of palaces, temples, and ziggurats, including the famous “Tower of Babel” in Babylon. The legendary Hanging Gardens of Babylon used bitumen to waterproof their terraces. And in at least one case, bitumen was used as a road surface: the Processional Way of Babylon, a grand avenue leading to the city’s main gate, was coated with it. So the idea of putting bitumen on a road is genuinely ancient, even if the technique looked nothing like modern paving.
Better Roads Before Asphalt: The Macadam System
The story of modern asphalt required a revolution in road building first. In the early 1800s, Scottish engineer John Loudon McAdam developed a system that transformed road construction across Europe. Rather than digging roads into the ground, McAdam raised them above the surrounding land to promote water runoff. He dug drainage ditches on each side and layered stones of decreasing size: large stones for the base, then progressively smaller ones (none larger than four ounces) packed tightly on top. This “macadamized” road was far more durable and cheaper to maintain than anything that came before it. The layered stone surface would later become the perfect foundation for asphalt coatings.
Europe’s First Asphalt Roads
The first true asphalt pavement appeared in Paris. In June 1835, workers laid a mastic asphalt surface on the Pont Royal bridge using naturally occurring asphalt from Seyssel, France. This was a hot, pourable mixture spread over a solid base, more like a thick coating than the asphalt we know today.
A key insight came in 1849, when Swiss engineer M. Merian noticed something happening on the roads near the Val de Travers asphalt mine. Fragments of rock asphalt that fell from transport carts were being crushed and compacted by cart wheels during the summer heat, forming a crude but surprisingly smooth pavement surface. Merian realized this process could be replicated deliberately. His observation led to the construction of a compacted asphalt roadway on the Rue Bergère in Paris, using a roller to compress the material. This was a pivotal step toward the machine-compacted asphalt roads that would follow.
Edward de Smedt and the First American Asphalt
Edward Joseph de Smedt, a Belgian immigrant living in New York, filed a patent on April 5, 1870 for a new paving composition. His innovation solved a practical problem: natural asphalt from Trinidad’s famous pitch lake was soft and prone to melting in heat. De Smedt’s formula blended this soft Trinidad bitumen (40 to 80 percent of the mix) with harder, less fusible asphalts known as Ritchie mineral and Albertite (20 to 60 percent). The harder asphalts were ground to a fine powder and stirred into the melted softer asphalt. Sand, gravel, or broken stone could be added for body and structure.
That same year, de Smedt laid his composition on a street in Newark, New Jersey, creating the first asphalt pavement in the United States. Four years later, in 1874, he paved Grand Place in Washington, D.C. with a similar sheet of Trinidad-based asphalt. Then in 1876, Pennsylvania Avenue itself was resurfaced with asphalt after its previous wooden-block surface had begun to splinter and turn dangerously slippery when wet. The success of these projects triggered a wave of asphalt paving in cities across the country.
The Shift to Petroleum-Based Asphalt
De Smedt’s formula and the early European pavements all relied on naturally occurring asphalt, mined from deposits or pitch lakes. That changed quickly. By the mid-1870s, California oil producers were already making asphalt as a byproduct of petroleum refining. In 1902, a Texas oil company began supplying a similar refined product. With these cheaper, more abundant domestic sources, petroleum-based asphalt dominated the market by 1910.
This shift is why asphalt became so widespread. Instead of shipping heavy natural bitumen from Trinidad or mining it from European deposits, road builders could source it from the same refineries that were already producing kerosene and other fuels. The petroleum boom made asphalt cheap and available at industrial scale, turning it from a specialty material into the default road surface around the world.
What “Asphalt” Actually Means
The terminology can be confusing because it varies by region. In technical terms, bitumen is the black, sticky binding agent, while asphalt (sometimes called asphalt concrete) is the finished mixture of bitumen with aggregates like sand, gravel, and crushed stone. Bitumen holds the mix together; the aggregates give it strength and structure. In American English, though, “asphalt” is often used loosely to mean bitumen itself. When someone says “asphalt road,” they mean a road surfaced with that bitumen-and-aggregate mixture.
Tar, despite sounding similar, is a different substance entirely. It comes from heating coal or wood in the absence of air, while bitumen comes from petroleum. The two were sometimes used interchangeably in older road construction, but modern roads use petroleum-derived bitumen almost exclusively.