Word of the Day: Macadam

Macadam paved road

Word of the Day: Macadam

noun — muh-KAD-um


: a roadway or pavement of small closely packed broken stone


The sloping, curved street saw light traffic and had a smooth macadam surface that made it popular with skateboarders.

“Littered on the beach are nearly a dozen big slabs of macadam and even larger chunks of concrete that have slid down the cliff.” — Chris Burrell, The Patriot Ledger (Quincy, Massachusetts), 20 Aug. 2016

Did You Know?

In 1783, inventor John Loudon McAdam returned to his native Scotland after amassing a fortune in New York City. He became the road trustee for his district and quickly set his inventiveness to remedying the terrible condition of local roads. After numerous experiments, he created a new road surfacing material made of bits of stone that became compressed into a solid mass as traffic passed over them. His invention revolutionized road construction and transportation, and engineers and the public alike honored him by using his name (respelled macadam) as a generic term for the material or pavement made from it. He is further immortalized in the verb macadamize, which names the process of installing macadam on a road.v

My Take

Macadam, hey, a word I not only know but I know well. In fact, I use it everyday life. Just two months ago, I had my driveway serviced with a top coat of macadam. It looks great, and it will sustain my home for decades to come. Some people call it asphalt paving, but that is not entirely accurate.

“Asphalt pavement is made up of stone (aggregate), sand, additives and liquid (petroleum) asphalt. Liquid asphalt – a black sticky substance – is used as the binding material in asphalt pavements. It is viscous in nature and also in semi-solid forms. Another common term for asphalt is bitumen. The pavement – once mixed – consists of 90 to 95% aggregate and sand, and 5 to 10% asphalt or bitumen.” (Source: http://www.pavemanpro.com/article/how_to_sealcoat_parking_lot_chapter_1)

Since macadam is only 5 to 10% bitumen, macadam is a more accurate name for the substance.

What I don’t care for are the potholes that frequently occur during the freezing / warming seasons. If macadam has even the smallest void, water can seep into the macadam. During freezing cycles, the water expands and forces the aggregate to disengage from the roadway, allowing more water to flow into the void. As the ice melts, the disengaged aggregate washes away. The result is a hole that grows into what we call potholes. Potholes are the bane of our cars, from minor tire damage to broken axles. Something that I am sure every driver knows. I’m not saying anything you don’t already know. Of that I am certain.

Brought to you by Merrian-Webster, Word of the Day.

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