What is Asphalt ?
The word asphalt is believed to come from the creek word ” asphalizen ” which means to make hard.
Generally today asphalt is used for all types of road construction for surfacing and resurfacing highways and streets.
The first asphalt used for paving streets was about 1875, this street was paved with asphalt, placed on the street in front of the court house in Newark, New Jersey, this is believed to be the first asphalt used in the United States, asphalt was used overseas before it was used in the U.S.
Later asphalt plants were invented around 1898 and the first plant was believed to be placed in Cambridge, Mass.
There were patents filed for the process of making asphalt from refining crude oil petroleum into an asphalt base oil, then mixing the oil with sized aggregate material.
Asphalt has been known by many names—-blacktop—-tarmac—-asphalt concrete—-bituminous concrete or just plain asphalt.
Asphalt today is generally made in a drum type plant, the aggregate materials and petroleum based oil are heated to a high temperature generally above 250 degrees F. this method is known as a hot mix type plant where the asphalt after mixing is generally a hot-laid type asphalt used for road surfaces.
The advantage to a hot-laid type asphalt, it is easy to work or lay down, installs as a smooth road surface. Also the asphalt mixture can be transported in dump trucks many miles from the plant to the work site.
The hot mix asphalt is made of different sizes of aggregate for different types of uses on the surface of a roadway, the base type asphalt has larger aggregates for a base layer of asphalt and the top layer of asphalt uses a smaller type of aggregate for a smoother asphalt surface when completed.
Today paving is generally all hot mix asphalt, this material is easy to lay down using a modern asphalt paver, the asphalt is rolled in place and as the asphalt cools it becomes hard like concrete.
There are many types of asphalt today and there are many different uses for the asphalt produced.