What is asphalt?

What is asphalt?

There are two types of asphalt: "petroleum asphalt," which is produced by distilling crude oil, and "natural asphalt," which exists naturally.In Japan, petroleum asphalt is generally called "asphalt." At Idemitsu Kosan, our business takes advantage of the fact that asphalt is obtained through the distillation of crude oil, which is the process of manufacturing petroleum products.
Asphalt is dark brown or black in color, and is solid to semi-solid to highly viscous liquid at room temperature, but softens when heated. Asphalt, a petroleum product, is used as a binder, and asphalt mixture mixed with stone and sand is used for road paving.In Japan, asphalt mixture and asphalt pavement are also called asphalt.

History of asphalt use

Asphalt is now used in many places around us, such as road paving, but since ancient times in human history it has been used as an adhesive and waterproofing material. Natural asphalt is thought to be the residue left after the light components of naturally occurring crude oil evaporate. For example, it is known that natural asphalt was used as an adhesive in Japan during the Jomon period, and archeological sites in Aomori, Akita, and Niigata prefectures reveal arrowheads with natural asphalt attached and arrowheads repaired with asphalt. Many pottery and clay figurines have been unearthed.

Typical uses of asphalt

Approximately 80-90% of the asphalt used in Japan is used for road paving, and approximately 10% is used as waterproofing material. It is also used in a variety of other applications, including construction piles, automobile vibration damping materials, and submarine cable protection materials.

Types of asphalt

Petroleum asphalt obtained through the distillation process of crude oil includes "straight asphalt," which is mainly used for general roads, "blown asphalt," which is harder than straight asphalt and easier to use as a building material and industrial product, and hardened Blown Asphalt that is made at customer's request. There is a "high-performance asphalt" with adjusted thickness, etc. In particular, high-performance asphalt has a wide range of uses, including highways that require durability, long-life roof waterproofing materials, and recycled materials.

straight asphalt

It is mainly used for paving roads and parking lots. Road pavement is made of a mixture of stone, sand, stone powder, and straight asphalt (asphalt mixture). The word "asphalt" brings to mind roads and pavements, but in reality, most of it is stone and sand, and asphalt makes up only about 5 to 6%. This small amount of asphalt (asphalt binder) binds and fixes stones and sand, plays the role of distributing loads and blocking rainwater.

Blown Asphalt

High performance asphalt

This asphalt has improved performance by adding rubber to straight asphalt. Used on heavy traffic roads such as national roads, expressways, and airports. The pavement lifespan is more than 1.8 times that of general straight asphalt pavement, contributing to the reduction of pavement life cycle costs and the frequency of pavement construction, thereby reducing greenhouse gas emissions.
In addition, there are recycled additives used in recyclable asphalt pavement and other materials.

Landscape pavement/light color pavement

It's not just that "road = black". We provide pavements that harmonize with any landscape, from tourist spots and historic cityscapes to futuristic buildings. In addition to colored paving using pigments, locally produced natural stones and shells can also be used for paving. In addition, we have confirmed that the temperature of the pavement surface is 8 to 10 degrees lower than that of regular black pavement, making the pavement gentle for children near the road surface and babies in strollers.

pavement regeneration

Road pavements need to be updated regularly because they develop cracks and ruts due to vehicle traffic, UV rays, and rainfall. Old paving materials removed during repair work are collected and crushed as reusable Resources, separated by size, and ultimately can be reused as asphalt mixture or roadbed material. The recycling rate (in Japan) of asphalt generated from road repair work has been approximately 99% since 2012.
Old paving materials that have been removed during repair work have asphalt attached to them, and this asphalt has been oxidized and its composition has changed due to UV rays and rainwater over the years, making it hard and brittle, so it is necessary to adjust it to the original hardness of asphalt. there is. Idemitsu Kosan's recycled asphalt and recycling additives restore the properties of asphalt that has become hard and brittle, restoring it to its original quality.