AshIndustries.com.au
Title
ASH Industries - Civil construction services Brisbane, Ipswich, Gold Coast and Sunshine Coast
Description
What is Asphalt & Bitumen
Asphalt is a blend of graded aggregate, sand, filler (generally flyash) and liquid bitumen. The materials are heated and mixed with hot bitumen which binds the materials together. The hot mixed asphalt (160 - 180 degrees C) must be laid and compacted before cooling. The surface texture is smooth and uniform, (although some asphalt designs are open-graded and course textured to reduce water spray and noise on highways). The compacted layer thickness for drives and residential streets is 25 - 40mm, increasing to 50mm + for main roads and highways.
Bitumen is also used for spray seals. Liquid bitumen is sprayed onto a prepared surface. There are different types of bitumen which can be sprayed hot or cold. Most spray seals are a two coat system. After spraying the first coat, a single sized aggregate is evenly spread then rolled. A second coat of bitumen is sprayed, then covered with a smaller sized aggregate and rolled again. The result is a rough textured finish with an amount of excess (or loose) stone on the surface which can be left or swept off after a period of time. For driveways a 10mm & 5mm aggregate is used, for roads and highways a 14mm & 7mm combination and greater is used.
