Term: Asphalt concrete
**Asphalt Concrete Mixtures:**
– Hot-mix asphalt concrete (HMA) involves heating asphalt binder and aggregate.
– Warm-mix asphalt concrete (WMA) uses additives to lower mixing temperatures.
– Cold-mix asphalt concrete is made by emulsifying asphalt in water.
– Cut-back asphalt concrete is produced by dissolving asphalt binder in kerosene.
– Mastic asphalt concrete is created by heating bitumen and adding aggregate.
**Performance Characteristics of Asphalt Concrete:**
– Varying surface durability and tire wear among different types of asphalt concrete.
– Lower roadway noise compared to Portland cement concrete.
– Easier drainage due to asphalt’s viscosity.
– Concrete’s higher durability but potential need for specific drainage methods.
– Common use on high-traffic pavements due to performance advantages.
**Specialty Asphalt Mixtures:**
– Stone-matrix asphalt for a strong wearing surface.
– Porous asphalt pavements for water drainage.
– High-modulus asphalt concrete for high fatigue resistance.
– Additives like polymers and antistripping agents for improved properties.
– Specialty mixtures tailored to specific application needs.
**History, Development, and Applications:**
– Asphalt mixtures used in pavement construction since the early 20th century.
– Various terms like asphaltic concrete and bituminous mixture in engineering.
– Common applications on roads, parking lots, airports, and environmental uses.
– Development of specialty mixtures to meet specific requirements.
– Use in embankment dams and as liners for landfills and reservoirs.
**Recycling and Sustainability in Asphalt Concrete:**
– Reclaimed asphalt pavement (RAP) as the most recycled material in the U.S.
– Incorporation of roofing shingles and other recycled materials in asphalt mixes.
– Processing methods for RAP and RAS, including recycling in asphalt plants.
– Performance considerations and challenges in using recycled components.
– Exploration of new waste materials and rejuvenators for sustainable asphalt construction.
Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with bitumen (also known as asphalt), laid in layers, and compacted.
The process was refined and enhanced by Belgian-American inventor Edward De Smedt.
The terms asphalt (or asphaltic) concrete, bituminous asphalt concrete, and bituminous mixture are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation, AC, is sometimes used for asphalt concrete but can also denote asphalt content or asphalt cement, referring to the liquid asphalt portion of the composite material.