Bitumen is a sticky, black, highly viscous liquid or semi-solid form of petroleum. In the U.S., it is commonly referred to as asphalt. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient Greek ἄσφαλτος ásphaltos. The largest natural deposit of bitumen in the world, estimated to contain 10 million tons, is the Pitch Lake in southwest Trinidad.
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is being done to try to reduce the emissions or make concrete a source of carbon sequestration, and increase recycled and secondary raw materials content into the mix to achieve a circular economy. Concrete is expected to be a key material for structures resilient to climate disasters, as well as a solution to mitigate the pollution of other industries, capturing wastes such as coal fly ash or bauxite tailings and residue.
Tarmacadam is a road surfacing material made by combining crushed stone, tar, and sand, patented by Welsh inventor Edgar Purnell Hooley in 1902. It is a more durable and dust-free enhancement of simple compacted stone macadam surfaces invented by Scottish engineer John Loudon McAdam in the early 1800s.
A road surface, or pavement, is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.
Asphalt concrete 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, laid in layers, and compacted. The process was refined and enhanced by Belgian-American inventor Edward De Smedt.
Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which crushed stone is placed in shallow, convex layers and compacted thoroughly. A binding layer of stone dust may form; it may also, after rolling, be covered with a cement or bituminous binder to keep dust and stones together. The method simplified what had been considered state-of-the-art at that point.
Permeable paving surfaces are made of either a porous material that enables stormwater to flow through it or nonporous blocks spaced so that water can flow between the gaps. Permeable paving can also include a variety of surfacing techniques for roads, parking lots, and pedestrian walkways. Permeable pavement surfaces may be composed of; pervious concrete, porous asphalt, paving stones, or interlocking pavers. Unlike traditional impervious paving materials such as concrete and asphalt, permeable paving systems allow stormwater to percolate and infiltrate through the pavement and into the aggregate layers and/or soil below. In addition to reducing surface runoff, permeable paving systems can trap suspended solids, thereby filtering pollutants from stormwater.
A pothole is a depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water first weakens the underlying soil; traffic then fatigues and breaks the poorly supported asphalt surface in the affected area. Continued traffic action ejects both asphalt and the underlying soil material to create a hole in the pavement.
A binder or binding agent is any material or substance that holds or draws other materials together to form a cohesive whole mechanically, chemically, by adhesion or cohesion.
Full depth recycling or full depth reclamation (FDR) is a process that rebuilds worn out asphalt pavements by recycling the existing roadway.
Soil cement is a construction material, a mix of pulverized natural soil with small amount of portland cement and water, usually processed in a tumbler, compacted to high density. Hard, semi-rigid durable material is formed by hydration of the cement particles.
An asphalt shingle is a type of wall or roof shingle that uses asphalt for waterproofing. It is one of the most widely used roofing covers in North America because it has a relatively inexpensive up-front cost and is fairly simple to install.
Chipseal is a pavement surface treatment that combines one or more layer(s) of asphalt with one or more layer(s) of fine aggregate. In the United States, chipseals are typically used on rural roads carrying lower traffic volumes, and the process is often referred to as asphaltic surface treatment. This type of surface has a variety of other names including tar-seal or tarseal, tar and chip, sprayed seal or surface dressing.
An asphalt plant is a plant used for the manufacture of asphalt, macadam and other forms of coated roadstone, sometimes collectively known as blacktop or asphalt concrete.
Asphalt most often refers to:
Otta seal is a type of bituminous surface treatment that was developed by the Norwegian Road Research Laboratory (NRRL). Its name is based on the location in which it was created, the Otta Valley. Otta seal was developed to be used as a temporary surfacing on new roads; however, after seeing its strength, it has been used as permanent roads as well.
Concrete is produced in a variety of compositions, finishes and performance characteristics to meet a wide range of needs.
Resperion is a company based in Scottsdale, Arizona that is involved in the creation and development of a variety of products used in road construction, soil stabilization, dust control, and natural paving alternatives.
The wearing course is the upper layer in roadway, airfield, and dockyard construction. The term 'surface course' is sometimes used, however this term is slightly different as it can be used to describe very thin surface layers such as chip seal. In rigid pavements the upper layer is a portland cement concrete slab. In flexible pavements, the upper layer consists of asphalt concrete, that is a construction aggregate with a bituminous binder. The wearing course is typically placed on the binder course which is then laid on the base course, which is normally placed on the subbase, which rests on the subgrade. There are various different types of flexible pavement wearing course, suitable for different situations.
