Crushed stone

Last updated
20 mm (0.79 in) crushed stone, used for construction aggregate and landscape applications 20mm-aggregate.jpg
20 mm (0.79 in) crushed stone, used for construction aggregate and landscape applications

Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from naturally occurring gravel, which is produced by natural processes of weathering and erosion and typically has a more rounded shape.

Contents

Use

Crushed limestone quarry near Bellefonte, Pennsylvania Hanson Aggregates Bellefonte PA.jpg
Crushed limestone quarry near Bellefonte, Pennsylvania

Background

Crushed stone is a major basic raw material used by construction, agriculture, and other industries. Despite the low value of its basic products, the crushed stone industry is a major contributor to and an indicator of the economic well-being of a nation. [5] The demand for crushed stone is determined mostly by the level of construction activity, and, therefore, the demand for construction materials. [6]

Stone resources of the world are very large. High-purity limestone and dolomite suitable for specialty uses are limited in many geographic areas. Crushed stone substitutes for roadbuilding include sand and gravel, and slag. Substitutes for crushed stone used as construction aggregates include sand and gravel, iron and steel slag, sintered or expanded clay or shale, and perlite or vermiculite. [7]

A crushed stone barge in China CrushedStoneBarge.jpg
A crushed stone barge in China
Crushed stone laid as a road base 2d Av subway crush stone 72 jeh.jpg
Crushed stone laid as a road base

Crushed stone is a high-volume, low-value commodity. The industry is highly competitive and is characterized by many operations serving local or regional markets. Production costs are determined mainly by the cost of labor, equipment, energy, and water, in addition to the costs of compliance with environmental and safety regulations. These costs vary depending on geographic location, the nature of the deposit, and the number and type of products produced. Crushed stone has one of the lowest average by weight values of all mineral commodities. The average unit price increased from US$1.58 per metric ton, f.o.b. plant, in 1970 to US$4.39 in 1990. However, the unit price in constant 1982 dollars fluctuated between US$3.48 and US$3.91 per metric ton for the same period. Increased productivity achieved through increased use of automation and more efficient equipment was mainly responsible for maintaining the prices at this level. [6]

Transportation is a major factor in the delivered price of crushed stone. The cost of moving crushed stone from the plant to the market often equals or exceeds the sale price of the product at the plant. Because of the high cost of transportation and the large quantities of bulk material that have to be shipped, crushed stone is usually marketed locally. The high cost of transportation is responsible for the wide dispersion of quarries, usually located near highly populated areas. However, increasing land values combined with local environmental concerns are moving crushed stone quarries farther from the end-use locations, increasing the price of delivered material. Economies of scale, which might be realized if fewer, larger operations served larger marketing areas, would probably not offset the increased transportation costs. [6]

United States statistical data

According to the United States Geological Survey, 1.72 billion tons of crushed stone worth $13.8 billion was sold or used in 2006, of which 1.44 billion tons was used as construction aggregate, 74.9 million tons used for cement manufacture, and 18.1 million tons used to make lime. Crushed marble sold or used totaled 11.8 million tons, the majority of which was ground very fine and used as calcium carbonate.

In 2006, 9.40 million tons of crushed stone (almost all limestone or dolomite) was used for soil treatment, primarily to reduce soil acidity. Soils tend to become acidic from heavy use of nitrogen-containing fertilizers, unless a soil conditioner is used. Using aglime or agricultural lime, a finely-ground limestone or dolomite, to change the soil from acidic to nearly neutral particularly benefits crops by maximizing availability of plant nutrients, and also by reducing aluminum or manganese toxicity, promoting soil microbe activity, and improving the soil structure.

In 2006, 5.29 million tons of crushed stone (mostly limestone or dolomite) was used as a flux in blast furnaces and in certain steel furnaces to react with gangue minerals (i.e. silica and silicate impurities) to produce liquid slag that floats and can be poured off from the much denser molten metal (i.e., iron). The slag cools to become a stone-like material that is commonly crushed and recycled as construction aggregate.

In addition, 4.53 million tons of crushed stone was used for fillers and extenders (including asphalt fillers or extenders), 2.71 million tons for sulfur oxide removal-mine dusting-acid water treatment, and 1.45 million tons sold or used for poultry grit or mineral food.

Crushed stone is recycled primarily as construction aggregate or concrete.

Crushed stone simulating a natural deposit at the Huntington Desert Garden, California Huntington Desert Garden, May 2009.jpg
Crushed stone simulating a natural deposit at the Huntington Desert Garden, California

See also

Related Research Articles

<span class="mw-page-title-main">Concrete</span> Composite construction material

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.

<span class="mw-page-title-main">Limestone</span> Sedimentary rocks made of calcium carbonate

Limestone is a common type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils, and these provide scientists with information on ancient environments and on the evolution of life.

<span class="mw-page-title-main">Marble</span> Non-foliated, metamorphic rock, commonly used for sculpture and as a building material

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term marble refers to metamorphosed limestone, but its use in stonemasonry more broadly encompasses unmetamorphosed limestone. Marble is commonly used for sculpture and as a building material.

<span class="mw-page-title-main">Perlite</span> Amorphous volcanic glass

Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial mineral, suitable "as ceramic flux to lower the sintering temperature", and a commercial product useful for its low density after processing.

<span class="mw-page-title-main">Iron ore</span> Ore rich in iron or the element Fe

Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite (Fe
3
O
4
, 72.4% Fe), hematite (Fe
2
O
3
, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H2O), 55% Fe) or siderite (FeCO3, 48.2% Fe).

<span class="mw-page-title-main">Gravel</span> Mix of crumbled stones: grain size range between 2 – 63 mm according to ISO 14688

Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone.

<span class="mw-page-title-main">Asphalt concrete</span> Composite material used for paving

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 asphalt, laid in layers, and compacted. The process was refined and enhanced by Belgian-American inventor Edward De Smedt.

<span class="mw-page-title-main">Macadam</span> Road building method by John Loudon McAdam

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.

Industrial resources (minerals) are geological materials which are mined for their commercial value, which are not fuel and are not sources of metals but are used in the industries based on their physical and/or chemical properties. They are used in their natural state or after beneficiation either as raw materials or as additives in a wide range of applications.

<span class="mw-page-title-main">Concrete recycling</span> Re-use of rubble from demolished concrete structures

Concrete recycling is the use of rubble from demolished concrete structures. Recycling is cheaper and more ecological than trucking rubble to a landfill. Crushed rubble can be used for road gravel, revetments, retaining walls, landscaping gravel, or raw material for new concrete. Large pieces can be used as bricks or slabs, or incorporated with new concrete into structures, a material called urbanite.

<span class="mw-page-title-main">Construction aggregate</span> Coarse to fine grain rock materials used in concrete

Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined materials in the world. Aggregates are a component of composite materials such as concrete and asphalt; the aggregate serves as reinforcement to add strength to the overall composite material. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under foundations, roads, and railroads. In other words, aggregates are used as a stable foundation or road/rail base with predictable, uniform properties, or as a low-cost extender that binds with more expensive cement or asphalt to form concrete. Although most kinds of aggregate require a form of binding agent, there are types of self-binding aggregate which do not require any form of binding agent.

Graniterock is an American corporation, founded in 1900 as "Granite Rock", and based in Watsonville, California. It operates in the construction industry providing crushed gravel, sand, concrete, asphalt and paving services.

<span class="mw-page-title-main">Gurney Slade quarry</span> Limestone quarry in Somerset, England

Gurney Slade quarry, grid reference ST626497 is a limestone quarry near Gurney Slade between Binegar and Holcombe, on the Mendip Hills, Somerset, England.

Hydrocarbons are the leading sector in Algeria's mineral industry, which includes diverse but modest production of metals and industrial minerals. In 2006, helium production in Algeria accounted for about 13% of total world output. Hydrocarbons produced in Algeria accounted for about 2.9% of total world natural gas output and about 2.2% of total world crude oil output in 2006. Algeria held about 21% of total world identified resources of helium, 2.5% of total world natural gas reserves, and about 1% of total world crude oil reserves.

In 2006, Cambodia's mineral resources remained, to a large extent, unexplored. Between 2003 and 2006, however, foreign investors from Australia, China, South Korea, Thailand, and the United States began to express their interest in Cambodia's potential for offshore oil and gas as well as such land-based metallic minerals as bauxite, copper, gold, and iron ore, and such industrial minerals as gemstones and limestone.

<span class="mw-page-title-main">Sand</span> Granular material composed of finely divided rock and mineral particles

Sand is a granular material composed of finely divided rock and mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.

In 2014, the United States was the world’s third-largest producer of raw steel, and the sixth-largest producer of pig iron. The industry produced 29 million metric tons of pig iron and 88 million tons of steel. Most iron and steel in the United States is now made from iron and steel scrap, rather than iron ore. The United States is also a major importer of iron and steel, as well as iron and steel products.

The cement industry in the United States produced 82.8 million tonnes of cement in 2015, worth US$9.8 billion, and was used to manufacture concrete worth about US$50 billion. The US was the world's third-largest producer of cement, after China and India. The US cement industry includes 99 cement mills in 34 states, plus two plants in Puerto Rico. The industry directly employed 10,000 workers in 2015. Ten percent of the cement used in the United States in 2015 was imported.

<span class="mw-page-title-main">Aggregate (geology)</span> Mass of rock, gravel, sand, soil particles, or of minerals in a rock

In the Earth sciences, aggregate has three possible meanings.

In 2017, the aggregate industry in the United States mined and sold 2.12 billion metric tons of crushed rock, sand and gravel valued at US$20.9 billion. There are thousands of aggregate-producing companies in the US, operating in each of the 50 states, and employing 105,000 people. Most aggregate is used by the construction industry, where it is an essential raw material and the main ingredient in concrete and asphalt concrete.

References

  1. Max Lay (1998). Handbook of Road Technology (Transportation Studies). Washington, DC: Taylor & Francis. p. 28. ISBN   90-5699-159-0. The strength and stiffness of the course of compacted angular stone came from the mechanical interlock which developed between individual pieces of stone. The principle is still used in modem road construction and since 1820 McAdam's name has been remembered by the term macadam used to describe the courses of unbound angular stone which he introduced.
  2. Cunningham, William D.; McKetta, John J. (1976). Encyclopedia of chemical processing and design. New York, N.Y: Marcel Dekker. p. 284. ISBN   0-8247-2605-7. Crushed stone can be used without binder for a variety of construction or industrial applications, or it may be mixed with a matrix binding material, such as bituminous or portland cement.
  3. Cornell University: Gardening Resources - mulches. accessed 5.10.2011
  4. AboutGardens: Crushed stone driveways. accessed 5.10.2011
  5. "USGS Minerals Information: Crushed Stone". U.S. Geological Survey . Retrieved 2007-11-11.
  6. 1 2 3 Tepordei, Valentin V. (1997-11-04). "Statistical Compendium - Crushed Stone". Minerals Information. U.S. Geological Survey. Retrieved 2007-11-11.
  7. Willett, Jason Christopher (January 2007). "Stone (Crushed)" (PDF). Mineral Commodity Summaries. U.S. Geological Survey. Retrieved 2007-11-11.