Archive for Materials Info
What are the different Types of Gravel?
Posted by: | CommentsQ-What are the different types of Gravel?
A-Multiple types of gravel have been recognized, including;
Bank gravel: gravel intermixed with sand or clay.
Bench gravel: a bed of gravel located on the side of a valley above the present stream bottom, indicating the former location of the stream bed when it was at a higher level.
Creek rock: This is generally rounded, semi-polished stones, potentially of a wide range of types, that are dredged or scooped from river beds and creek beds. It is also often used as concrete aggregate and less often as a paving surface.
Crushed Rock: Crushed Rock is mechanically broken into small pieces then sorted by filtering through different size mesh.
Crushed Stone: This is generally Limestone or dolomite that has been crushed and graded by screens to certain size classes. Hence the name “crushed stone“. It is widely used in concrete and as a surfacing for roads and driveways, “driveway gravel” sometimes with tar applied over it. Crushed stone may also be made from granite and other rocks. A special type of limestone crushed stone is dense grade aggregate, or DGA, also known as crusher run. This is a mixed grade of mostly small crushed stone in a matrix of crushed limestone powder. Crushed stone is is very commonly used for driveways. The most common sizes of crushed stone is range from 3/8 crushed stone, 5/8 crushed stone, 3/4 crushed stone, 1 1/2 crushed stone, 2 1/2 crushed stone. You may be able to find crushed stone in other sizes as well.
Fine gravel: gravel consisting of particles with a diameter of 1 to 2 mm.
Lag gravel: a surface accumulation of coarse gravel produced by the removal of finer particles.
Pay gravel: also known as “pay dirt”; a nickname for gravel with a high concentration of gold and other precious metals. The metals are recovered through gold panning.
Piedmont gravel: a coarse gravel carried down from high places by mountain streams and deposited on relatively flat ground, where the water runs more slowly.
Plateau gravel: a layer of gravel on a plateau or other region above the height at which stream-terrace gravel is usually found.
River run gravel: naturally deposited gravel found in and next to rivers and streams.
Defined by wikipedia.com
Rock Salt- Article about shortage
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Public works directors hope to make it through the winter
The central Illinois city recently paid almost $48 a ton to replenish its rock salt supply, an increase of 30 percent — or $500,000 — over last year. Even so, Barber feels fortunate.
Some towns are paying as much as $170 a ton as salt prices nationwide soar because of shipping problems and surging demand. Hoping for the best — but preparing for the worst — communities are making plans to stretch supplies by mixing salt with sand, brine or even beet juice.
“It’s a balancing act between money and quantity,” said Barber, who expects to mix the city’s salt supply with two parts of sand, effectively cutting the per-ton cost to about $23. “This year, the dollars are going to govern for us, and we’re going to try to live within the budget.”
The Illinois Department of Transportation contracted to buy 687,730 tons of salt at prices ranging from $55 to $140 a ton. Combined with the 172,000 tons left over from last winter, the department has slightly more than what it used last winter, Secretary Milton Sees said.
In New Hampshire, the state expects to pay $2 million to $3 million more than the $8 million it typically spends on salt. In North Dakota, the state transportation department, which paid about $1.6 million for 29,000 tons of road salt last year, said the price jumped from about $40 a ton in 2004 to about $67 a ton this winter.
Possible collusion?
The wildly disparate costs have raised eyebrows.
Illinois Attorney General Lisa Madigan is investigating possible collusion among suppliers, but so far has found nothing illegal, spokeswoman Robyn Ziegler said.
Dick Hanneman, president of the Salt Institute — a trade group representing U.S. and Canadian salt manufacturers — said the price increase was caused by a “perfect storm” of factors.
Record snow in parts of the U.S. last winter depleted road salt supplies, even though suppliers shipped a near-record 20.3 million tons, up from the average 16 million tons a year through the previous decade, he said.
Then, fearing a repeat of the problem, many states increased their salt orders this year, Hanneman said. Illinois, for example, asked for 34 percent more and Iowa’s request spiked by 52 percent.
Hanneman said the handful of salt suppliers in North America have been running full throttle to try to meet demand.
There are three mines each in Louisiana and Kansas, two apiece in Texas, Ohio and Ontario, Canada, and one in New York, all serving states in the Great Lakes and Mississippi River regions, he said. Most of the salt for the East Coast comes from overseas.
Weather hasn’t always cooperated, either.
Summer flooding closed locks and dams on the Upper Mississippi River for weeks, disrupting barge shipments of road salt. Soaring U.S. gasoline prices over the summer added to the cost of transporting the salt.
Little choice
And in September, Hurricane Ike lashed the Bahamas, idling a Morton Salt site for a week. The storm also shut down production for days at the Louisiana mines.
Now, states have little choice but to pay higher prices and to try to stretch supplies.
Indiana state highway crews will use a new software program to calculate how much road salt is needed on a particular stretch of road.
In Peoria, Barber is hoping his planning pays off.
“It’s not like we’re the only ones in the boat doing this,” he said.
What are the Types of Aggregate materials used in construction?
Posted by: | CommentsQ- What are the types of Aggregate materials used in the building and construction Industry?
A-Construction aggregate, or simply “aggregate”, is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone , slag, and recycled concrete . Aggregates are a component of composite materials such as concrete and asphalt concrete; the aggregate serves as reinforcement to add strength to the overall composite material. Aggregates are also used as base material under foundations, roads, and railroads.The American Society for Testing and Materials publishes an exhaustive listing of specifications for various construction aggregate products, which, by their individual design, are suitable for specific construction purposes. These products include specific types of coarse and fine aggregate designed for such uses as additives to asphalt and concrete mixes, as well as other construction uses. State transportation departments further refine aggregate material specifications in order to tailor aggregate use to the needs and available supply in their particular locations. Sources for these basic materials can be grouped into three main areas:
Mining of mineral aggregate deposits, including sand, gravel and stone;
Use of waste slag from the manufacture of iron and steel;
Recycling of concrete , which is itself chiefly manufactured from mineral aggregates.
In addition, there are some (minor) materials that are used as specialty lightweight aggregates: clay, pumice, perlite, and vermiculite.
Defined by Wikipedia.com
What are the types of Sand used in construction?
Posted by: | CommentsQ-What are the different types of Sand?
A-Sand is a granular material made up of fine mineral particles. It is a naturally occurring, finely divided rock. Sand comprises particles, or granules, ranging in diameter from 0.0625 (or 1⁄16 mm) to 2 millimeters. An individual particle in this range size is termed a sand grain. The next smaller size class in geology is silt: particles smaller than 0.0625 mm down to 0.004 mm in diameter. The next larger size class above sand is gravel, with particles ranging from 2 mm up to 64 mm (see particle size for standards in use). Sand feels gritty when rubbed between the fingers (silt, by comparison, feels like flour).
Sand is commonly divided into five sub-categories based on size;
- very fine sand (1/16 - 1/8 mm diameter)
- fine sand (1/8 mm - 1/4 mm)
- medium sand (1/4 mm - 1/2 mm)
- coarse sand (1/2 mm - 1 mm)
- very coarse sand (1 mm - 2 mm)
These sizes are based on the Φ sediment size scale, where size in Φ = -log base 2 of size in mm. On this scale, for sand the value of Φ varies from -1 to +4, with the divisions between sub-categories at whole numbers.
Uses of sand:
- Concrete Sand is often a principal component of concrete.
- Molding Sand, also known as foundry sand, is moistened or oiled and then shaped into molds for sand casting. This type of sand must be able to withstand high temperatures and pressure, allow gases to escape, have a uniform, small grain size and be non-reactive with metals.
- Sand It is the principal component in glass manufacturing.
- Graded sand is used as an abrasive in sandblasting and is also used in media filters for filtering water.
- Brick manufacturing sand plants use sand as an additive with a mixture of clay and other materials for manufacturing bricks.
- Sand is sometimes mixed with paint to create a textured finish for walls and ceilings or a non-slip floor surface.
- Sandy soils are ideal for certain crops such as watermelons, peaches, and peanuts and are often preferred for intensive dairy farming because of their excellent drainage characteristics.
- Sand is used in landscaping; it is added to make small hills and slopes (for example, golf course sand).
- Beach nourishment - transportation to popular beaches where seasonal tides or artificial changes to the shoreline cause the original sand to flow out to sea.
- Sandbags are used for protection against floods and gun fire. They can be easily transported when empty, then filled with local sand.
- Railroads use sand to improve the traction of wheels on the rails.
Defined by wikipedia
Try our Sand Calculator to estimate how many cubic yards of sand you need for your coverage area
Crushed Stone-Statistical Compendium by U.S. Geological Survey
Posted by: | CommentsBelow is a statistacl report about crushed stone.
CRUSHED STONE
Statistical Compendium by U.S. Geological Survey, Minerals Information
Commodity Specialist: Valentin V. Tepordei (vteporde@usgs.gov) Last modification: 11/04/97
Stone, in its multitude of forms, represents a very significant part of the Earth’s crust and one of the most accessible natural resources. Stone has been used since the earliest days of our civilization, first as a tool or weapon, then as construction material, and later, in its crushed form, as one of the basic raw materials for a wide variety of uses ranging from agriculture and chemicals to complex industrial processes. At the beginning of the 20th century, the U.S. production of crushed stone was relatively small, and its uses limited. Today, crushed stone is being produced in 48 of the 50 States, and its annual production tonnage ranks first in the nonfuel minerals industry. The United States is, in general, self-sufficient in crushed stone, producing enough to meet most of the domestic needs. Small quantities of crushed stone, used mainly as construction aggregates, are being imported mostly by water from the Bahamas, Canada, and Mexico to compensate for local shortages that exist in some areas of the country.
The demand for crushed stone is determined mostly by the level of construction activity, and, therefore, the demand for construction materials. U.S. production of crushed stone recorded a significant growth in the past 40 years, from 229 million metric tons in 1950 to 1.1 billion metric tons in 1990. The highest level of production was reached in 1988–1.13 billion metric tons. Between 1950 and 1973, because of the construction of the Interstate Highway System, the growth from year to year in the production of crushed stone was almost continuous, paralleling the increased demand for construction aggregates. Following the reduction in the volume of work in the Interstate Highway Program in the late 1960’s, the crushed stone industry, while still growing, became more sensitive to the ups and downs of the economy. The 1974-75 and 1982 recessions are well reflected by low levels of production of crushed stone in those years. Future demand for crushed stone will continue to be dependent mostly on the growth of construction activity.
Most crushed stone is used for construction purposes, mainly as aggregate with or without a binder. Road base or road surfacing material, macadam, riprap, and railroad ballast are the major uses without a binder. Aggregate for cement and bituminous concrete in highway and road construction and repair and in residential and nonresidential construction are the major uses for aggregates with a binder. Other uses include cement and lime manufacture, agriculture, metallurgical flux, and fillers and extenders.
Crushed stone is a high-volume, low-value commodity. The industry is highly competitive and is characterized by thousands of 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. Despite having one of the lowest average-per- ton values of all mineral commodities, the constant dollar price of crushed stone has changed relatively little during the past 20 years. As a result of rising costs of labor, energy, and mining and processing equipment, the average unit price of crushed stone increased from $1.58 per metric ton, f.o.b. plant, in 1970 to $4.39 in 1990. However, the unit price in constant 1982 dollars fluctuated between $3.48 and $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.
Underground operations are becoming more common, especially for limestone mining in the central and eastern parts of the United States, as the advantages of such operations are increasingly recognized by the producers. By operating underground, a variety of problems usually connected with surface mining such as environmental impacts and community acceptance are significantly reduced.
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 crushed stone quarries around the country, 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.
Although crushed stone resources are widespread and in adequate supply nationally, local shortages exist. Land use conflicts and environmental problems associated with rapid urban expansion are major factors contributing to these shortages. The local shortages that occasionally exist are caused less by a lack of stone than by urban encroachment or zoning regulations that force closure of operating quarries or prevent the development of new ones. Demand pressures, land use regulations, and the cost of meeting environmental and reclamation requirements are factors that will cause a rising price trend.
Sand and gravel and to a lesser extent iron-blast-furnace slag are the predominant substitutes for crushed stone used as construction aggregate. Steel slag is another substitute for crushed stone in road bases and asphaltic concrete, but not in cement concretes because of chemical interaction. Blast-furnace slag is also used as a stone substitute in cement manufacturing.
Crushed Stone remains an abundant material, and, despite environmental, zoning, and regulatory restrictions, no shortages on a large scale are expected to occur in the future.
