manufactured sand and crushed stones processing technology for concrete | quarrying & aggregates
Aggregate is the most exploited material in the world. It is an important component of concrete and asphalt concrete, accounting for 70% of the volume of concrete. It can inhibit the shrinkage and cracking of concrete and enhance the strength of concrete.
Aggregates are divided into natural aggregates and artificial aggregates. According to the degree of thickness, they are divided into coarse aggregate (crushed stone or gravel) and fine aggregate (sand).
Due to the non-renewable resources, the mining of natural aggregates is increasingly restricted. Now, in many countries and regions, the amount of artificial aggregate has exceeded the amount of natural aggregate, and it is widely used in various concrete industries.
Rock particles (excluding soft and weathered rock particles) processed by natural rock, river pebble stone or mine waste rock through mechanical crushing, shaping, screening, powder control and other processes, including:
The wet processing technology refers to washing with water during the screening and crushing of materials, and washing the coarse and fine aggregates with the stone washing machine and sand washing machine. Generally used for raw materials containing mud or more weak particles. When the finished sand and crushed stone powder content is too high, wet production can also be used to remove part of the stone powder.
According to the nature of the soil contained in the raw materials, the sand and stone washing methods can be divided into screen surface washing and sand washing machine washing. Which stone washing method to use can be determined according to factors such as the mud content of the raw materials, the nature of the soil, and the processing volume.
High water consumption, high cost of machine-made sand and crushed stone powder recovery and sewage treatment, serious loss of fine sand and crushed stone powder, and difficulty in dehydration of finished sand; when vertical shaft impact crushing machine-made sand is used, the sand formation rate is low.The wet production process is suitable for applications in areas with abundant water resources.
Generally, it means that the pre-screening is produced by wet method and the moisture content of the discharged material is controlled, and the sand making and screening system of shaping adopts the dry production process.
After the sand-making raw materials are washed with water, they must be dehydrated mechanically or naturally to ensure that the moisture content of the raw materials entering the sand-making machine is not more than 3%, otherwise the sand-forming rate and screening efficiency of the sand-making machine will be low.
No water or very little water consumption, less stone powder loss, dry processing technology is mainly used for raw material cleaning, high sand rate, low stone powder content machine-made sand and stone system.
(1) Due to the high moisture content of the dry processing raw materials or the high soil content of the raw materials, the fine aggregate is not easy to sieve through, and the soil content or fine powder content exceeds the requirements of relevant standards.
The 40 mm clean aggregate produced by multiple crushing and screening enters the sand making system. Sand making equipment generally uses a vertical shaft impact crusher. The principle of sand making is that some or all of the raw materials enter the high-speed rotating impeller and quickly rotate, and shoot out at high speed from the evenly distributed launch ports around the impeller. The flow or the raw materials piled in the cavity are broken by repeated high-speed collisions.
After screening and fine powder separation system sorting, qualified machine-made sand and gravel are processed. Fine powder separation is divided into two types according to different processing techniques:
Wet sand washing generally adopts a flat layout. The screened artificial sand flows into the sand washing machine for sand washing, and the washed fine powder and soil enter the integrated fine sand recovery and dehydration system for fine sand recovery.
The separated mud and stone powder enter the high-efficiency thickener for concentration and dehydration, and the concentrated and precipitated mud powder is pressed into a mud cake through a filter press.
The operating cost and floor space of a complete set of wet-process artificial sand making and sewage treatment equipment are about twice that of the dry process. Due to the high cost of equipment investment and land occupation rent, sewage treatment and dewatering waste residue discharge are also very expensive, so dry sand making has been rapidly developed.
The dry sand making fine powder separation system can be set up before or after screening. The plastic sand making machine and the screening fine powder separation system are connected to the large dust collector through a pipeline. The excess fine powder in the screened sand is collected by the dust collector and stored in the fine powder tank, which is regularly transported by the tanker for later application.
Dry sand making can be arranged in a flat layout or a three-dimensional layout in a tower. Since the tower-style complete set of equipment occupies only one-fifth of that of the traditional wet method and one-third of the traditional dry method Therefore, the tower-type machine-made artificial sand system is very suitable for building with concrete mixing plants or dry-mixed mortar mixing plants, reducing the transportation cost of finished artificial sand and crushed stone aggregates and storage facilities.
corliss resources: aggregate, sand, and gravel products
3/4 Clean Crushed rock has a variety of uses. It can be used as a decorative rock. It also works well on walkways and has great drainage characteristics. 3/4 Clean Crushed rock is not the best rock for use in gravel driveways.
Streambed Gravel, Cobble, and Boulders: Rounded river rock products are offered in a range of sizes such as 2x4 Cobble, 2x8 Cobble, and Boulders ranging from 8 up to 36+. These are excellent choices for landscaping dry river beds and stream restoration projects. Contact us for available sizes.
This rock is excellent for spreading into muddy bogs on roads and driveways. Good for roadways into and out of job site; as the truck leaves the job sites the rock will scrape clean the tire treads so that less mud will be tracked onto the road.
This rock can be used for building small flower bed walls. Also used for industrial roadways. Like 2 to 4 rock, good for roadways into and out of job site. Is also great for erosion control on slopes and drainage outfalls.
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different types & sizes of aggregate for concrete engineering basic
Aggregates are one of the most important constituents of the concrete which give body to the concrete and also reduce shrinkage. Aggregates occupy 60 to 80 % of total volume of concrete. So, we can say that one should know definitely about the aggregates in depth to study more about concrete.
Fine Aggregates are usually sand or crushed stone that are less than 9.55mm in diameter.When the aggregate is sieved through 4.75mm sieve, the aggregate passed through it. Natural sand is generally used as fine aggregate, silt, stone dust and clay also come under this category. The purpose of the fine aggregate is to fill the voids in the coarse aggregate and to act as a workability agent.
Coarseaggregates are particulates that are greater than 9.5mm. The usual range employed is between 9.5mm and 37.5mm in diameter.Typically the most common size of aggregate used in construction is 20mm. A larger size, 40mm, is more common in mass concrete. Larger aggregate diameters reduce the quantity of cement and water needed because of its lower Voids.
When the aggregate is sieved through 4.75mm sieve, the aggregate retained is called coarse aggregate. Gravel, cobble and boulders come under this category. The maximum size aggregate used may be dependent upon some conditions. In general, 40mm size aggregate used for normal strengths and 20mm size is used for high strength concrete.
Gravel or Graded stone, is another coarse aggregate suitable for concrete mixes.Gravel is formed of rocks that are unconnected to each other. Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments.
Sand is the finest aggregate. It comes in different gradations: sharp sand, builders sand, and kiln-dried silver sand, which vary from coarsest to finest, respectively. Finer sands are a good aggregate for mortars and grouts. Coarser sands are also a popular aggregate for concrete mixes.
Recycled concrete as aggregate will typically have higher absorption and lower specific gravity than natural aggregate and will produce concrete with slightly higher drying shrinkage and creep. These differences become greater with increasing amounts of recycled fine aggregates.
Vermiculite Concrete Aggregate is used to create a lightweight and insulating concrete that can be used on various forms of bases suitable to a variety of engineering designs. This concrete aggregate is often used for roof deck systems and works with most concrete, wood, and metal structural decks.
Glass aggregate can replace part or all of the sand and gravel in concrete, for effects that range from colorful terrazzo, to granite- or marble-like finishes, to concrete that reflects light like a mirror. Glass aggregate can even be used to produce concrete that literally glows.
The use of slag aggregates from iron and steel production in construction dates back to the Romans who used crushed slag from the crude iron production of that time to build their roads. Nowadays, slag is still used to build roads.
products corpus christi sand & gravel
An aggregate sand usually composed of either limestone or granite. This specific type of sand has been crushed at the quarry and then washed and screened for quality. This process will make sure that there are no large rocks within the material.
It is most commonly used as a key ingredient in cement or hot asphalt but can also be used as pipe sand or as a base layer and leveling medium for above ground pools, and patios or walkways made of concrete paving stones.
Created in the same way as concrete sand but is crushed finer. It is also created at the quarry by crushing granite, gneiss, limestone or trap rock then washing it though screens to ensure the uniformity of the grains.
A mixture of various types of sand with small amounts of cement and a minimum of water is added. Because of its many uses, stabilized sand is used a great deal in the construction industry, both for small and large projects, new-builds and renovations.
Typically made up of sand and a varying amount of silt and clay. More often, the sand particles are more solid and larger than all the other particles included in the mixture, allowing more room for water and air to freely move through it. The clay and sediment in the mixture provide structure and make it more fertile.
An excavated and unscreened mixture of non-expansive clay and sand that is most commonly used during the initial phases of construction. Similar to standard fill, select fill can fill in low-lying areas and raise the elevation of any structure, building or landscaping project. It can also be used as a base under concrete foundations and paving projects.