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Segregation of asphalt pavements

Asphalt mixes are segregated as a result of the separation of coarse and fine aggregate particles. Mix segregation may occur in several places during the mix production, hauling, and placing operations. Segregation can occur while the mix is being delivered from the asphalt batch plant to the surge silo. This may occur when the mix is deposited into the haul truck from the silo at the asphalt batch plant. This can also happen when the truck discharges the mix into the paver hopper. Segregation can appear in both hot mix and warm mix asphalt. There are three types of segregation in asphalt depending on the location at which they appear.

· Random segregation pockets

· Side-to-side or longitudinal area along with the paver

· Dispatch point of a truckload mix.

Each type of segregation stems from a different type of issue. However, each type of segregation differs in how it affects the long-term durability of the asphalt pavement structure.

What does asphalt segregation look like?

Surfaces of pavement that are segregated have a rougher texture than their surrounding areas. Furthermore, the density of the hot mix asphalt in segregated areas is much lower than the density in nonsegregated areas.

Under traffic, ravelling f the pavement typically occurs in segregated areas. The revelled areas may increase both in size and depth as more time passes and more traffic is loaded on the road, resulting in potholes in the pavement surface. It is possible for ravelling to progress through the pavement layer completely with more time and traffic.

What can be done at the asphalt plant to limit it?

Loading the truck correctly is essential to fully eliminate truckload segregation at the asphalt batch plant. A normal triaxle or tandem truck would have to load three drops of the asphalt mix instead of one large drop. The first drop occurs as far forward as reasonably possible near the front bulkhead of the truck bed. As a result of this process, the coarse aggregate particles cannot travel much to the front of the truck bed, reducing the amount of segregation during the loading process.

A truck driver must then drive the truck forward to load the second drop in the truck bed next to the tailgate. Through this process, the particles of coarse aggregate can travel a shorter distance to the tailgate. Afterwards, the truck driver will need to move the truck backwards so that the third drop of the mix can be placed between the first and second drops of mix in the truck bed.

What can be done at the road site to limit it?

A mass of mix flows from the bed of the truck into the paver hopper when the tailgate is opened. In the truck bed, the mix continues to move in a mass as the truck bed is raised. When the truck bed is loaded correctly, the largest aggregate particles in the mix won't separate from the rest of it.

Preventing segregation at the paver

It is recommended that the paver hopper remains half full between truckloads. When the haul truck bed of the asphalt paver is empty, the amount of mix in the paver hopper should be above the bottom of the flow gates or the opening for the slat conveyors.

The segregated mix on the tailgate of the haul truck will likely mix with the asphalt mix already in the paver if it is half full. With more mix in the hopper, there is a greater chance of losing a majority of the segregated material within the mix.

#asphalt pavements

Parts of a concrete batching plant

Batching plants produce concrete for large or medium-sized construction projects, road and bridge projects, and precast concrete plants, among others. The concrete batching plant is made up of five major components, including the :

· Concrete mixer

· Weighing system

· Material delivery mechanism

· Material storage

· Control room

Concrete mixer

According to its mixing method, mixers at any concrete batching plant are classified into forced mixers and self-falling mixers. The forced mixer can mix concrete of various fluidities, semi-dry hardness, dry hardness, etc. The self-falling mixer is mostly used for stirring fluid concrete. Depending on the type of structure, forced mixers are divided into spindle planetary mixers, single horizontal shaft mixers, and twin shaft mixers. Twin-shaft mixers provide the most efficient performance.

Weighing system

Among the key factors affecting concrete quality and production cost is the material weighing system. Weighing is divided into three parts: aggregate weighing, cement weighing, and water weighing.

Material delivery mechanism

The material delivery system at any concrete batching plant consists of three parts.

Aggregate delivery

Aggregate delivery can take any of the two forms: hopper system or belt conveyor. Simple structure and small footprint are the advantages of hopper transportation. Transport by the belt is advantageous because it can cover a large area, is highly efficient, and has a low fault rate

Powder delivery

Concrete is mainly composed of cement, fly ash, and mineral powder. Screw conveyor currently is the most widely used powder conveying mode. A pneumatic conveyor and scraper conveyor transport is usually used in the large concrete mixing plant.

Liquid delivery

Transportation of water and liquid admixtures is usually made with water pumps. For concrete cooling purposes, flake ice plants are also used sometimes to replace water completely or partially.

Material storage

For concrete, the storage of materials is essentially the same. A large commercial concrete mixing station has a closed silo for large amounts of aggregates stacked outside. Stacks of powder are stored in an enclosed steel silo. Admixtures are held in steel containers. There are also storage silos for the prepared concrete, where it is held for short periods before transporting it to the trucks.

Control room

The control room is the brain of the concrete batching plant system. Depending on the user's requirements and the size of the mixing station, the control system offers different functions as the complexity of concrete plants differs from plant to plant.

The working mechanism of a concrete batching plant

Concrete batching begins with the aggregates being fed into the individual bins. Using the control panel, the aggregates are weighed individually according to the mix design. As soon as the aggregates have been weighed, they are transferred into the mixing unit. Over the mixing unit, there are weight hoppers that are used to transfer the cement, additives, and water. Through the use of weighing conveyors, cement is transferred and water is pumped. Concrete is mixed in a twin-shaft mixer, where all the ingredients are uniformly mixed. There could be other types of mixers as listed above. With the aid of the control panel, a timer is set for mixing the ingredients. Once the timer expires, the mixing process stops, and the concrete is then loaded into the truck for transportation to the construction site.

#concrete batching plant

Importance of baghouse in Asphalt mixing plants

Asphalt plants combine gravel, sand, and crude oil derivatives to make the tar used for roads, highways, and parking lots across the world. During production, these plants release millions of pounds of chemical compounds into the air. By using anti-pollution equipment, dust emissions in asphalt plants can be controlled. A multi-cyclone dry dust collector, a venture-type wet dust collector, and a baghouse are some types of dust collectors commonly used for capturing dust in asphalt mixing plants. In most cases, two or more of these pollution control devices are used in succession.

What are baghouses?

Baghouses are large-scale pollution control devices with enclosures that contains “bags”, which act as filters to remove pollutants. The filter effectively removes dust, ash, soot, and other particles from the exhaust.

It's the plant operator's responsibility to ensure that dust limits are not exceeded at the plant to comply with environmental standards, by maintaining a functioning baghouse.

What do they do?

A baghouse is located above a hopper, which is a funnel-shaped container. As dust-laden exhaust passes through the hopper, it passes through long, cylindrical bags made of either woven fabric or felt. By allowing air to pass through, but capturing particles and pollutants, the bag serves as an extremely effective filter. In baghouses, the following four collection mechanisms are typically used to accomplish filtration:

Inertial collection

Dust particles are struck by bag fibres perpendicular to the air dust flow during inertial collection. Instead of allowing them to change direction with the air stream, they are trapped by inertia.

Interception

During interception, the dust particles are captured by the fibres of the bag due to the fibre’s size.

Brownian movement

During Brownian Movement, very tiny particles of submicrometer size are diffused. This diffusion increases the likelihood of particles and fibre surfaces contacting each other.

Electrostatic charge

Particle filtration is also assisted by electrostatic forces. The electrostatic charge between particles and fibres in the bag increases dust capture.

It should be maintained

Maintaining the baghouse at your asphalt mixing plant is important.

Following items should be checked for routine maintenance of baghouses:

· Inspect all solenoids for proper operation and replace if necessary.

· Calculate pressure, pulse duration, and interval. Keep an eye on the level of pressure in each bag.

· Ensure the bags in the manifold are pulsating at an appropriate pressure by monitoring the pressure in the manifold.

· Visually inspect the bags monthly.

· In order for pulse air to enter the bag, the blowpipes should be properly aligned. Walking on blowpipes can warp and misalign them.

· The venturis, which cause the shockwave to travel through the bag, need to be in good working order.

· The exhaust system should be checked for leaks, such as aggregate and recycle inlets, connection bands on ductwork, holes in equipment, and access doors that aren't tightened or missing/damaged seals.

To sum up, A baghouse must not only maintain a high level of airflow to support the production process at the asphalt mixing plant, but it must also maintain an extremely high collection efficiency if it is to function effectively.

#Asphalt mixing plants

How to prevent cracks in concrete

There are many reasons why concrete can crack. Concrete, like most other building materials, moves with changes in moisture content, so cracking in concrete construction is inevitable unless appropriate measures are taken to prevent it. Concrete shrinks as moisture evaporates. In this article, we will discuss why concrete cracks, what are the type of concrete cracks and how we can prevent them at the batching plant or at the construction site.

Why it cracks

Excess water

The maximum strength of concrete can be achieved with little water. Nevertheless, a large number of residential concrete projects add too much water to the concrete on the job site. Concrete is made easier to install with the added water. Unfortunately, it also weakens the concrete. Cracking is caused by the shrinkage. When concrete dries and hardens, it shrink as the excess water in the mix evaporates.

Quick-drying

A slab that is rapidly dried will be significantly more likely to crack. Concrete becomes solid through a chemical reaction that requires water. After you pour the concrete, this chemical reaction continues for days and weeks. Curing the slab adequately will ensure that the necessary water is available for this reaction.

Not up to the desired strength

There are many different strengths of concrete. Make sure the concrete you're pouring has the correct strength.

Absence of joint

Concrete cracking can be controlled with control joints. There should be no more than 2-3 times (in feet) of the thickness of the concrete (in inches) between joints. Therefore, 4" concrete joints should be 8-12' apart.

Concrete crack types

Some cracks are more serious than others. Some of the crack types are.

· A hairline crack at the surface should be repaired if it is widening with time, is a hazard, collects dirt, or is unsightly.

· Proper joint placement can reduce or prevent shrinkage cracks that can occur during the curing process of concrete.

· The ground beneath a slab sinks when it hasn't been compacted properly, causing settlement cracks.

· Repair or replacement of the concrete is necessary when structural cracks are wider than a quarter of an inch or run through the entire slab.

How you can prevent it

· In the first few days after the pour, there are several things you can do to ensure that the concrete will be strong and crack-free. For concrete to reach its full strength, cement (the binding ingredient) must retain moisture. If the moisture evaporates slowly, the concrete is less likely to crack. Concrete cooling techniques can be adopted here especially for hot climates where moisture evaporates much quickly. A flake ice plant with your ready mix concrete batching plant can be helpful.

· Control joints play a crucial role. Almost a quarter of the slab's depth is cut out to anticipate and direct future cracks. There is a high probability that cracks will occur in these weak spots.

· You should be sure of the strength of concrete you are using. Normally samples of concrete coming out from the concrete batching plant are taken for testing. The concrete should meet the desired strength levels. If strength is low, you may have to alter your mix design. Alternatively, concrete can be strengthened with polypropylene fibers.

#concrete batching plant #cracks in concrete

Failures in asphalt pavements

When asphalt surfaces fail, they no longer hold their original shape and develop material stress, which leads to problems. Pavement failure can be attributed to several factors including water intrusion, heavy vehicle stress, seasonal temperature changes, and sun exposure. Failures in asphalt pavements can be avoided by following good practices starting with the asphalt plants. Therefore, asphalt plants are critical to the quality and efficiency of asphalt pavement construction.

Some of the types of pavement failure include:

· Cracking due to extreme load or segregation. leading to the development of potholes.

· Depression and rutting

· Upheavals and ravelling.

Cracking and potholes

Due to its tendency to spread and the variety of factors contributing to cracking, asphalt cracking accounts for the majority of pavement failures. Potholes are formed when water penetrates into cracks in the surface for a long time. Asphalt stress cracks, such as alligator cracks, will erode the surface all the way down to the subbase if not treated. Large holes will form in the asphalt as a result of this, and vehicles will have to bear the damage.

Depression and rutting

Uneven sub-bases and long-term compactions cause depressions in an asphalt surface. Depressions have a lower elevation than the asphalt pavement, so they can hold water for a longer period of time. Over time, rutting develops on an asphalt surface because of weight limits exceeding and improper base construction. When heavy vehicles travel along a roadway, they compact the asphalt, causing tire ruts. When rutting occurs on an asphalt surface, the base needs to be repaired or restructured to accommodate heavier traffic.

Raveling

Raveling is caused by the continuous intrusion of water and the degradation of asphalt topcoats. Water and sunlight continue to damage the asphalt surface once the top layer of asphalt bitumen wears away, causing the bond between the asphalt and aggregate to weaken. An asphalt surface that has ravelled loses its impervious properties, allowing water to penetrate. A crack will occur on an asphalt surface caused by water intruding into the surface.

How operations at asphalt plants can cause failure in asphalt pavements

Temperature miscalculations

Asphalt production is subject to strict temperature requirements. The asphalt scorching at too high temperatures and the gravel mixing unevenly at too low temperatures can cause a reduction in the strength of asphalt, which will lead to pavement failure.

The reasons for temperature miscalculations are two-fold: the temperature control of asphalt heating is inefficient, and the temperature control of sand and gravel heating is inefficient. Modern asphalt drum mix plants and batch mix plants have built-in automation to limit temperature miscalculations.

The ratio of asphalt to gravel is unstable

Asphalt quality is primarily influenced by the weight ratio of asphalt to aggregates such as gravel and sand. Weight ratio can be disturbed if, sand and stone have a high content of dust and dirt and there is an error in the measurement system. Usually, the asphalt measurement scale and the mineral powder measurement scale drift from their zero points.

Pollution caused by heavy dust

It can be caused by two major factors: the presence of a large amount of mud and dust in sand and stone materials and a dust removal system having low pulse pressure and damaged or clogged bags. The use of good-quality screening systems at asphalt plants can eliminate this problem.

#asphalt plants #asphalt pavements

Considerations When Choosing a Concrete Batching Plant

The selection of a concrete batching plant is the most important element of a successful construction project. A concrete plant investment requires pondering several aspects, weighing pros and cons, studying financial matters, and so on.

What is the best way to decide whether or not to buy a concrete plant? Here are some factors to consider before buying a concrete mixing plant.

How much can you afford?

Decide whether to lease or buy a concrete batching plant based on your budget. A concrete batching plant may be necessary for ongoing construction projects, but a batching plant can be leased for one-time construction projects. You should do the cost analysis involving logistics, installation, and taxes.

Plant capabilities

The quality of concrete produced and the reliability of the equipment go hand in hand. To achieve high-quality concrete for your construction project, you must ensure that the batch plant is reliable. Check out the various features of the batching plant and see if it has the features you are looking for. You should also pay attention to its control system as it is the real brain behind batching plant performance. The batching plant should be customisable to meet future demands and compatible with the upgrades.

You should consider an automatic or semi-automatic concrete mixing plant if your company or project is large. They facilitate the mixing of concrete and ensure its quality at the same time.

Be on the lookout for aggregate options

Buying a concrete batching plant should take this aspect into account. Therefore, you need to know the type of cement available in your area. This will determine how many aggregate bins are needed for the plant. Similarly, if you are using any special type of aggregate, the batching plant you are buying should have the capability to process it.

The brand name

Choosing a reputable and reliable manufacturer is crucial. It gives you confidence in their product and technology. Worthy manufacturers would have their products made of quality materials offer after-sale support. In addition to training on the safe and efficient operation of the concrete plant, regular maintenance and upkeep are provided.

Design options for mixes

When projects are completed, a batching plant needs to be moved from one location to another. Also, on different job sites, different mix designs must be followed, depending on the concrete strength requirements, the local aggregate quality, etc. The batching plant should be able to adapt easily to these changes. A mobile batching plant is best when you have to shift frequently from site to site.

Spares are available easily

These days, sales and service go hand-in-hand. Whenever replacements are needed, spare parts should be easily available. Repairs and service should also be timely. It is important to review the company's past performance in serving its customers

Environmental impact

The batching plant should conform to all local and international environmental standards. It should also produce minimal noise and have a good waste management plant too.

The bottom line

If you wish to purchase concrete plants, you need to consider the combination of quality and price, i.e., the equipment should be of superior quality at an affordable price.

#Concrete Batching Plant

Bleeding of concrete

Concrete consists of cement, fine aggregates, and coarse aggregates mixed in a concrete batching plant. Concrete can suffer from a number of problems due to improper mixing at the batching plant, curing, and placement at the jobsite, one of them being "bleeding". Bleeding in concrete is a segregation phenomenon that is the result of free water rising to the surface and forming a cement paste known as laitance on the surface.

What causes the bleeding?

Bleeding occurs when the aggregate particles cannot absorb the excess moisture due to a high water saturation level. Water floats up to the surface of newly poured concrete instead of soaking into the rocks and sand because it is the least dense of all the ingredients.

How to avoid it?

Bleeding can only be avoided at the mixing stage, which is primarily done at the readymix batching plant if it is wet mix concrete. Concrete bleed can be reduced in four main ways:

1. Ensure the cement to water ratio is strictly followed.

The minimum ratio of water to cement for hydration or curing concrete is 0.20. However, it would make concrete very unworkable. Typically, we use a ratio between 0.40 and 0.50. Adding more water will result in free water being trapped in concrete or rising to the top causing bleeding. We can replace water with chemical admixtures to reduce water requirements.

2. Adding more fines aggregates

Sand is a fine particle that can absorb water. If you are using sand to reduce bleeding, make sure that the sand contains finer particles. Usually, sand with a fineness modulus of 2.5 to 2.8 is best. More absorption occurs with finer particles. You may also want to increase the sand content and lower the coarse aggregates, but be aware of the effect on the mixture’s strength.

3. Include supplementary cementitious materials in your mix design

Slag or Fly Ash is extremely fine, sometimes even finer than cement. Adding these to your mix design will increase water absorption. Aside from the enhanced workability, they produce more strength in concrete and cost less in comparison with cement.

4. Include air entrainment.

It is very effective to reduce bleeding by using air-entraining admixtures while mixing at the batching plant. When adding tiny air bubbles to a freshly poured concrete mix, the cement and water need to cover more area in the mix, which reduces the amount of water that can rise to the surface.

5. Reducing transportation distance

If you have to transport concrete mix over longer distances, segregation of water can happen in the mix. In such a case, concrete from a dry mix concrete batching plant is the best alternative.

6. Concrete placement

Dropping concrete by greater distances of more than 1 m, and vibrating it for a long time may cause segregation of aggregates and water. It should be avoided.

Other segregation phenomena in concrete

The primary cause of segregation in concrete is the difference in specific gravities between the constituents. The specific gravity of cement is between 3.1 and 3.6g/cc and for aggregate it is between 2.6 and 2.7g/cc, This difference of specific gravities can cause aggregate separation from the cement matrix and causes segregation in concrete. During the plastic phase of concrete, cement pastes can also separate from the concrete.

#readymix batching plant

Managing your asphalt plant operations better

Owners of asphalt mixing plants have a lot on their plates. The materials for hot or warm mix asphalt are received, stored, and processed. Workers have to monitor the batching plant capacity, data, and safety issues. Developing and adhering to a production schedule can be challenging.

What can put your asphalt plant behind schedule?

These following factors can cause delay:

· Bad weather

· Road blockage causing delivery problems

· Equipment breakdowns.

· Poor mixes and a lot of mix waste

· Lack of communication with the site

Well, bad weather and road blockages are not in your control. The only thing you can do is to take precautions and have an alternate strategy for mitigating them. The equipment breakdown can be handled well if you have good customer care from your pant manufacturer. Go for batching plant manufacturers with good remote technical assistance and repair service.

Owners of asphalt plants face several costly issues, including wasting material due to an incorrect mix, delivering the wrong mix, or delivering the right mix too late. Through communication, automation, software, and cross-training, a plant owner can reduce these risks and increase efficiency. Here are some tips to have better production scheduling on your asphalt plant.

Tips

The communication process

Communicating with each other is the first step. Plant owners can gain insight into what's happening on the jobsite by holding daily or weekly meetings. Brief status reports and action items can be discussed in these short (15-20 minutes) informal meetings. The best way to hare those action items is with a good software program that allows you to do so in a timely and efficient manner. Alternatively, you can hold the meetings on the floor for everyone to hear to take action. The communication process can also be improved using specialised software. By using software, operators can identify and name a mixed recipe and associate it with specific input materials. Communication is improved and errors are reduced because everyone on the team has the latest information.

Bring in the automation

Go for asphalt plants with specialised automation solutions that allow round-the-clock monitoring of plant operations. Automated control systems, machine monitoring systems, and silo safety systems are some of the automation solutions available. Asphalt plant production equipment is continuously monitored using a variety of electronic devices. The devices ensure that a belt scale or material feed bin is functioning properly. Plant operations can be severely damaged by silo accidents. Infrared sensors can be used to ensure that trucks are properly positioned under a silo through a silo safety system.

Better management of logistics

Make sure the job doesn't sit idle while waiting for the mixed asphalt. It is also important not to over-truck the asphalt mix - sending out a lot of trucks whose asphalt will sit idle on the job site. An asphalt plant operator can save thousands of dollars by avoiding this.

The bottom line

It is difficult to keep track of all the variables involved in scheduling asphalt plant operations. An information system gives the plant operator the power of data. Plant workers can ensure on-time delivery of hot mix by using automation and scheduling software. To reduce downtime and increase efficiency, cross-training is essential. Automation is only as effective as the person who implements it.

#asphalt plant

Readymix Concrete

Ready-mixed concrete is created by mixing Portland cement, water, and aggregates like sand, gravel, or crushed stone in a batching plant according to standard specifications. The alternate of Readymix concrete is site mix concrete, which is made at the site using hand tools or small mixing equipment like mini cement mixers. There are three types of Readymix concrete.

1. Transit Composite Concrete mix:

The transit composite concrete is often referred to as dry-batch concrete because all of its essential components are immediately loaded into the truck mixer. On the truck, the mixer drum is rotated at the charging speed during the loading process and then at conventional mixing speed afterward.

2. Shrink Mixed Concrete mix:

A truck-mounted drum mixer mixes a portion of the concrete in transit and the rest in the concrete plant mixer. The time of mixing carried out at the central mixing plant determines the amount of mixing required within the transit mixer.

To determine whether drum mixers mounted on trucks should be used or not for mixing, tests on the workability of concrete are conducted.

3. Central Mixed Concrete:

This process, also known as central batching, involves adding concrete to a truck right after mixing has been completed. These plants are also called wet mix plants or pre-mixed plants. Occasionally, non-agitating units or dump trucks will also be used, if the travel distance is short.

Materials used in ready mixed concrete:

Aggregates:

As important components of concrete, aggregates account for 70–80% of its volume. According to their size, aggregates are divided into two categories:

· Fine aggregate

· Coarse aggregate

With a dimension of over 4.75 mm, it is considered a coarse aggregate. With a dimension of 4.75 mm or less, it is considered a fine aggregate.

Cement:

The four main components of cement are Dicalcium Silicate (2Ca0 Si), Tricalcium Silicate (3Ca0 Si02), Tricalcium Aluminate (3Ca0 Al203), and Tetra-Calcium Al203 Fer203. These compounds are identified as C2S, C3S, C3A, and C4AF, where C represents calcium oxide (lime), S represents silica, and A represents alumina and iron oxide. Besides alcohol and magnesia, alkalis and other elements are present in small quantities.

Fly ash:

The coal used in plants is mostly composed of combustible elements including carbon, hydrogen, and oxygen, as well as non-combustible impurities (from 10 to 40%) such as clay, shale, quartz, feldspar, and limestone. The average size of fly ash is 20 microns and ranges from 1.0 to 100 microns.

Water:

Water should have a pH between 6.0 and 8.0.

How does it differ with site mix concrete?

· Due to being produced in batching plants in large quantities, Readymix concrete has much better consistency than the site mix concrete which is rather mixed by the hands.

· Readymix concrete allows quicker construction times than the site mix concrete.

· The quality of raw materials can be monitored much efficiently in the case of Readymix concrete.

· By opting for Readymix concrete large quantities of concrete can be supplied to the site.

· Working conditions with Readymix concrete are much safer than the site mix concrete as the later involves direct exposure of labor to concrete dust and other hazardous raw materials

· In the case of Readymix concrete applications, the need for storing aggregates and cement on site is eliminated. This allows better area management of the construction site.

· For smaller projects, where the stationary batching plant is located at a far distance and mobile batching plants are becoming an expensive alternative, site mix concrete can be a better solution.

#dry-batch concrete #wet mix plants

Types of Concrete Batch Plant

A concrete batching plant mixes various ingredients such as water, air, admixtures, sand, aggregate (rocks, gravel, etc. ), fly ash, silica fume, and cement to form concrete. You can batch concrete either by weight or by volume. There are times when ingredients such as Ground Granulated Blast-furnace Slag (GGBS), fly ash, or micro-silica are also added to modify the characteristics of the final product. There is usually very little waste and materials produced by the batching plant. In order to reduce material consumption and waste generation, a concrete waste management plant is also sometimes installed with the plant.

Concrete Batching plants come in two different types:

1. Dry Concrete Batching Plant:

To weigh cement and aggregate, transit mix plants use either manual or digital scales. Additionally, water can be separately weighed and measured, after which it is poured into a transit mixer truck, which transports it to the desired location. When the materials are transported to the construction site, they are blended on the way. Depending on the circumstances of the plant or site, water is added at the location or during transportation.

2. Wet Concrete Batching Plant:

In a central location within the plant, a mixer is used to mix all ingredients with water. As soon as the concrete is mixed, it is poured into the shifting truck that delivers it to the job site. A quick transfer is necessary to prevent the concrete from hardening.

Concrete Batching Plants can be further categorised into 2 categories:

1. Stationary Concrete Batching Plant:

These Concrete batching plants are stationary and located far away from the construction sites. In addition to being easy to put together, stationary concrete batching plants are larger than mobile concrete batching plants. Concrete is transported to construction sites by truck. The trucks have a rotating drum mounted on their back, which keeps on rotating at a certain rate so the concrete mix does not harden. They are extremely efficient and produce high-quality concrete, but the truck must reach the destination on time. Otherwise, the concrete will harden, resulting in inferior concrete being distributed.

In general, stationary batch plants are used for industrial projects with long durations and high demand for concrete.

2. Portable or Mobile Concrete Batching Plant:

There are times when stationary concrete batch plants are situated so far from the project site that transporting the concrete will be inconvenient and more uneconomical. As a result, mobile concrete batching plants, also known as portable concrete batching plants with physical storage, weighing, mixing, and discharging models are increasingly popular.

Concrete mix proportions can be modified by the contractor after the plant is set up. Upon completion of the project, this plant can be moved to a new location. It may be possible to avoid delays due to transportation of concrete as in stationary plants but this type of batching plant has low productivity and capability. The concrete will not achieve its specified strength if it is not weighed correctly, and the durability of the structure will suffer. Batching can be achieved manually for small projects.

Batching plant advantages:

· It is possible to serve a large area with a centralised concrete batching plant.

· Supply trucks can serve residential areas as well as cities within the vicinity of the plants.

· Concrete of better quality can be produced.

· Storage of basic materials on site is eliminated.

#concrete batching plant #concrete waste management plant

Dry Concrete Batching Plant

Dry concrete batching plant, also known as a dry mix concrete batching plant, has sand, gravel, and cement that are fed to a batching plant by numerical or manual scales. A chute discharges all the raw materials into the truck. During the same process, the water is measured, or volume metered, and discharged into the mixer truck. The materials are then mixed in the trucks and delivered to the site.

How does it differ from a wet mix plant?

In a wet mix plant, a concrete mixer is used to mix all the ingredients (including water) in a central location, and the concrete is stirred on the way to the job site to prevent it from setting (using agitators or pre-mixed trucks). In cases, when the site is located quite far from batching plant, the wet mix can become an expensive alternative.

On the other hand, comparatively in a shorter period of time, dry mix provides a more consistent mixture. Usually, in a dry batching plant there will be more variations in the breaking strength from load to load because it is possible to mix cement, stone, and other materials in a systematic manner as opposed to wet mixing. Wet mix plant can prove to be more economical in cases when a single type of mix in large quantities are required.

Dry mix concrete batching plant

The dry concrete plant consists of the same components as a mobile concrete plant and a stationary concrete plant, including cement silos, feeding systems, control systems, weighing systems, and mixing systems. The purpose of cement silos is to store and supply raw materials like cement, sand, and fly ash. In the feed system, aggregates and the mixing system are connected. Consequently, the accuracy of the weighing system affects the quality of mixed concrete since it determines the amount of materials to be mixed. Materials are mixed without water in the mixing system. Because of this, mixer trucks are essential for mixing and transporting concrete. Plants are controlled by control systems. Control rooms can be fully automated. The Eurotec ECD dry mix concrete batching plant has ECS Process Control System software which comes with a user-friendly interface.

Advantages of Dry mix plants

· Concrete can be mixed without water, so it has a higher capacity and lower energy consumption

· When the mixer truck and the dry batch plant work together, productivity increases, and time is saved.

· Due to the mixer trucks arriving at the construction site, fresh concrete can be used.

· Construction time is shortened and productivity is increased.

· It consumes less energy than wet mix plants.

· They are relatively inexpensive to operate.

· It makes mixing concrete more efficient.

· When compared with wet mix plants, there might be shorter period of maintenance needed.

· The dry concrete plant is also automated, as is the case with other mixing plants, such as mobile concrete plants and stationary concrete plants.

· For remote sites, this is an excellent option. The mixer truck may keep the rotation order on the way to the construction site to ensure freshness of the materials, prevent tampering, and hardening of the mixed concrete.

#dry mix concrete batching plant

Why do we need to cool down the concrete

After the pouring of concrete, it needs proper curing. The curing process involves maintaining appropriate moisture content and temperature to achieve the desired strength in it. But have you ever wondered why we need to cure? Hydration is the answer. Hydration produces heat, which dries the concrete, thus removing the water required for proper strength.

Hydration

Cement hydration is the process that occurs during concrete formation. Cement aggregates are chemically bound to water to form a cohesive mass. Hydration is necessary to harden and strengthen concrete.

There are two kinds of chemical processes: endothermic, in which heat is absorbed and the temperature drops, or exothermic, in which heat is released and the temperature rises. When cement hydrates, most chemical reactions take place exothermically. Concrete becomes hotter as a result.

Why do you need to cool down the concrete

During the curing process, concrete becomes harder. Unfortunately, concrete's tensile strength can be reduced by high curing temperatures. Concrete becomes weaker at higher temperatures.

Concrete that is curing expands at higher temperatures, which is part of the problem. Concrete becomes less dense, thereby becoming less strong. It is especially problematic in large-pour settings, where the inner concrete may be substantially warmer than the outer concrete causing non-uniform density and weak spots.

Evaporation of water is another problem associated with hot concrete. The evaporation of water is much more rapid at higher temperatures than at lower temperatures. Consequently, more water evaporates from the concrete as its temperature rises. In spite of the fact that cement hydration relies on water, this can lead to serious problems and prevent some cement from hydrating fully.

During summer, it becomes more important to maintain a cool concrete temperature. In hot weather, workability and finishability are reduced, as well as durability and strength. Therefore, cooling of the concrete is required to have a curing process at lowered temperatures.

How to cool down the concrete

Concrete cooling is usually done by substituting part of the water with flakes of ice. Since flake ice absorbs a lot of energy during the transition to water, it significantly lowers the mix's temperature. A large amount of heat is required to melt the ice. For 1 m3 of concrete, it can be cooled by 1°C with 33kg of cold water, but only 7.5kg of flake ice will achieve the same result.

Usually, for large project sites, flake ice plants are built on the site to supply a continuous stream of flake ice.

Flake ice plants

For most concrete plants, a cold water tank provides the cold water for the flake ice plant. Afterwards, the water is sprayed onto refrigerated drums that are so cold that they instantly freeze it into the ice. Since the drums are so cold, the ice often sub-freezes below freezing levels. To remove the ice from the drum, ice removal tools shear it away in a very thin layer, forming flakes. Flake ice is then placed in special containers that are refrigerated, where it can be taken to chill concrete during pouring. Flake ice can also be used to replace some amount of water in concrete.

Ice plants by Eurotec usually include a containerised flake ice machine and ice storage. Transport, weighing, and dosing systems are often present as well. Since the production and storage units are stacked on top of each other, the entire installation only requires a small amount of space.

#Ice plants by Eurotec

Why should you Invest in Owning an Asphalt Plant?

The term batch mix asphalt refers to the process of preparing the end product of hot mix asphalt in specific batches. Batch mix asphalt plants tend to be more accurate and can prepare different mixes according to the customers' needs. Adaptable modular structures allow the machine to be retrofitted at any time.

Asphalt will be produced continuously in continuous drum plants. These plants usually take up less space and are less expensive to operate. Asphalt mixing plants are usually easy to set up and maintain. Asphalt mixing plants are also easy to reinstall. No matter what kind of asphalt plant is being discussed, it is not a cheap piece of equipment to own. For most construction projects, asphalt plants are rented. There are, however, some advantages to owning one. Here are some of them:

Operational efficiency

When renting asphalt plants, it may have wear & tear and probably not have an updated technology, which affects the operational efficiency. Owning an asphalt plant allows you to alter and improve them to make them work more efficiently. You can limit wear & tear more independently.

There may be rented plants that have no automation capabilities. If asphalt plant operations are automated, there will be less human intervention. Errors will be reduced, and efficiency will be increased. All this automation reduces the dependency on workers - hiring and managing quality and efficient labor is a painful process.

The product can be produced when needed

Owning your asphalt plant has the advantage of being able to use your asphalt immediately when it's needed. In order to get asphalt from a competitor's plant, you have to wait in line. When the asphalt is produced by your own asphalt plant, you are in control.

Protection of the environment

To control pollution, asphalt plants are equipped with bag filters. By doing so, we reduce our impact on the environment. By doing so, we conserve our valuable resources and reduce our impact on the environment.

Putting safety first

The safety of people working in asphalt mixing plants should be a priority. There are all necessary safety features to protect a person in case of an accident at these plants. By reducing emissions, toxic elements are less likely to accumulate in the environment. It is an investment that will pay off in the long run.

A greater degree of precision

When precision is higher, there are a number of direct as well as indirect advantages. Among them are less material waste, better quality, less fuel consumption, and better end products. This ultimately results in better quality control, thereby increasing profits.

The end product of high quality

What we strive for is the quality of the end product. As a result, customers and workers will be happier, resulting in less mental and physical stress. The business will thrive with more profit if more revenue and customer satisfaction are achieved.

Asphalt batching plants are long-term investments. They require planning and adequate manpower to operate. Nevertheless, its benefits are immense, and hot mix asphalt is of excellent quality. It's half the battle if you buy from a good manufacturer who can provide you with good service and spare parts support..

You will be responsible for plant maintenance

It is common for companies to wait until they run into a major problem before setting up routine plant maintenance procedures, which can lead to production halts and leave your customers in the lurch. Maintaining your equipment and systems can have a huge impact on your plant's efficiency and productivity-which means a better return on investment.

#Batch mix asphalt plants

Advantages of Using Asphalt Pavements

Modern society relies heavily on roads for increased mobility of people, goods, and services. Asphalt road surfaces provide many benefits, including cost efficiency, noise reduction, and comfort. Construction and maintenance of roads with asphalt materials can benefit all road users and the environment. Here are the few notable advantages of asphalt roads.

The surface of asphalt is smooth and comfortable

Asphalt road provides the smooth, quiet ride that the public has come to expect from this product. With an asphalt paver, a continuous flow of material moves through multiple layers of asphalt pavement. With this method of construction, repetitive construction joints, noisy surface textures, and blow ups are eliminated.

Asphalt is a cost-effective material

Due to its recyclability, asphalt pavement has a much greater residual value than other pavements due to its long lifespan and low initial costs.

It is easy to reheat and reuse reclaimed asphalt because it contains a lot of bitumen. Since bitumen is the most expensive component of asphalt, reclaimed asphalt is a valuable raw material. These factors make reusing reclaimed asphalt an attractive alternative, especially when the reclaimed old asphalt is transported a short distance. Recycled asphalt material is mixed with virgin materials in asphalt mixing plant using an asphalt recycling system.

Asphalt is a safe material

Using new asphalt technology, surface water is rapidly dispersed and drained, reducing water spray and, therefore, improving visibility for drivers in wet conditions. In addition to reducing blinding spray, porous asphalt reduces the risk of aquaplaning and increases visibility for road markings because it disperses surface water.

Asphalt surfaces with colours or textures mixed in asphalt plant have also been developed recently. These are increasingly being used to make it easier for drivers to identify lanes set aside for special uses, like bus lanes, bus stops, and bicycle lanes.

Asphalt is a durable and long-lasting material

Pavements with asphalt are often built with thick base courses that bear the main load above a granular layer that has not been bound. An intermediate course (binder course) is then placed over the base course. A 30-40 mm surface course follows the intermediate (binder) course. Intermediate and base courses designed, built, and maintained properly remain strong and viable for many decades without ever requiring total reconstruction.

Asphalt pavement can be constructed and maintained quickly

Asphalt pavements are fast to construct and maintain. Motorists can begin using the road immediately after the last roller leaves the construction zone since asphalt does not need a "cure" period. As a result, the road is safer and there are fewer delays. Due to these properties, asphalt roads can be easily opened and quickly re-established almost immediately. It is very important to maintain roads in this manner so that they last longer, provide a smooth road surface for vehicles, and extend the lifetime of the road structure.

Almost 100% of asphalt can be reused

In Europe, asphalt is one of the most recycled construction materials. Pavements made from asphalt are sustainable as recycled aggregates and bitumen can be used.

Asphalt roads reduce noise

Using asphalt surfaces can reduce noise both inside and outside the car, helping to prevent accidents by reducing stress, which contributes to driver fatigue. Compared to all traditional road surfaces, asphalt road has the lowest noise levels, and the development of modern, porous, and silent asphalts has further decreased noise levels.

It has flexibility

An asphalt surface can be 'tailored' - designed and formulated to support the traffic load and climatic conditions of a specific highway. Motorways, urban, suburban and rural roads are made from special asphalt mix solutions whose flexibility is particularly useful when dealing with high traffic loads on bridges. The elasticity of bitumen allows asphalt surfaces to withstand extreme temperature cycles, which is helpful in areas where roads freeze and thaw frequently.

#asphalt plant #asphalt mixing plant

What is Asphalt Recycling

In asphalt recycling, reprocessed pavement is used as recycled asphalt. Previously removed and/or reprocessed asphalt and aggregate pavement materials are called reclaimed asphalt pavement (RAP). Asphalt pavements are removed when they are reconstructed, resurfaced, or utilities are uncovered. RAP is composed of high-quality, well-graded aggregates coated with bitumen when properly crushed and screened. In addition to its ability to be reused over and over, asphalt is a highly sustainable product because it utilises many waste products that would otherwise go to landfills. In the asphalt mixture, rubber, slags, foundry sand, glass, and even pig manure are incorporated, resulting in hundreds of acres of landfill space saved.

By recycling asphalt, towns, cities, municipalities, and other organisations that require large amounts of asphalt can reuse their existing asphalt into new projects. Recycling asphalt is in line with the reduce, reuse, and recycle movement.

Why its use is growing?

There are a few simple reasons why asphalt recycling continues to grow.

· Recycled asphalt is more durable and offers better value! By recycling asphalt, we may be able to save money, allowing us to repair roads and build new ones. Recycling asphalt can benefit everyone in this way. Asphalt prices rise in tandem with petroleum prices. Recyclable materials reduce manufacturing costs, which is good news.

· In addition, recycled products offer environmentally friendly results, as well as meeting and possibly exceeding quality standards. Petroleum-based materials take up a lot of landfill space since they never biodegrade. Adding recycled material to the mix helped reduce the need for newly mined aggregate. When possible, it is best to avoid mining because it is water-intensive and hard on the land. With the carbon emissions associated with the transportation of material to a manufacturing plant (especially heavy rock), aggregates can have a significant impact on the environment.

· Recyclable asphalt is stronger when mixed with recycled content. When Reclaimed Asphalt Paving (RAP) is mixed with virgin asphalt, the resultant product is stronger than one that is entirely new.

How to recycle asphalt?

Asphalt recycling can be done by hot or cold recycling or by full-depth recycling (FDR), which allows worn-out roads to be rebuilt by reusing existing ones. A typical recycling process looks like this:

· A recycling plant (or reclaimer) mixes asphalt chunks and millings with water and additives.

· It takes about 20 minutes for hot mix asphalt to be ready for use after being tumbled and heated. Alternatively, cold recycling uses no heat, thus saving energy.

· Often, bitumen (the glue holding the pavement together) is still able to function as an adhesive.

· The asphalt pavement material can also be produced from fine mineral particles that are generated during production, so natural resources are conserved.

Is recycled asphalt in demand?

Yes. Changing local and state regulations continue to drive demand for reclaimed asphalt. Many countries have updated policies following further evaluation of the durability of RAP mixes compared to virgin asphalt. Additionally, municipalities and construction companies are increasingly realising cost savings as RAP mixes are used more frequently.

Lintec & Linnhoff’s asphalt recycling plants

Lintec & Linnhoff offers two types of asphalt recycling plants: Cold Recycling Plant (CRC) and Hot Recycling Plant (HRC). HRC is the process of hot mix asphalt recycling and involves the use of 60% RAP material. CRC involves cold recycling and uses 30% of RAP content to be mixed virgin material.

#asphalt recycling plants

Warm Mix Asphalt

The temperature at which a Warm Mix Asphalt (WMA) is produced and applied is between 20 and 40 °C lower than the temperature at which an equivalent Hot Mix Asphalt (HMA) is produced and applied. In North America, it is also called Warm Mix Bitumen.

Compared with an equivalent hot mix asphalt, this warm mix asphalt has several advantages due to its lower production and application temperatures:

· Improved working conditions and fewer emissions for asphalt workers.

· Lower energy use and reduced emissions for the environment. By using Warm Mix Asphalt, mixing and paving temperatures are lowered, which results in minimal fume and odor emissions, as well as cooler working conditions for asphalt workers. For every 12 °C reductions in temperature, the release of fumes is reduced by about 50%.

· Manufacturer and Paver benefits: Bitumen is less hardened and RAP is fully compatible

· Paving operations benefits include: WMA can be compacted at a lower temperature than HMA. Producing WMA at HMA temperatures will allow for longer hauling and compaction times. Due to the faster cooling to ambient temperatures, more traffic can be allowed on the site sooner.

Various types of asphalt

Apart from WMA and HMA, there are also other types of asphalt. Let's see the differences between them.

· In cold mix asphalt, aggregate is unheated and bitumen emulsion or foamed bitumen is used.

· The temperature of half-warm asphalt is between 70 °C and 100 °C.

· Warm mix asphalt is produced and mixed at temperatures of roughly 100 to 150 degrees Celsius.

· The production and mixing of hot mix asphalt take place at temperatures between 120 and 190 °C, depending on the bitumen used.

WMA production techniques

Warm-Mix Asphalt (WMA) technologies operate above 100°C, so very little water remains in the mix. To enable full coating and subsequent compatibility at lower temperatures, a variety of techniques have been developed to reduce the effective viscosity of the binder. The most common techniques are:

Adding organic additives

The viscosity of bitumen can be lowered by using different organic additives above about 90°C. A common additive is a paraffin wax produced from the conversion of natural gas. A typical organic additive can reduce asphalt temperatures by 20-30°C while simultaneously improving the deformation resistance of the asphalt.

The use of chemical additives

Bitumen viscosity is not affected by chemical additives. Their role as surfactants is to act at the microscopic level at which aggregates and bitumen interact. Typically, they operate at temperatures between 140°C and 85°C to regulate and reduce frictional forces at that interface. Therefore, the bitumen and aggregate can be mixed and compacted at a lower temperature. Mixing and compaction temperatures may be reduced by 20 - 40°C with chemical additives.

Foaming techniques

To reduce bitumen's viscosity, foaming techniques are applied. Small amounts of water are introduced into the hot bitumen by a variety of methods. For a short period, the water turns to steam, increasing the volume of the bitumen and reducing its viscosity. It is possible to coat the aggregates with bitumen at lower temperatures, and the residual moisture on the construction site allows for the compaction of the asphalt. Both production and paving temperatures can be lowered simultaneously.

Lintec Ecological Processing (LEP95) system

Lintec Ecological Processing (LEP95) system allows the the production of warm mix asphalt with the same reliability and functional properties as Hot Mix Asphalt (HMA). LEP95 allows asphalt mix to be produced at maximum 95-100°C, reducing energy consumption by 40% and lowering overall bitumen and carbon emission by as much as 35%. The WMA produced requires less curing time, so roads can be available faster for traffic. The system can also be easily retrofitted to existing asphalt plants and can produce asphalt with 100% virgin material or 60% RAP (Reclaimed Asphalt Pavement) material mixed with virgin materials.

#hot mix asphalt

Mobile Concrete Plant

Concrete is a composite material made up of several fine and coarse aggregates which bond together with a wet cement paste that hardens over time. This hardening or drying up process is also referred to as ‘curing.’ In the past, lime putty such as lime-based cement binders, were often used with calcium aluminate cement – a type of hydraulic cement which is known to be water resistant.

There are mainly two types of concrete plants which work with a set of different production protocols, namely; - Dry mix concrete plant - Wet mix concrete plant

Choosing a suitable concrete batching plant according to the construction project specifications is very important. Determining the required blueprint to be built and its transportation facilities gives the builder an idea in advance on what sort of equipment's and the type of batching plant that will be most suitable for the project success.

Mobile concrete batching and mixing plant is a special type of plant that integrates the material storage, weighing, conveying, stirring, unloading and automatic control system into a trailer unit. This type of plant only requires a small area to conduct its operations and it has the benefit of mobility to be able to operate at different locations as per the project requirements. Thus, it is a valuable type of mixing unit to possess with any RMC operator. Especially, during time constrained large scale construction projects like the construction of public railway, bridge, port, hydro-power and other projects.

Eurotec Mobiquick concrete mixing plant

With an output capacity ranging from 60 m3/h and 90 m3/h, the Eurotec Mobiquick concrete plant comes with quick installation and dismantling setup. The plant modules are developed for easy transportation and relocation, depending on mode of operations suiting the custom client specifications.

This type of concrete batching and mixing plant comes equipped with an efficient conveying system, a highly accurate and proportioned weighing system. High quality parts for improved performance with world class durability, thereby promising value in the reliability of its parts and components.

Some of the key benefits of a mobile concrete plant is that it’s suitable for short-term projects. These batching plant systems are developed with easy maintenance access to all its levels. Incorporating technology that enables reduced noise and dust levels in all its range of products to choose from with an extensive range of customization options. This model consists of a water weighing hopper, cement weighing hopper, twin shaft mixer, aggregate bins, transport legs, built in control room and wheel arrangement.

Wet mix concrete plants

This type of batching plant system consists of a modular concept in the design of the batching plant, which do not require too much space to assemble and operate, as well as facilitate the disassembly and assembly with ease. This type of plant also helps to reduce costs and increase working efficiency. Modular wet mix concrete batch plants also happen to be a preferred choice for emergency repair and constructions that require emergency projects to be completed in a short period. Thus, assisting with early completion, saving time and labour costs.

The working principle involved in a wet batching plant includes a combination of sand, raw aggregates, cement, and water together to form concrete that is ready for use and mobile in the least possible time. Wet mix concrete batching plants have a wide range of applications as they can produce high quality concrete mixture.

#Mobile Concrete Plant #mobile asphalt batch plant

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