Improving efficiency
Batch mix plant is the most widespread type of asphalt plant in the world, which guarantees the highest level of flexibility in production and quality of the finished product.

The infrastructure and construction sector has witnessed rapid growth during the past few years, which has driven the demand for asphalt mixing plants. The global asphalt mixing plants market is driven by fluctuations in the infrastructure sector, which is the key market for asphalt mixing plants.

Asphalt is a dark brown to black, thick mixture of heavy hydrocarbons that is a residue produced by crude oil refineries and through the destructive distillation of coal. It is primarily used for laying surfaces such as roads and playgrounds. Other applications of asphalt are found in waterproofing solutions and construction of parking lots and pedestrian paths. Asphalt mixing plants are machines consisting of a cluster of electronic and mechanical gears in which hot mix asphalt is produced. There are three main types of asphalt mixing plants, batch mix, drum mix, and continuous mix. The raw materials used in the manufacture of asphalt mixing plants are mainly iron and steel.

Batch mix plant is the most widespread type of asphalt plant in the world, which guarantees the highest level of flexibility in production and quality of the finished product. The batches depend on the type of production: In every 40 to 50 seconds, a complete batch is produced, after all the individual components have been weighed and metered separately.

This type of plant is a must for producers who work for several clients at the same time, because the specifications can be easily changed, while maintaining a high level of mix quality.

In continuous asphalt drum mix/hot mix plant, there is no interruption in the production cycle as the rhythm of production is not broken into batches. The mixing of the material takes place inside the dryer drum which is elongated, as it dries and mixes the material at the same time. Since there are no mixing tower or elevators, the system is therefore considerably simplified, with a consequent reduction in the cost of maintenance. The absence of the screen however makes it necessary to have precise controls at the beginning of the production cycle, before the aggregates are fed into the dryer and before they are consequently discharged from the dryer as asphalt mix.

Atlas industries, Benninghoven, Kaushik Engineering Works, Quality Products (India), Linhoff India, Akona Engineering Private Limited, HP Tiles Machinery, Solmec Earthmovers, 4B Construction Corporation, and Arky Construction and Supply are some of the prominent names in the global asphalt mixing plants market. Benninghoven is innovating its product mix and launching mobile asphalt mixing plants to ensure greater efficiency in terms of operation as well as mobility.

Government has announced investment of more than Rs 102 trillion across various infrastructure projects in the next five years. For the road sector alone, the government is investing Rs 2 trillion this year. The amount of investment for the next year will increase to Rs 3 trillion. Within the next five years, the total government spend on the road infrastructure will be about Rs 17 trillion. This is going to see momentum in rural roads as well as state and national highway construction. The infrastructure investment plans will also include development of airport and port infrastructure. All these will see more requirement of asphalt mix in large quantity.

In asphalt batch mix plants, the mixer with double arms and paddles means the mixing quality is undoubtedly better when compared with continuous plants because it is forced mixed. This feature is particularly important when dealing with 'special products' (porous asphalt, split mastic, high RAP content, etc), which require a high level of quality control. In addition, with 'forced mixing' methods, the mixing time can be lengthened or shortened and thereby the mixing quality can be varied, depending on the type of material being produced.

VÖGELE is the world market leader in asphalt paving and offers a right paver for every application with various combination of different paving widths and also offers state-of-the-art Power Feeders especially for the large-scale job sites to offer reliable, uninterrupted transfer of mix to the pavers.

Large roads, such as motorways or trunk roads, are the best applications for mobile feeders. The Power Feeder from VÖGELE is perfectly tailored for use when paving “hot to hot” with two pavers. The offset technology is also ideal for filling the spaces between safety barriers on motorways or long-distance roads quickly and economically. The mobile feeder also demonstrates its strengths when it comes to surfacing footpaths or cycle paths. With its pivoting conveyor, it can travel on the main road and conveniently transfer mix to a small or compact paver on the cycle path. The VÖGELE Power Feeder is also used in an InLine Pave train laying binder and surface courses “hot on hot” in a single pass.

Dr Hans-Friedrich Peters, Executive Vice President of Ammann’s Plants Division, says, “Asphalt producers might be surprised by how much they can accomplish with their existing plant. A very easy first step is to upgrade the control system. A modern control system can have a significant impact on efficiency, and that cuts across many parts of the process. Improved efficiency will lessen fuel usage, emissions and material waste. And the as1 is the best in the business at doing exactly that. Training is another immediate step that can be taken. The best plant and control system in the world will underperform if the operator is unable to leverage the built-in value.”

“Another option is a more comprehensive retrofit. It still costs a fraction of the price of a new plant and is compatible with products made by Ammann and other manufacturers. A retrofit has a host of options you can choose from, including recycling solutions. A retrofit enables the use of foam bitumen, waxes and other additives. Special bitumen and alternative mixing cycles can be utilised as well,” Dr Peters.

Sarvesh Prasad of TIL Ltd, describes the transitions in asphalt mixing, “Over a decade, there has been a gradual shift from small capacity plants to higher capacity plants, and with the movement towards higher capacity plants, stricter control on mix design and emission norms has also become a priority. Of late, plant capacities of 160 TPH and above are much more in demand as these projects have lesser time for execution. Thus, the work needs to be completed much faster and expeditiously. The major shift in technology was initiated by the National Highways Authority of India (NHAI) and Ministry of Road Transport and Highways (MOSRTH) when the infrastructure boom started in India in the 90s. At that point in time, the batch technology was preferred to the drum-mix technology with the objective of producing consistent mix and quality roads. The drum-mix technology is still in use in India and is predominantly used in the Pradhan Mantri Gram Sadak Yojana (PMGSY) roads and state highways.”

Prasad adds, “Drum-mix technology has evolved over the last couple of decades and many countries have adopted this technology wholeheartedly in view of the inherent benefits this technology offers over a batch plant.”

“The success of double-barrel technology globally is a classic example of the evolution of the drum-mix technology. The capability of the equipment to use up to 50 per cent RAP without any modification and the ease with which the plant can be operated is the reason for the success of the double-barrel technology. In India, this technology has been approved for use by NHAI and the motivation to use RAP with ease is encouragement enough for a customer to embrace this offering, as it would substantially lower the cost of road construction and also help preserve the environment. As has been proved in many countries, the state-of-the-art drum-mix technology will pave the way for the future in India as well. Further, with a retrofit called Green Pack, this plant can even produce warm-mix asphalt and has been successfully used in a few projects in India,” says Prasad.

A spokesperson from Safari Construction Equipments, pointed out, “You cannot define key market trends in the asphalt plant business like you define in financial markets. The developer chooses the technology and capacity of the plant based on the ?need? for a given project. The decision on the capacity of a plant is mainly driven by the quality of asphalt required, and the timeframe for completion. Broadly, the trend is to go in for a 120-160 TPH plant for EPC projects of less than 50 km in length. For larger projects, the preference is for 180-260 TPH capacity.”

“Asphalt-mixing technology has come a long way in India over the past 25 years from hand-mixing to sophisticated batch-type mixing plants. The important input material for good-quality asphalt mix, for good-quality roads, is the aggregates. This is the main area of concern in India because the contractor has to source aggregates from different quarries. This makes batch-type plants more suitable to ensure end-quality, because the asphalt batch plant has a multi-deck screen to precisely screen and segregate the input material as per the recipe required for the pavement design. Hence, we have seen that, for higher- and mid-value road projects where the investment is to be protected by building good quality pavements, the batch-type plants are being recommended more and more. Warm mix is still in the initial stage in India, but has big potential to save energy and protect the environment,” offered more clarity is the Safari spokesperson.

With environment-friendly technologies gaining prominence in the construction industry, recycling will play a major role and asphalt plants that can handle more RAP and waste materials such as plastics along with asphalt will drive the market towards greener future.