Intelligent Compaction (IC) refers to the compaction of road materials such as soils, aggregate bases, or asphalt pavement materials using modern vibratory rollers equipped with an integrated measurement system, an onboard computer reporting system, Global Positioning System (GPS)-based mapping, and optional feedback control. IC rollers facilitate real-time compaction monitoring and timely adjustments to the compaction process by integrating measurement, documentation, and control systems. IC rollers also maintain a continuous record of colour-coded plots, allowing the user to view plots of the precise location of the roller, the number of roller passes, and material stiffness measurements.

Trends in IC
Compaction is one of the most important processes in roadway construction. It is necessary in order to attain high quality and uniformity of pavement materials, which in turn better ensure long-lasting performance. Pavement materials often possess optimum densities that ensure adequate support, stability, and strength-achieving these densities uniformly is key, and IC aids this process. Current procedures using conventional compaction machines may result in inadequate and/or non-uniform material densities, which can be one of the major factors in premature pavement failure. IC helps users overcome this issue by optimising the compaction process. IC rollers are vibratory rollers equipped with instrumentation fed to a documentation and feedback control system that processes compaction data in real time for the roller operator.

According to Amit Gossain, Executive Vice President - Sales, Marketing and Business Development, JCB India, IC is presently one of the most significant technologies that have been introduced in the Indian road construction industry. It offers the desired quality of work and also increases the overall performance of the machine. Ajay Aneja, National Head - Sales, CASE India, says, ?With the use of intelligent compaction system, we can monitor the compaction value (indicative) to avoid over compaction. It monitors the layer temperature to maintain optimum level. Fuel level and location can also be tracked to prevent theft or misuse of the machine.?

IC has not received due importance in the Indian market. Gossain observes, ?In India, it has received minimal penetration till now due to lack of awareness among contractors and unavailability of skilled manpower. However, as specifications for road-building become more stringent and with project sizes getting bigger by the day, we are optimistic that use of IC technology will gain popularity.?

Aneja says, ?IC is a technological innovation with several advantages over conventional compaction technologies. However, being still at a nascent stage, it suffers from lack of adequate knowledge among engineers. The equipment used in small-scale projects are selected by contractors. Hence the recommendation and acceptance of IC systems has to come from the contractor fraternity, who have to educate themselves and understand the advantages of this technology.

Ramesh Palagiri, Managing Director and CEO, Wirtgen India, also expressed his optimism on IC as he says, ?The Indian Roads Congress published IRC-097 documented for IC system, which specifies the requirement of IC for Indian conditions. We expect this will be one of the tender specifications in the coming days. This will help improve the quality of roads.? He further adds, ?Hamm compactors can be supplied with IC system which meet IRC-097 requirements. It is important to train the operators/contractors for the usage of this system and the data generated should be integrated to the concerned departments.?

?IC system is going to be a pre-requisite at many places in future. It helps to get the right output by optimally using the machine and delivering the desired 90 per cent compaction,? says Rajinder Raina, General Manager - Marketing, Escorts.

Instrumentation
The precise location of the roller, its speed, and number of passes over a given location are mapped using GPS or a similar system. These mapping systems are commonly used to establish grade and to control other pieces of equipment. To determine the effectiveness of the compaction process, compaction meters or accelerometers are mounted on or above the drum to monitor applied compaction effort, frequency, and response from the material being compacted. The methodology used to calculate material response is often proprietary. Soil response can be described by a compaction index or stiffness/moduli values. Project test strips are often calibrated in order to correlate the compaction index or stiffness/moduli values to conventional in situ measurements such as material modulus or density. Additional temperature instrumentation for asphalt IC rollers allows the user to monitor the surface temperature of the asphalt pavement material. This is critical as vibratory compaction within certain temperature ranges can cause adverse effects.

Documentation and feedback control
One critical feature IC rollers possess is a system to collect, process and analyse the measurements in real time. This feature allows the roller operator to view a colour-coded map that instantly displays interaction between roller location and number of passes, cumulative compaction effort, and material response. Optional feedback controls can utilise this data to continuously adjust the force and frequency of the drum in order to maximise efficiency and effectiveness. The display on the IC roller alerts the operator when the desired compaction is obtained, eliminating unnecessary passes. If problem areas are detected, the system will notify the operator when additional roller passes will not result in desired compaction. It will then document the problem areas for further analysis.

Some IC rollers - namely some dual drum rollers for asphalt pavement materials ? are not equipped with accelerometer-based measurement systems. However, there are still many benefits from collecting the IC roller pass data and asphalt mat temperatures.

Improved performance
A compactor?s operating weight, vibration with its characteristic variables of frequency and amplitude, result in generating optimum forces of compaction. Engine, which is the heart of the machine, needs to be powerful along with optimum fuel consumption. Ease of operation, serviceability and operator comfort also play a vital role in productivity over a period of time.

The equipment uptime is one of the major factors which customers consider while deciding on the machine. So manufacturers are focusing more on improved machine performance since time-bound projects need reliable machines. Given below are the features incorporated with the compactors from leading manufacturers that improve overall machine performance.

JCB

• Advanced engine: JCB 4-cylinder water-cooled ecoMAX engine.
• Water system performance: Use two water pumps - one for the regular use and the second one as a backup. The water is filtered through three separate filters to avoid repetitive chocking of the nozzles. Water tanks (1,040 litre) provided with the machine which reduces the frequency of the water tank refilling.
• Gradability: In heavy tandem rollers, 40 per cent and in the drum drive soil compactor 55 per cent

Hamm (Wirtgen) 

• Powered by Cummins engines and hydraulics from Bosch
• Designed to ensure better steerability.
• Inbuilt frame design ensures high curb clearance and go closest to the curb height of 700 mm
• Crab steering option to offset during operation
• Tandem rollers are equipped with two plastic water tanks mounted on front and rear of the machine. One main and one auxiliary water pump are provided for trouble-free operations, plastic spray nozzles for rust-free operation
• Three-stage filtration to take care of the contamination in water
• Superior climbing ability to operate in higher gradient locations and can climb to gradient of maximum 54 per cent with additional drive for the drum. This makes the machine suitable for operations in dam/irrigation site applications where higher gradability of compaction is required.
• Weight distribution between the front and rear part of machine ensures that desired gradability is achieved.

CASE

• Compaction forces: For tandem rollers, the CASE 752 develops forces of about 25 tonne while CASE 450DX develops 6 tonne. The CASE 1107 DX features a compaction force of 34 tonne which is the highest in its class.
• Steerability and curb clearance: Turning radius is the lowest in their class which results in high manoeuverability in constricted spaces
• Drum shell thickness: Drum shell thickness for CASE 752 is 17 mm while for CASE 450DX its 12 mm. The highest in its class drum shell thickness for CASE 1107DX of 32 mm.
• Advanced engine and hydraulics: Equipped with engines that deliver excellent fuel efficiency. Currently the engines used in vibratory compactors comply with BS III emission norms.

Escorts 

• The engines are manufactured by Escorts, turbocharged and conform to BS-III norm, deliver best-in-class fuel efficiency. The hydraulic circuit is close loop type with hydraulic pump, other aggregates sourced from the best in the world.
• EC5250 soil compactor has the highest gradability in its class.
• Water system in TVRs comprises a roto moulded plastic tank with high pressure pump and quick coupling nozzles with auto sprinkling cut-off is standard

ACE

• Fitted with Kirloskar 4R1040 BS-III turbo charged engine
• Dedicated water pump and tank for individual drum with flow of 12 lpm in tandem roller, filtration system to avoid blockage of nozzles.
• Gradability of 45 per cent is the best-in-class of soil compactors for standard machines

Improving O&M cost
Initial cost and O&M costs are two major cost components of a machine. Lower O&M cost of a machine can lead to increased profitability. So all leading OEMs are focusing on improved O&M cost of their machines.

JCB uses IC technology as an optional feature in its machines. Explains Gossain, ?We name it as Compaction Measurement System, which can be installed as plug and play. We also provide interim solutions such as a Compaction Meter which results in cost saving due to optimisation of the number of passes to achieve compaction.? JCB range also has a unique scavenging system to clean the air filter. The dash board gives indication of fuel or air filter malfunctioning.

According to Ramesh, IC system can be integrated with the machine control system and is designed to achieve optimum compaction with minimum number of passes, so as to reduce the overall operating costs. He says, ?Hamm offers ?HAMMTRONIC? and ?HCQ? technologies as options with their compactors.?

HAMMTRONIC is a machine management system which links, monitors and controls machine functions and makes it easy to operate. The information needed for the driver is displayed on an information display on the console. This centralised and regulated function prevents human errors and also enables the operator to concentrate on optimum rolling results. HCQ ensures even compaction, minimising number of passes, prevents over-compaction or loosening, and soil test conventional method to check load bearing capacity is not required.

?With these systems, the quality is not dependent on operator skills but is system driven and consistently achievable,? opines Ramesh. According to him, improved design of fuel and air filters are available on all Hamm machines and have a higher life. Usage of these filters increases the service/maintenance intervals and thereby contributes to reduced O&M cost of the machine.

Air filter change is recommended only if frequent clog indication appears on the control panel. In all Hamm machines, the main structures are made of tensile steel, which improves the reliability and also meets higher ambient requirements. About the design of air filters/fuel filters, Aneja says, ?The engines used in vibratory compactors are turbocharged, having waste gate control mechanism, Internal Exhaust Gas Recirculation (IEGR) system to minimise the emissions (like NOx, CO and CO2) to protect the environment.?

Improved reliability of the machines play a vital role in the O&M cost. ?Largest in its class drum shell thickness ensures longer drum life. Robust design with ease of operation ensures maximum up time. Also, a large population of more than 7,500 machines working pan India keeps the service and parts readily available,? Aneja observes.

According to Raina, compaction involves high level of understanding of the process to deliver the desired compaction. The operator?s expertise on this front as also his machine operation skills makes a huge difference in the operating cost.

Raina is of the view that compactors on an average do not clock more than 2,000 hours in a year and mostly incorporate high-end technology that does not ask for too much of maintenance. ?However, regular walk around, preventive and other check-ups including oil and filter changes at the prescribed intervals would keep the machine in good health,? he feels. He also advises for a little extra care on the air filter as the machine works in dusty environment.

Safety and comfort features
Says Gossain, ?Operator platform is mounted on four viscous mounts which isolates it from the drum and chassis vibration. This platform ensures the operator is comfortable while operating the machine, thus increasing operator?s efficiency. Articulation joints in all compactors are maintenance-free with self-lubricating bearings. This ensures longer life and foolproof operation. The control panel, joy sticks, seat and the levers are ergonomically designed, ensuring ease of operation to the operator. JCB engine is proven to be having the lowest noise levels in its class. In case of the soil compactors, a glass is also provided behind the operator seat, resulting in further reduction in the noise levels. ROPS/FOPS and other safety features are optional in our machines.?

Hamm compactors are equipped with isolated operator platform mounted on shock absorbers so that the vibrations are reduced. The operator platform is with antiskid material to ensure operator safety. The sliding seat console for operators and excellent drum edge visibility are some striking features which make the machines easier to operate. Hamm soil compactors are built with patented design of three-point articulation joint. This connects the front and rear end of the compactor, enables excellent directional stability, provides driver safety on difficult terrains and also adds to driver?s comfort. This also increases the operator efficiency. The engine compartment is closed with FRP hood in Hamm compactors which reduces the noise levels.

CASE also offers a range of features that help improve operators? safety and comfort. The new two-post canopy structure provides excellent visibility, which is further improved to the rear by the new sloping hood. The 90o clockwise rotating seat and the operator platform isolated from vibration make for smooth and comfortable operation. The wrap-around railing contributes to better operator safety. Robust four-point contact articulation joint is very low maintenance with the best-in-class turning radius. Along with each machine, CASE provides operators and spare parts manuals which guide the operators and customers about correct use of the machine. To minimise the noise levels and vibrations, CASE compactors are equipped with anti-vibration pads at critical locations. Engines are fitted with turbochargers and with synced fuel injection timing and optimum operating temperatures.

Raina elaborates on the safety and comfort features in a compactor, ?All-round visibility through better machine profile is the key. The noise and vibration at the driver?s seat are very important as the drums of the compactor vibrate. Suspension in the platform helps cushion the vibrations and thereby reducing the fatigue of the operator. Neutral start mechanism makes it foolproof/accident-proof.? Speaking about the operator?s comfort, Neeraj Bhatia, Business Head, ACE, says, ?Operator?s seat can be adjusted sideways as well as rotate by 180o. It gives flexibility to operator for better visibility (1 m x 1 m in front and rear).

Skill development
Productivity is not only achieved by machine alone but also by the operator skills. Operator knowledge is very important in the selection of the right amplitude, frequency, modes etc for efficient compaction. Change in settings helps optimising fuel consumption and also to achieve better quality of compacted surface. ?To keep the operators and customers up to date with the latest practices and techniques, we have a dedicated training centre which organises training programmes all-round the year,? says Aneja.

Wirtgen also focuses on operator training and there are periodic trainings conducted. Says Ramesh, ?We at Wirtgen are continuously engaged in providing training for the customer operators and concerned associates.?

Market scenario
According to Gossain, the estimated market for compactors (heavy and small tandem rollers) is around 2,500 units a year. ?The past couple of years have seen a decline in the demand due to various reasons. However, given the investments planned by the government, especially in the roads and highways sector, we are hopeful that the demand will soon pick up in the coming months,? he adds. According to Raina, the annual market for compactors is currently at 2,000-2,500 in which 10 tonne soil compactors and TVRs comprise 90 per cent, while the balance is mini tandem rollers and a few PTRs.

Aneja provides a detailed picture of the market as he elaborates, ?The market for soil compactors, which varied between 46-51 per cent of the total compaction equipment sales represent 45 per cent of the market at about 1,100 units. Demand for tandem rollers remained at the same level of 1,150 units in 2013 and 2014, but its contribution in total sales rose from 45 per cent in 2013 to a peak of 48 per cent in 2014. Sales of compaction equipment grew by nearly five per cent in the first half of 2015 compared to the same period in 2014. Off-Highway Research forecasts the demand to reach 3,000 units by 2019.?

The road ahead
All leading players see roads and highways sector as the major growth driver for the compactor market. According to Gossain, apart from roads and highways, projects like 100 smart cities wherein the government plans to spend Rs 48,000 crore, the demand for the road construction equipment will further increase in the coming years. He adds, ?Currently, the compactor industry is expected to grow at a pace of 10 per cent in 2016 and further to 15 per cent from 2017 onwards. However, the government needs to ensure implementation of key projects to achieve this expected growth.?

Ramesh also sees roads and highways a major growth driver as he says, ?Last year has been very good due to a number of road projects been awarded by the new government. Around 3,000 km of projects have been awarded in 2014-15 and for 2015-16, the target is 5,000 km. This directly would be a boost to the road equipment manufactures and the scenario looks very positive.? He also observes that equipment are expected to be upgraded with higher technology to improve the performance and productivity. More operator safety features might be included in the regulations and norms.

Raina sees a market growth of 12-15 per cent in the near future. ?The good news is that the standards of compaction are going to be stringent which will fuel the demand for vibratory compactors,? he adds. Bhatia says, ?Government has already awarded 8,000 km of road projects, while the dedicated freight corridor construction from Ludhiana to Kolkata and Delhi to JNPT near Mumbai is in full swing. In the coming years, the road projects are expected to increase to 10,000-12,000 km per year. In this scenario, there are good growth potentials in road equipment sector.?

Aneja is also optimistic about the roads and highways sector when he says, ?With the recent announcement to develop 15,000 km of national highway at a cost of Rs 1.9 lakh crore and the plan to upgrade eight select national highways to world-class express highways, auger extremely well for this sector in the coming years.? Compactors industry is already on the road to rapid growth and there is more to come in the near and distant future. The pressure to perform at the best-in-class efficiency and the lowest operating cost will be the most significant challenge to the road builders. Intelligent Compaction will come to their rescue and become an industry norm in the near future.

Major benefits of IC

• Improved in place density and uniformity
• Increased productivity
• Reduction of highway repair costs
• Continuous record of material stiffness values
• Identification of non-compactible areas
• Improved depth of compaction

Compactors with specifications