By Jayashree Mendes
Redevelopment projects that kick started in Mumbai, the country’s biggest realty market, are now happening in almost every major city in the country. The availability of specialised equipment for demolition and breaking not to forget methodology to recycle the aggregates is adding to the reconstruction spree.
Redevelopment is seeing a spurt in cities where land availability for new development is a constraint. The unique challenges presented by Indian cities in the form of congested by lanes, has meant that controlled demolition is the only way out. Specialised demolition equipment is finding increasing application in a majority of jobs.
Vipin Bhatia, product manager, construction tools division (hydraulic attachments), Atlas Copco India, says, “With the rise in construction activities all around, the application of demolition tools have jumped exponentially. In the construction and demolition tools business, Atlas Copco develops, manufactures and markets solid body, medium and heavy breakers. Specifically the SB solid body breaker range integrates the percussion mechanism and guide system into one single block of steel making these breakers extremely compact and easy to handle. The SB breakers have a sleek body with a reliable soul. In terms of product features, the breakers are uncontested on reliability, flexibility, high productivity and low maintenance.”
Hydraulic breakers are used in a majority of demolition jobs. They frequently find demand in the highways sector and are used for asphalt cutting and removal. Hydraulic breakers are also used extensively for high-reach demolition jobs, which are common in metros. Atlas Copco, Sandvik Construction and Volvo CE are among the leading players that offer hydraulic breakers in India.
Sandvik Construction’s vice-president, Harinderjit Singh, says, “We have a range of hydraulic breakers suitable for 0.5 tonne class base machine to 100 tonne base machine. We have a range of cutters, crushers, pulverisers, multiprocessors and grapples too to suit our customers’ needs.”
In addition to hydraulic breakers, grapples or pulverisers are also finding increasing application. Rotating grapples that can rotate 3600 mounted on excavator booms have made demolition jobs a lot simpler. They help in cutting down on costs since there is little need to reposition the excavator. Similarly, pile cutters are also in demand. They are used for demolition of foundation piles. They have gradually replaced the earlier jack hammers that were earlier being used for such jobs in the country.
Nagpur-based Amit Uniyal, CEO of Anika Drill Services, says, “We began using demolition equipment 12 years ago and find it a better option than manual labour. Not only is it safe, but the output is faster too. At new construction sites where any type of changes is required, structural engineers and architects don’t allow us to use demolition hammers because of the vibrations they cause to the structure. Instead we take recourse to using diamond cutting tools like handheld saws and wall or wire saws.”
Vijay Pandey, vice-president, Bosch Power Tools, explains, “The latest advancement in the demolition and breaking equipment is the ‘vibration control’ feature. It reduces arm vibrations. The demolition hammer now has an enlarged air cushion that reduces vibrations at the point of origin without reducing the power of the demolition hammer. Also, the damping elements at the upper guide elements and at the bearing shaft ensure that the vibrations reduced in the first stage are absorbed further.”
Several new technologies have made their way into India. Rotary drum cutters that are used for trenching hard stone are also being widely used. These versatile attachments can be used for pro-filing, pile head cutting, trenching and general foundation excavation, apart from finding use in demolition jobs.
In another step towards assured performance, quality and reliability, Atlas Copco demonstrates its expertise in on-site crushing with its hydraulic bucket crusher.
The bucket crushers are an innovative answer to crushing requirements on today´s worksites. Using a rig-mounted bucket crusher, all types of inert demolition material can be crushed and re-used on site. This process requires less mechanical equipment, less transportation and dumpsite cost and only one operator who handles the demolition attachment as well as the bucket crusher.
Just as in the case with specialised equipment used for demolition, there is also a wide variety of equipment available for recycling of aggregates nowadays. On-site recycling with bucket crushers is a good example for recycling equipment. Bucket crushers can be used as an attachment with both backhoe loaders and excavators. They help in recycling concrete and stone, and that too on site, hence eliminating disposal of huge quantities of demolished material, apart from helping saving space on site, transportation costs, and labour.
Bhatia of Atlas Copco says that certain criteria need to be considered when purchasing equipment. “For instance cycle time of the equipment, load taking capacity and the impact force of the equipment must be looked into. The type of material to be demolished then offers insight into the equipment needed at the site. Reduced cycle time helps to cut the material fast, and in case, the carrier takes the higher load, the biggest equipment helps to finish the job.
Sandvik Construction’s premium primary breakers come with Ramdata II as standard equipment. The Ramdata II provide digital and secure information on applications, usage, cycles, working hours, past service history, etc. It has provision to upload the data on the website and create complete history of the breakers. This will ensure that the breaker maintenance is done on time. The usage and performance shall be optimised on the basis of the digital information.
In terms of warranty, Atlas Copco claims that it is the only manufacturer to offer extended warranty which covers the four main components of the hydraulic breaker: Piston, lower hammer part, cylinder and cylinder cover, for 36 months from the date of commissioning, which in turn covers 75% of the cost of whole equipment.
Companies are adopting safety precautions and most of them have a comprehensive manual along with the tools. Pandey of Bosch Power Tools lists out a few:
*The work area should be well lit and not contain explosive or inflammable materials
*When using the power tool, do not touch grounded surfaces like pipes, radiators and refrigerators – there is a high risk of electric shock
*Always hold the tool with the insulated gripping
*Unplug the tool immediately after use *Always read and understand the tool’s operator manual, tool markings and the instructions packaged with the accessory before starting any work.
Singh of Sandvik Construction says that the company’s breakers reduce maximum possible vibrations to equipment and operator cabin. “It reduces operator fatigue due to continuous operation of the breaker. The box type housing, extremely high quality isolation mechanism and very few holes in the housing due to superior breaker design ensure that breakers are one of the most quiet (noise free) breakers in the world.”
Uniyal of Anika Drill Services explains the type of equipment that will transform the demolition/breaking industry.
“The hydraulic jaw crusher and the hydro demolition that runs on water and helps in cutting and chipping concrete is new in India. They can do the job well and are efficient.”
While some in the industry consider hydraulic breakers as passé, they praise the preference for pneumatic and electric machines. “Pneumatic breakers can be used on semi-solid rock, asphalt cutting as well as concrete, but the vibration levels are high. They should be preferred in complete structure demolition,” says Uniyal. “Controlled blasting will always remain the cheapest method of demolishing complete structures.”
Singh of Sandvik Construction has worked out a technique that will reduce the total cost of ownership for customers. He says, “Our breakers are small in size for carrying out particular jobs. This means the customer may have to choose a smaller excavator for a particular application compared to other breakers in the market. And this translates into big savings on investment of excavator and diesel consumption.”
Alternatively, if customers have a particular excavator and use equal size breaker, then the job shall be completed well before time. Moreover, Sandvik Construction’s equipment requires fewer number of spare thus leading to lower inventory cost. Its latest technology like VIDAT, patented retaining pin design, etc. ensures that the breakers work trouble free for longer period of time.
These days there are also specialised magnetic separators available for removal of steel reinforcement. The magnetic separators typically contain conveyor systems where the debris passes through above when magnets are placed at strategic locations. The latest generation magnetic separators work in two ways for sorting construction and demolition waste.
While in the first type there are over band magnets that automatically remove iron and other ferrous materials as they are being conveyed through the system, the other system works by ‘repelling’ nonferrous metals. The second type is widely used when the recycling is for nonferrous metals such as silver, copper or aluminium.
The powerful band magnets ‘repel’ these nonferrous components while allowing the other metals to continue in their onward journey in the conveyor.
Crushers are another piece of equipment that plays a key role in the recycling process. They are used for crushing and recycling concrete, asphalt, brick scrap, etc. The trend these days is towards mobile jaw and cone crushers which can be taken to the actual construction site, where the recycling process begins. Vibrating screens with multiple decks are another important piece of equipment that is used during the aggregate recycling process. Sandvik Construction has also taken to the green route and about 98% of its breaker parts are recyclable by value. New technologies are being introduced in the market keeping in mind the safety and performance of machines.
Manufacturers are spending enormous amounts of money in development of machines that are efficient, powerful, noise and pollution free and importantly one that requires least man power.