The path widens. In 2007 Volvo Construction Equipment became a big player in road construction. Fiona McLelland reports on how a segmentation approach is helping maximise the advantages of a complete range of products for road builders.

"No other competitor can offer the complete package," says Murali, the enthusiastic vice president of Region Asia's Road Machinery business line. While other niche manufacuturers provide market-specific machinery, they do not have the full range of general construction equipment used throughout the process, such as wheel loaders, articulated haulers and excavators, Murali explains.

The acquisition of Ingersoll Rand's Road Development division in May 2007 allowed Volvo Construction Equipment to offer highway-specific equipment, as well as traditional construction equipment that are also needed in the road building process.

"The fact that we can offer the full range of machinery definitely adds value for us," says Murali. "And through segmentation we will have the opportunity to improve technology within road construction. We are striving to become the leaders in technology in the road segment by fully understanding each stage of the road construction process - and using that knowledge to help our customers by developing better machinery."

Complementary to the segmentation approach, Volvo Construction Equipment owns the Rasta Center for Road Technology in India. The institute for knowledge and training, which has accreditation from a local university, provides a valuable service for the road construction industry, says Murali.

"As Rasta is an independent institute Volvo Construction Equipment never promotes its own machinery, but we can provide a wonderful service for our customers. Through the institute we can provide training and knowledge about the latest technology for road building and maintenance."

But to optimize the segmentation approach, Volvo Construction Equipment has to break down the process of road construction step-by-step to ensure the product portfolio suits the customers' needs exactly.

Heavy infrastructure

Before road construction can begin, the heavy infrastructure sector has to clear a path and provide the materials for the road. "The most efficient way is to be able to obtain the aggregates required for the road from the site clearance itself, or from an area close to the site," explains sales engineer Bengt Morén.

"New road construction generally begins with 'cut and fill', which is the same for any heavy infrastructure project, such as airports, power plants, harbours and ports," he says. "Excavators are needed to remove trees, vegetation and top soil. Often the area will be quite soft, so it is necessary to bore holes along the route and fill them with cement or a mix of cement and crushed limestone to stabilise the ground and make it strong enough to support the road embankment itself and all the traffic. The segmentation focus at this stage concentrates on developing excavators, wheel loaders and articulated haulers required for land clearance and transporting materials for road construction."

Road construction

With its new dedicated business line, Volvo has the full product offering when the actual road building begins, explains Richard Owen, head of road machinery in Europe, as he describes the process: "Once the site clearance is complete, you've got to profile the sub-base - this is the soil that the roads will be built upon. A motor grader is used to take the sub-base to a reasonable level of flatness, as well as profiling the ground. Even at this early stage you may wish to create a slight camber.

"With every stage of road building it's essential to compact each layer, otherwise the finished road will quickly fail," Richard adds. "At this stage a soil compactor - also known as a single drum compactor - is used to compact the soil, and increase its load bearing capacity. This can either be a smooth drum for non-cohesive soils, like sand and gravel, or a padfoot drum with feet for cohesive soil, such as clay or silt."

Specially graded aggregate can then be brought in by articulated haulers - either native material from the site or imported from a quarry - to form the unbound base course.

Getting it right first time

After grading and then compacting the unbound base course, the next stage is to lay the first bituminous base course. This layer is a carefully designed and manufactured mixture of asphalt and aggregate and is put down hot with an asphalt paver. Volvo Construction Equipment's ABG paver range suits the European and Asian preference for relatively slow paving, and uses tamping and vibrating screed technology to produce a high-density asphalt mat. The Blaw-Knox paver meanwhile, typically lays at a higher speed using on (vibration) only screed technology - a method more popular with North American contractors.

"The demands on road contractors for precision are rising all the time - you've got to get it right first time, otherwise the financial consequences can be severe," explains Richard. "If the road profile and thickness are not right at any stage, a road builder will have to compensate with more imported materials or remove expensive materials possibly by milling. The material used in successive layers of the road becomes increasingly expensive. Apart from the cost of the oil-derived bitumen, the asphalt takes a lot of energy to produce and has to remain at high temperatures up to the point of being laid.

"Asphalt is typically put down by a paver at temperatures of around 135oC. The asphalt is brought in from the mixing plant on trucks with specially insulated bodies as the mix is ruined if it falls much below 120oC."

After laying the first bituminous base course layer, a tracked or wheeled paver will put down multiple binder layers, depending on the traffic loads it is designed to carry. The first binder layers are typically 100-150 mm thick. A large tandem roller will follow behind the paver to compact each layer before the final wearing course of about 50mm of asphalt is put down.

Post-paving production

"Our machines involvement doesn't stop when the road is laid," says Richard. "Our compact construction equipment and excavator ranges are ideal for jobs such as installing the safety barriers and lights and completing all the landscaping work. And with roads, no matter how well they have been laid, they will ultimately always need to be maintained."

Now that Volvo Construction Equipment offers a product range that fulfils the road construction customer's needs from start to finish, the segmentation approach will reap the benefit for manufacturer and customer alike, says Richard.

"By understanding the whole process from start to finish through segmentation, we can offer the customer much more than just the pavers and compactors," he says. "We are now offering customers a much broader offering. By attracting new customers from road machinery with our new product range, we are also opening up our traditional product range of construction equipment to a wider customer base."