Caterpillar 14M motor graders equipped with AccuGrade dual GPS systems with cross-slope capability are being used for road construction and refurbishment in the Republic of Burundi.

The two graders are working with an AccuGrade-ready D7R Series II track-type tractor (dozer) meaning performance and productivity is boosted on the road projects by sharing the machine control systems, Caterpillar stated.

These are the first AccuGrade systems being used by the contractor Sogea-Satom to replace traditional surveying and staking methods on its earthmoving projects.

A spokesman for Caterpillar said, "While the initial requirement was to equip both 14M motor grades with AccuGrade dual GPS systems, the ability to also have a track-type tractor with guidance was reckoned to offer significant benefits with earthmoving activity ahead of road formation."

The system is being trialled on three Burundi road projects including the 35 km RN14 Kirundo-Gaseyni trunk road, the 104 km RN12 Gitega-Muyinga trunk road and 31 km of road and pavement refurbishment in the capital, Bujumbura.

The longest section of road is the RN12 which runs through a mountainous region some 1500 to 1600 m above sea level and is heavily shadowed by trees and vegetation that could, in some areas, mask satellite signals for AccuGrade.

"Despite this, Sogea-Satom reports that after 12 months of using the systems on-site, AccuGrade has given +/- 1 cm accuracy when the road formation is surveyed," the Cat spokesman added.

Sogea-Satom first used AccuGrade with the D7R to remove 30 cm of poor material to allow for foundation and road base materials to be installed.

Previously, this requirement was met using an excavator and one truck, with productivity at just 100 m a day. Up to 50 cm of material was also frequently being unnecessarily removed, Caterpillar said. Using the D7R with AccuGrade, 100 m of road was completed in 30 minutes, vastly improving productivity, the company added.

"By using the 14M motor graders, the quality of work has been dramatically improved too, compared to relying on stakes every 25 m.

"On-site surveyors now have more time for data preparation and grade checking, and they have been reporting improved quality and earlier completion at different stages of road building," the Caterpillar spokesman said.