Multi-disciplinary contractor, Edwin Construction, is playing a key role in expanding South Africa’s road network as it presses ahead on strategically important projects in the Limpopo and Free State provinces.
Traffic volumes along Route 33 (R33) have steadily increased in intensity and over time the roadway has faithfully carried endless streams of private and commercial traffic. Now however, intensive reconstruction is required to restore and elevate the present riding surfaces along this vital socio-economic corridor, with the Roads Agency Limpopo awarding the contract to Gauteng based Black Economic Empowerment company, Edwin Construction, a 9CE CIDB (Construction Industry Development Board) rated contractor.
This road is currently a main conduit for heavily laden trucks transporting materials for Eskom’s new 4 788 MW Medupi Power Station, which is under development outside the coal mining centre of Lephalale, and Edwin Construction needs to plan around these frequently abnormal road transport movements as it presses ahead on this fast-tracked project. In some areas, and as an interim measure, the construction company has carried out temporary patching to restore failed sections.
Edwin Construction’s scope of works on the R33 is split into two contracts covering a total distance of around 133 km, and entails a complete reconstruction and installation of open earth drains, building up the new road level to sealed base. The new road will be widened to a 4 m lane, with a 0.5 m surface shoulder, and a 2.5 m wide gravel shoulder.
Phase one extends over 32 months and runs from Marble Hall to just short of the town of Modimolle; and the second, 24 month phase, from Modimolle to Vaalwater. Most of the route is relatively flat with the exception of a 12 km section along the way that crosses over the Waterberg escarpment. Construction commenced on the Marble Hall to Modimolle portion in March 2011.
“Below the existing R33 pavement, the material is considered sub-standard,” explains Edwin Construction director, Greg Williams.
“Lifting the existing alignment of the road is therefore the most economical approach.”
Along the R33, the company is using the existing pavement as the foundation, ripping and recompacting this selected layer and then lifting the road with a 300 mm cement stabilised sub-base, and here the company’s recently acquired Cat RM300 rotary mixer is at the heart of the re-construction programme. This RM300 joins a new Cat PF300C pneumatic tyre compactor, which will be used during the slushing stages to prepare the base. Both units were supplied and supported by southern African Caterpillar dealer, Barloworld Equipment, and join a 120 strong plant fleet.
Like the R33 contract, over the past five years all of Edwin Construction’s road projects have involved stabilisation, motivating the company to switch from the use of graders to in-situ recyclers, especially when working below 150 mm.
“We find that a large percentage of the provincial tenders call for the widening and upgrading of existing roads,” adds Williams.
“A number of our clients are now specifying the use of a rotary mixer on these projects. Machines like the Cat RM300 provide a more efficient distribution of the stabilising material, resulting in downstream quality.”
The Cat RM300 takes production to new levels of efficiency on the R33, milling the existing premix layer and stabilising the 300 mm sub-base layers in one continuously advancing operation.
“The results we have achieved have been fantastic. The ability to hydraulically shift the entire cab from side-to-side, for example, really speeds up the work rate as there’s no need to plan in half-widths, plus the mix is always visible from the operator station.”
Cat’s RM300 is designed to work well in both full depth reclamation and soil stabilisation applications and the machine can be set-up either for water or bitumen spraying tasks, depending on the road design requirements.
Expanding on the RM300’s technical features, Barloworld Equipment product manager, Johan Hartman, says the machine has been designed from the ground up for its purpose-built civil engineering application.
“A direct-drive mechanical transmission drives the Cat universal rotor, equipped with 200 point-attack carbide-tipped tools arranged in a chevron pattern for maximum breakout force, with three rotor speeds available for maximum performance in a variety of materials and cutting depths,” explains Hartman. The machine’s maximum rotor depth of 457 mm comfortably caters for a wide range of road reclamation tasks.
In terms of the production sequence on the R33, the Cat RM300 travels upfront, linked-up to and pushing a water tanker ahead of it. Following behind is a 16 t padfoot, then a 12 t smooth roller, with a Cat 140H motor grader fitted with the Trimble system completing final levels. Around 1 000 m³ is being stabilised daily.
The stabilised sub-base on the R33 will be followed by a compacted G1 base specification that specially caters for heavy current and future traffic volumes. Sub-base material is being sourced from calcrete borrow pits in the area, with the G1 supplied from a local quarry in Modimolle. The final riding surface entails a chip and spray (19 mm and 6.7 mm double seal) carried out by a sub-contractor.
Warden revamp, WBHO JV contracts
Edwin Construction’s contract gains continue nationally, with the company enjoying significant growth under the leadership of company founder and engineer, Eddie Maila, who serves as the current chairman and CEO.
Maila’s first entrepreneurial entry as a roads and earthworks contractor commenced in 1997, and now as then, the core business has always been in public sector infrastructure. Overtime, a close association with Johannesburg Stock Exchange listed entity, WBHO Construction, has subsequently led to the latter acquiring a majority interest in Edwin Construction and the two companies frequently work on joint venture (JV) projects.
Milestone contracts in this respect include Eskom’s Ingula Pumped Storage Scheme development near Ladysmith, where Edwin Construction worked as a JV partner for the construction of the Bedford and Braamhoek dams forming part of the Ingula project. Edwin Construction was also responsible for airside and landside stabilisation works at Durban’s new King Shaka International Airport, where it was involved as a JV partner.
Current JV examples include six road contracts in the Free State, as well as a building project for a new taxi rank and related retail development in Thohoyandou, Limpopo province.
Meanwhile, in addition to the R33, Edwin Construction is also deploying a Cat RM300 along a 17 km section of the P16-1, essentially the road from the R103 between Warden and Villiers to Vrede Town. The new design comprises a 3.7 m lane, with a 2.5 m surface shoulder and a 2 m gravel shoulder.
“Here, as on the P16-1, we’re using the RM300 to good effect, milling and stabilising to a depth of 150 mm,” says Williams. Along the route, Edwin Construction’s enterprise development company (ED), KZN Projects, is responsible for the construction of two bridges and two in-situ culverts.
“Going forward we have a strong order book well into 2013 and as in the past, we will continue to serve our traditional markets in provincial roads where our partnership approach has been proven to add value. Here, the adopting of technologies like rotary mixing will continue to refine our competitive edge,” maintains Williams.