GIBB has been at the forefront of environmentally friendly projects for many years, developing engineering solutions that make South Africa, and the planet, a better place to live in. When faced with a project that involved replacing and installing kilometers of asphalt paving at the O.R. Tambo International Airport, the engineers at GIBB knew that they had to ensure that they are able to deliver in a cost effective and environmentally friendly manner, and so they did.

Over the past eight years, GIBB has undertaken numerous projects for the Airports Company of South Africa (ACSA), making dramatic improvements to the O.R. Tambo Airport in Johannesburg in particular. However, during the last three years, the nature of the projects started to change when ACSA made a commitment to the “greening” of their operations, and GIBB had to make sure they honour this commitment.

“The commitment to environmentally friendly practice was commended and had an impact on GIBB’s operations at all levels,” says Jannie Grobler, Engineer and Senior Associate at GIBB. “We applied energy saving best practices to all our operations at O.R. Tambo, significantly reducing our carbon footprint.”

GIBB could, by no means, compromise on the quality of the asphalt they had to lay down or replace at O.R. Tambo, especially in the light of the heavy-duty nature of aircraft loadings. The end product had to be a superior, high-quality layer with zero tolerance for non-performance or safety risks.

 “There’s absolutely no room for error during any part of the asphalt reclamation and repaving process,” comments Grobler. “There are people’s lives at stake and to complicate matters just a little, any new products or construction methods were subject to harsh loading conditions, including aircraft wheel loads within just 30 minutes of completion.” To put matters in perspective – one aircraft wheel at 22 ton loading is equivalent (in terms of damage) to 1000 x eight ton truck axles. GIBB really had to showcase their ingenuity and engineering excellence, making sure every aspect of their workmanship had the ability to withstand the test of time, and weight.

The first step in the O.R. Tambo asphalt project was to study international best practice reports from leaders in the field of asphalt paving. These included papers from the Australian Asphalt Pavement Association, the North American Pavement Association and the International Society of Asphalt Pavement.

“After the testing phase of the project was complete, it was discovered that approximately 40% of the milled out old asphalt could be effectively mixed into new products,” adds Grobler. “This reduced the need for new product, as well as saving on the costs, energy and carbon emissions associated with the production of new materials.” No longer would the project require about 100 000 tons of asphalt layers per annum that would result in carbon dioxide emissions estimated at approximately 6 000 tons per annum. The GIBB engineers had found a golden midway to ensure that there is a balance between cost reduction, environmentally friendly production and a world-class  end product.

Another benefit when using the recycled asphalt meant that the dumping of valuable, salvageable and environmentally hazardous asphaltic materials was effectively reduced by 90% and in some cases eliminated altogether. In fact, the recycled asphalt material contributed to a product that was better than new. The use of innovative pavement designs decreased life-cycle costs and material usage of new flexible pavements by 20% to 25%, once again leading to savings in raw materials and heating/fuel carbon dioxide output over the full life-cycle period. This has meant that the new technology will be implemented in pavement rehabilitation and new construction projects worth approximately R1.5 billion over the next 10 years.

“Thanks to GIBB’s contribution, the next decade will see enormous reductions in the use of potentially damaging materials due to a new era of paving,” concludes Grobler. “Because we are so committed to changing people’s lives, Africa’s busiest airport will be able to offer world class service to both business visitors and tourists alike for decades to come.”