Civil Engineering September 2021 | Vol 29 No 8

Transport eng i neer i ng E arly concrete roads were laid using obsolete techniques and equipment. Modern designs, new construction methods, better surface finishing, and high-tech machinery mean that it is now possible to produce high- quality concrete pavement surfaces that satisfy the needs and objectives of road users, neighbouring communities, and road managers. Concrete pavements offer substantial environmental, economic, and social benefits and should be more widely re- garded as the sustainable solution to South Africa’s road network. These roads, which undoubtedly offer lower whole-life cost for comparable design, are the natural choice for projects where performance, value, longevity, social responsibility and concern for the environment are paramount. Furthermore, concrete pavements offer a long service life that normally exceeds 30 years and require relatively little maintenance and repair to produce long-term savings in raw materials, trans- port and energy. The reduction in traffic delays caused by roadworks on concrete pavements also cuts fuel consumption and exhaust gas emissions. In fact, at a time of soaring petrol prices, fuel saving for cars and goods vehicles is an important advantage of concrete roads that is not always apparent or published. Yet the facts testify to such cost savings. NOTABLE FUEL SAVINGS The National Research Council of Canada, for example, carried out a series of investigations which focused on various types of pavements and vehicles in different seasons of the year. Reduced fuel consumption by heavy trucks was observed in all phases for concrete pave- ment roads compared to asphalt roads. The studies found that fuel saving on concrete pavements for empty and full tractor-trailer units ranged from 0.8% to 3.9% in four to five periods in the year, based on 95% reliable survey results. This means an average fuel saving of 2.35%, which is certainly not negligible and would represent an immense difference in overall fuel consumption (as well as greenhouse gas emissions) over the life- time of a busy freeway. Secondly, the Transport Research Laboratory in Britain carried out research to determine the effect of the rigidity of pavements on fuel consumption. Here the reduced reflection of concrete roads resulted in a 5.7% reduction in rolling resistance, also providing noteworthy fuel savings. Similar fuel economy results have been obtained from extensive research done in Sweden, Japan, and the American states of Texas and Massachusetts. Apart from the type of pavement, the evenness and surface texture of the road surfaces are important factors influencing fuel consumption. That is why the quality of the finished concrete surface plays such a crucial role. ADVANTAGES AND BENEFITS Sustainable concrete pavements make efficient use of natural resources and respect the environment throughout life cycles. The roads provide services to society in terms of mobility, safety and comfort by means of judicious choices Modern concrete roads offer extensive and diverse benefits Bryan Perrie Pr Eng CEO Cement and Concrete South Africa bryan.perrie@cemcon -sa.org.za Today’s concrete roads are a far cry from the concrete pavements of old which are still in existence but were designed long ago to very different design criteria than those employed currently. 18 September 2021 Civil Engineering A completed concrete road A CRCP BRT lane in Cape Town