AECI SprayPave is now able to offer the asphalt industry scarce 10/20 penetration grade bitumen using unique technology that enables the production of specialist bitumen products. AECI SprayPave manufactures bituminous binders, emulsions, primes and pre-coats for road construction. In response to an ongoing bitumen shortage in South Africa, the company acquired a multistage bitumen converter from Technix Industries in New Zealand in 2015, only the second to be commissioned worldwide. The technology enables AECI SprayPave to achieve predictable and repeatable conversion of penetration grade bitumen available from South African refineries to grades that are both lower in penetration and higher in softening point than the feedstock bitumen. “We are very excited to be able to add 10/20 bitumen, which is currently in short supply, to our offering,” says AECI SprayPave director Eddie Jansen van Vuuren. “The 10/20 bitumen product conforms to the penetration grade bitumen specification.” 10/20 bitumen is commonly used in the production of high modulus asphalt (EME), which is well suited to high trafficked roads likely to suffer significant fatigue and stress. Currently this grade of bitumen is only supplied by one South African refinery. Other local refineries have not been able to produce 10/20 bitumen due to higher demand for other “normal” grades and difficulty in meeting the required specifications. Unforeseen breakdowns and scheduled shutdowns at refineries add to the problem, Jonathan Bell, AECI SprayPave’s Cape Town technical manager, points out. The multistage bitumen converter uses pressure, heat and air to precisely convert bituminous refinery feedstocks into high grade bitumen. The softness, penetration index and physical properties of the bitumen can be changed to meet exact design specifications. The controlled processes in a bitumen converter make it possible to rearrange chemical structures to create asphaltenes. The gentle process and highly efficient addition of air and therefore oxygen (air rectification), preserve the highly polar aromatic/resin fraction and minimise coke build-up. In addition to the 10/20 product, the current bitumen line-up offered by AECI SprayPave includes 70/100, 50/70 and 35/50. “The converter has enabled us to deliver SABS certified 50/70 bitumen to the Western Cape since it became fully operational three years ago, with steady expansion of the product range since,” explains Bell. “The value of this technology to the local asphalt sector was highlighted when only soft grade bitumen was available locally and the converter was able to overcome this shortfall through successful production of 50/70,” he says. “Our technical relationship with the plant manufacturer, Technix Industries, remains strong with a high level of collaboration to deliver value to Southern African customers.” Bell says throughputs of 30 to 60 tons per day can be achieved when converting from conventional 70/100 to 10/20. Herman Marais, technical director at AECI Much Asphalt, AECI SprayPave’s parent company, adds that demand for high modulus asphalt incorporating 10/20 penetration grade bitumen is growing in South Africa. “The technology is proving valuable for high traffic load routes. Demand is anticipated to increase exponentially when the major N3 freeway contracts are awarded, as several of these projects will use high modulus asphalt.” Jonathan Bell, Cape Town technical manager (left), and Eddie Jansen van Vuuren, director at AECI SprayPave, with the multistage bitumen converter that enables the production of 10/20 penetration grade bitumen.

Fine dust particles not only affect workspaces and equipment in industries like construction, mining and manufacturing, but they also threaten the health and safety of workers, drivers, pedestrians, and neighbouring communities. Dust particles 10 microns in size, known as respirable dust, are not visible to the naked eye and can cause serious harm by penetrating the lungs. Dust particles of 100 microns which are visible and known as inhalable dust, can also lodge in the respiratory tract. Black lung, shortness of breath and respiratory failure are some of the irreversible health effects of ongoing exposure. Driving or operating equipment in dusty environments is also dangerous due to limited visibility. Dust suppression is achieved through the application of a liquid to prevent inhalable and respirable dust particles from becoming airborne. This generally involves a fine spray application of surface-active ingredients dissolved in water that bond to the airborne particles, weighting them to the ground. New Solution AECI SprayPave, a leading manufacturer, supplier and applicator of bituminous binders, emulsions, primes and pre-coats to the road construction industry, has used its expertise in the bitumen field to formulate a waterproof binder known as Dustasolve-10. The product comprises a bitumen emulsion combined with nanotechnology additives. “Dustasolve-10 is designed to target dust on gravel roads, quarries and mines without the need for complicated layerworks equipment,” says AECI SprayPave director Eddie Jansen van Vuuren, pointing out that simplicity of application is key to the success of this product. “Dustasolve-10 can be applied with a bitumen distributor without the need for a roller. In typical warm South African conditions with base temperatures of 25°C and rising, a road can be opened to traffic as little as one hour after application.” How it works Bitumen emulsion comprises varying volume fractions of bitumen droplets dispersed through an aqueous solution with the aid of an emulsifying surfactant. Bitumen emulsions can be easily applied at room temperature without heating equipment. However, Jansen van Vuuren warns that there are some shortcomings to be aware of when it comes to dust suppression solutions. If the bitumen fraction is too high in the emulsion it forms a layer that can sometimes become tacky, leading to lifting or movement under traffic. Another concern is stability of the treated area in wet climates when bitumen emulsion surface treatments that do not bond with the soil are washed away by rain. AECI SprayPave has addressed these concerns by incorporating bitumen additives with properties that enable the Dustasolve-10 particles to bond with the soil particles even at low bitumen volume fractions. This both reduces the inhalable and respirable dust particles rising from unpaved roads and provides a strong waterproofing effect that mitigates water damage to the road surface. Spray applications can be between 1l/m2 and 3l/m2 depending on the surface conditions. Maintenance of the area may require reduced product application rates while achieving further dust control and improving road strength and protection. Depending on traffic on the surface, a maintenance spray may be required one to two weeks after the initial application. Dustasolve-10 has undergone trials at a mine in Limpopo Province and at three sites of AECI Spraypave’s parent company, AECI Much Asphalt, in Benoni and Eikenhof, Gauteng, and Pietermaritzburg, KwaZulu-Natal. The trials have demonstrated the suitability of the product for dust suppression and helped to determine optimum application rates and respray maintenance requirements in different conditions. Jansen van Vuuren says trials to date have shown the new formulation to be quick penetrating, fast drying, non-tacky, waterproof, easy to apply, and competitive in price. Trial application in progress on access road at a Limpopo mine.

AECI Much Asphalt is Southern Africa’s largest commercial asphalt producer. The sustainability of the South African asphalt industry and of the communities where the firm runs its 14 plants is critical to its growth and success. The firm’s flagship plant and biggest employer is in Benoni. AECI Much recognises unemployment and a scarcity of skills as major threats to the future of its business and has used creative thinking to build a loyal, productive workforce and to ensure that small enterprises using its products have the skills to succeed. Looking for solutions to its diverse employment requirements in environments characterised by massive youth unemployment, AECI Much partnered with Harambee Youth Employment Accelerator, a not-for-profit social enterprise that brings business together with young people seeking work. That was five years ago and has been a win-win for the company, the community and the individual, says Ayesha Isaacs, Group Human Capital Manager at AECI Much Asphalt. “We know how hard it is to find employment, especially if you don’t have any form of work experience,’’ says Isaacs. “We see this as an opportunity to recruit fresh talent, to build raw candidates with potential into our requirements and our culture.” She estimates that some 60 job seekers from matriculants to graduates have entered AECI Much Asphalt via this source over the years. “We employ a candidate on a six-month contract. He or she spends two months at the weighbridge (where asphalt is weighed prior to dispatch), two months in the laboratory (where product testing and development take place), and two months on the asphalt plant,” Isaacs explains. “This way we find where the candidate shows the most potential. Those who are the best fit are offered full time employment, while the remaining candidates complete the fixed-term contract with six months of paid training.” She says this arrangement not only reduces the risk to AECI Much Asphalt, but also gives all candidates a better chance of future employment through six months of intensive practical training to develop skills that will hold them in good stead moving forward. “Much is known for producing good calibre employees.” AECI Much Asphalt has recruited 16 full time employees via this platform, several of them working in its Gauteng Regional Laboratory in Benoni. The firm also offers internships for students required to do in-service training as part of their qualifications as well as internal learnerships for employees. Free technical skills for SMMEs In another initiative that helps to build competence within the roads sector, AECI Much Asphalt offers free workshops to customers such as SMMEs and government departments that use asphalt for small projects. “We launched this initiative 15 years ago to promote sustainable asphalt paving on South Africa’s roads and help emerging contractors grow their businesses,” says managing director Bennie Greyling. “By sharing skills on how to use our products properly we hope to provide employment opportunities in the construction sector and at the same time to broaden our client base.” The Best Practice Workshop on Hand Laid Hot Mix Asphalt provides practical instruction on techniques for the placement of hot mix asphalt by hand on small projects. Each delegate receives a manual on the selection, use and application of AECI Much Asphalt’s products and a certificate. Many hundreds of individuals have received the training across South Africa since the workshops were launched in 2006. “At the end of the day, AECI Much Asphalt and the contractor who is placing our product have a joint responsibility for its quality,” says Greyling. “We need to work together for the best outcomes.” AECI Much Asphalt employees recruited through Harambee Youth Employment Accelerator (from left): Benevolence Sithole and Petunia Mbatha, Lab Technicians at the Gauteng Regional Laboratory in Benoni; Velaphi Thubane, Plant Technician at the Benoni Plant; Gamane Madonsela, Lab Technician at the Benoni Laboratory; and Mmoick Matsie, Senior Lab Technician at the Gauteng Regional Laboratory.