CORE REINFORCEMENT Maccaferri’s geogrids can improve asphalt life and reduce asphalt thickness
Engineering solutions provider Maccaferri will highlight the cost benefits of its wide geosynthetics range of Geogrid products at this year’s Conference on Asphalt Pavements for Southern Africa (Capsa), as well as significantly increase its presence in the road infrastructure and construction sectors for the company’s key business focus areas.
Capsa will be held at Sun City, in the North West, from August 16 to 19.
“With the significant focus on roads in South Africa – and particularly in Africa – geosynthetic solutions are suited to the African environment, providing the best performance using Maccaferri reinforcement solutions,” says Maccaferri geosynthetics business manager Edoardo Zannoni.
The geosynthetics for asphalt reinforcement solutions can help manage challenges such as “reflective cracking, thermal and fatigue cracking, rutting and shoving, haunching failure and high axle loads. Further, geosynthetics for ground stabilisation solutions can assist in construction on peat soils, differential settlement and weak subgrades, as well as reduced construction layer thickness”, says the company.
Zannoni stresses that the key features of the MacGrid AR range are focused on improving the asphalt life threefold while reducing the thickness of the asphalt. “Consequently, this reduces the overall cost of the pavement, as less materials are required or the life of the pavement is increased, reducing the maintenance programme. “Therefore, it also reduces the carbon footprint as hauling, construction and time on site are reduced,” he adds.
MacGrid AR, which is currently applied in local road rehabilitation projects and will be showcased at Capsa, is one of the flagship products of the company’s pavement solutions offering.
“MacGrid AR is a planar geo- grid structure used for asphalt reinforcement in road construction. The structures are made from glass fibre, which is woven in a grid configuration and then coated in bitumen,” he explains.
In addition to high tensile strength and a high modulus of elasticity at low elongation, the geogrids “offer a cost-effective solution for preventing reflective cracking within the upper asphalt layers of road pavements during resurfacing works”, according to Maccaferri.
MacGrid AR products are produced with either an adhesive or a geotextile backing, which act as moisture-barrier systems.
Maccaferri last month applied MacGrid AR 10A.7 to the 10 000 m2 Stapleton road resurfacing project, in Pinetown, Durban. Maintenance is beginning throughout South Africa’s roads network, adding to the extensive project work MacGrid AR has been responsible for in Africa – in Uganda, Mozambique, Nigeria and Egypt, for instance.
Maccaferri has applied more than two-million square metres of MacGrid AR in 2015 and it is forecast to double this figure by the end of the year.
Meanwhile, Zannoni acknowledges increased product awareness from the road construction and rehabilitation industry, but points out that there are still challenges, such as industry’s conservativeness and marginal knowledge of the product and solution. Nevertheless, Zannoni believes that once industry experiences the benefits of the solutions, it will become a stable solution for roads authorities.
Other geosynthetics solutions that will be exhibited at Capsa include MacGrid EG, which is used in the reinforcement of subbases. MacGrid EG is a high-modulus, high-density polyethylene grid used within the granular layers of road construction, which provides a soil stabilisation function.
Meanwhile, Mactex W1 poly- propylene woven geotextiles are used for general soil and ground stabilisation applications, where separation and reinforcement functions of subgrades and sub-bases might be required. Zannoni points out that, in traditional rock pioneer layers in road construction, rocks sink into soft ground until a stable platform is created.
However, Mactex W1 prevents the rocks from sinking into soft ground, which reduces the volume required, says Zannoni, emphasising that the company considers various solutions for all pavement structures, depending on the cost-benefit analysis, keeping in mind construction restriction and time.
Additionally, Maccaferri uses in-house design software, comprising several design methods, to calculate the benefit of reinforcement and the required thickness of the pavement layers, which are available to the public and supported by in-house training.
The company further aims to highlight the applications to which MacGrid AR and Geosynthetics products can be applied at Capsa and to subsequently improve the cost benefit of traditional technologies, such as deep box- cutting.
Using these solutions can reduce pavement thickness, which sub- sequently reduces the thickness of the rehabilitation, says Zannoni, adding that this is particularly beneficial when there are servitudes, such as communication or electricity cables running underneath the pavement, as the pavement will be shallower.
“Nevertheless, the design life of the pavement will increase, keeping the same layer thicknesses with a reduction in costs,” concludes Zannoni.