Construction World January 2018

ROADS & BRIDGES

Solutions for road construction and maintenance Fibertex geosynthetic solutions for road construction and maintenance includes Fibertex AM-2, a flexible needle punched pre-compressed nonwoven fabric, with added thermal bonding on one side. This product, which is highly durable and resistant to all natural soil alkalis and acids, is used to avoid reflective cracking of new asphalt and to protect subsoil from water intrusion and thereby loss of bearing capacity.

propagation of stress cracks from lower surface layers (older asphalt or chip seal layers) in the case of a road re-seal. “Additionally, when using Fibertex F-grade geotextiles in a separation application below the layer works of the road prism, the road design can be altered to include less of the costly imported engineered fill. This reduces the thickness of the selected layers, resulting in a more cost effective design. Without the use of a separation fabric in weak subgrade conditions, intermixing of engineered aggregate into the weak subgrade could occur. As a result, the bearing capacity of the base course is reduced, which could lead to base course failure of the road. “Fibertex UV stabilised virgin PP geotextiles are the only nonwoven geotextiles produced in Africa with certification for durability of over 100 years, in accordance with the latest EN standards.” By using virgin PP Fibertex AM-2 in road construction and maintenance projects, substantial infrastructural cost reductions are achieved. Virgin PP geotextiles, with a high level of chemical stability under a wide range of environmental conditions, have advantages in installations where the cost of failure may be extreme, in both financial and environmental terms. The Fibertex AM-2 system can be applied mechanically for large volume installations, as well as manually in cases where narrow width installations are required. Fibertex South Africa’s team of experts from branches in KwaZulu-Natal, Gauteng and the Western Cape offer a technical advisory and support service, to ensure correct specification of durable and safe materials for every project. This range of environmentally-friendly geosynthetic materials encompasses nonwoven and woven geotextiles, gabions and mattresses, drainage pipes and fittings and erosion control and cellular confinement solutions. The company also supplies soil reinforcing products, including geogrids and geocells, as well as geosynthetic clay liners and geomembranes as part of composite lining systems used in modern landfills and for other environmental protection applications. 

“The purpose of this pre-compressed polypropylene (PP) bitumen-saturated paving fabric, is to prevent the ingress of surface water into the selected layers of the road prism, reducing the bearing capacity of these layers,” says Chris Powell, Fibertex South Africa – manufacturers of geosynthetic products. “This membrane also act as a Stress Absorbing Membrane Interlayer (SAMI) to prevent surface stress cracking by absorbing stresses imposed by differential loads. Fibertex AM-2 also prevents the

→ priority area for Concor Infrastructure. With over 600 people working on the project, it is an important job creator in the area

– with a high proportion of local residents being employed and trained in semi-skilled roles. There is also a considerable amount

of work sub-contracted to local operators, who in turn also employ local labour. “Beyond the direct and indirect job creation impact, we also see the importance of sharing information about ourselves and the broader industry with local communities – especially young people who may consider a career in construction and engineering,” says Pearce. “For this reason, we recently sponsored and participated in a career expo in the nearby town of eSikhawini; aimed at Grade 11, 12 and post-matric learners. The event helped participants think about their school subject choices as well as career options and possibilities.” The event was organised by Isethembiso Youth Development and was attended by around 300 learners; Concor Infrastructure training manager Lucas Bornman was among the speakers, joining a number of well-placed experts from the University of Zululand, and Science Foundation and the Department of Social Development. 

One of the major culverts constructed.

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CONSTRUCTION WORLD JANUARY 2018