In a recent alert issued by the New South Wales (NSW) government’s transport department, concerns have been raised regarding the environmental impact of macro synthetic fibers used in shotcrete and concrete applications. Macro synthetic fibers, commonly employed as reinforcement in infrastructure projects, have been found to dislodge over time, posing a threat to the environment. Notably, a major road project in south-eastern NSW, where shotcrete was reinforced with these fibers, witnessed a significant release of fibers into the surrounding environment, highlighting the urgency of the issue.
The NSW government is taking proactive steps to address the sustainability challenges associated with macro synthetic fibers. Technical Services at Transport for NSW are currently reviewing the suitability of these fibers for outdoor applications, with a forthcoming Technical Direction to guide future practices. Meanwhile, in an effort to minimize the risk of fibers escaping into the environment, immediate measures have been recommended for project sites. These include screeding the surface for a smooth finish, applying a durable cover layer over shotcrete/concrete, and considering the use of steel reinforcement fibers in environmentally sensitive areas.
For those involved in projects that have utilized shotcrete or concrete with macro synthetic fiber reinforcement, a thorough inspection of the material is advised to assess its condition and potential for fiber dislodgment. Additionally, contractors employing macro synthetic fibers in tunnels must identify spoil disposal locations and implement measures to prevent fibers from escaping into the environment. The NSW government’s alert underscores the importance of carefully considering proposals for the use of macro synthetic fibers in shotcrete/concrete within outdoor environments, aligning with the provided guidelines to ensure environmental sustainability.
It’s crucial to note that shotcrete/concrete with macro synthetic fiber reinforcement is susceptible to weather conditions, including the corrosive effects of rainfall and UV exposure. This susceptibility should be taken into account when evaluating the suitability of these materials for outdoor use. Furthermore, end-of-life options for macro synthetic fibers must be carefully considered in any proposed shotcrete/concrete applications to ensure responsible and sustainable practices throughout the lifecycle of infrastructure projects.
The full alert can be found here [pdf].