The location

Copper mining is reported to have begun in the Avoca River valley in 1720 and continued, intermittently, until 1982. Consistent mineral extraction has left an environmental legacy that comprises of open pits, shafts, spoil piles and former mining buildings.

The project

During health and safety works that were being carried out by Civil and Environmental Engineering Contractor, Priority Construction Ltd., it was identified that the former mining site was impacting the quality of the water in the Avoca River. Water dischargers from abandoned copper and sulphur mines were acidic and metal laden, contaminating the nearby river water.

It was decided that the spoil areas would need to regraded and capped, with drainage channels to redirect upstream drainage around the site, instead of through it. Whilst the original design used a combination of precast concrete channels and HDPE liner, there were concerns around the long lead in times for the precast concrete and the construction risks associated with steep slopes. Instead, Priority Construction Ltd. proposed the use of Concrete Canvas.

The solution

At Concrete Canvas, we offer Geosynthetic Cementitious Composite Mats (GCCMs), which are an alternative to traditional concrete methods. Unlike most concretes, our GCCM uses a specialist high early strength concrete, with a limited alkaline reserve. This means it has a very low wash out rate and can be directly discharged into the water course, without the need for prior treatment, making it an ideal solution for channel lining.

For this project, we recommended the use of CC13, which is our thickest type of GCCM. However, before the installation process could begin, the channel needed to be excavated and compacted to profile. A 250mm x 250mm anchor trench was then built on either side of the channel to allow the leading edge of the GCCM to be buried, preventing any undermining. Once the channel was prepared, the CC13 was mounted onto a spreader beam and hung from an excavator, allowing it to be easily unrolled. Each piece of CC13 was cut to a specific profile length and dragged into place, minimising material waste.

Priority Construction Ltd. installed the CC13 transversely to accommodate for change in the channel profile, with layers overlapping by 100m in the direction of the water flow. The overlaps were then sealed using Everbuild Clearfix adhesive sealant and screwed together using stainless steel screws. As an extra precaution against undermining, 250mm steel ground pegs were also inserted into each overlap in the anchor trenches and then backfilled with material.

As the channel was located on a steep hill, concrete steps were installed to dissipate the water energy. Due to the flexibility of CC13, it was able to be laid over each step and pinned into the vertical interface of the steps using Hilti anchors. After each day of work, the CC material was hydrated using a hose and a 6000ltr water carrier.

The results

In total, 1,520m² of CC13 was installed within two weeks, providing long-term scour protection and erosion control for the network of drainage channels on the site. Despite the steep and varying slopes, we achieved installation rates of over 200m² per day.

Following the success of this installation, Concrete Canvas is now being considered for multiple projects in the same region, in both the public and private sectors.

“After carrying out some research into alternatives for in-situ or precast concrete drainage channel we encountered Concrete Canvas. As we learned more about this solution we realised it would be ideal for the Avoca Mines Remediation Project which we had been awarded. We succeeded  in gaining approval from the client for the use of Concrete Canvas. As the project progressed it became clear that this solution provided a number of benefits when compared with traditional methods. These benefits included speed of installation and flexibility in terms of levels e.g. where there were changes in design levels. I intend to use this product on future projects where possible.”

Ken Madden – Senior Contracts Manager, Priority Construction Ltd.

Contact Concrete Canvas for Channel Lining

If you are looking for a flexible and durable concrete solution for your channel lining project, get in touch with Concrete Canvas. We can assess your project requirements to match you with the most suitable type of GCCM. With no need for plant or mixing equipment, we can even guide you through the installation process: simply unroll, secure and add water.

The post Concrete Canvas Channel Lining at Avoca Mines appeared first on Concrete Canvas By Daeng Group.

The project

The Five Mile Lane Improvements Project aimed to improve safety along the existing A4226 road (also known as Five Mile Lane) in Barry, South Wales. The scheme involved a combination of improvements including construction of a new road that bypasses the winding central station of the existing road.

The solution

CC was delivered in bulk rolls of the specified 8mm variant (CC8) and mounted onto a spreader beam for easy deployment. The material was laid transversely across the width of the channel, starting downstream to allow for the creation of material overlaps in the direction of water flow to prevent ingress.

Given the volume and flow rates anticipated, the channel required lining to prevent water ingress into the cutting and scouring of the invert.

The material was cut to length on site to reduce material wastage and accommodate variations in profile width or channel curvature. Each transverse layer was secured within the anchor trench using 250mm ground pegs through the overlapped layers. The material was then also jointed along the overlaps at 150mm intervals using 30mm stainless steel screws, placed 30mm away from the leading edge.

Following jointing and fixing, the CC was hydrated using a 4000-litre bowser and pump. CC reaches 80% strength just 24 hours after hydration, after which time, the anchor trenches were backfilled to bury the material edges, providing a neat termination and preventing any water ingress.

Once set, CC forms a thin, durable, water proof and fibre reinforced concrete layer, providing 7.5x greater abrasion resistance than a poured OPC alternative.

Concrete Canvas® is the original GCCM and the first product to declare conformance to ASTM D8364-Standard Specification. This is the only internationally recognised GCCM specification standard and lists erosion control applications by three classifications, Type I, Type II and Type III. It defines the minimum performance values required for each type based on the use of test methods that are specific to GCCM materials. ASTM D8364 is an important resource for clients, consultants and contractors wishing to ensure the GCCM used on their project is fit for purpose. For Five Mile Lane, we recommended that CC8 which is Type II was used.

The results

Over 2250m² of CC8 material was installed in less than four days by a crew of 4, using minimal plant. As Concrete Canvas has been approved by BBA to provide durability of 120 years, we expect the relined channel to continue protecting the surrounding environment for many years to come.

Contact Concrete Canvas for Channel Lining

If you are looking for a flexible and durable concrete solution for your channel lining project, get in touch with us. We can assess your project requirements to match you with the most suitable type of GCCM. With no need for plant or mixing equipment, we can even guide you through the installation process: simply unroll, secure and add water.

The post Concrete Canvas Channel Lining at Five Mile Lane appeared first on Concrete Canvas By Daeng Group.