Fibre Reinforced Concrete Paving

BarChip fibre reinforced concrete was used to eliminate corrosion risks and reduce construction costs of the Wonthaggi and Inverloch sludge drying pans.

In 2015 SGW undertook construction of two new sludge drying pans for their water treatment plants in Wonthaggi and Inverloch. The project aim was to provide long term, effective facilities to dewater lagoon sludge, thereby eliminating the need to take lagoons offline for major desludging processes.

Due to the corrosive environment in sludge drying pans, the original design called for stainless and galvanised steel reinforcement, making the potential build cost very expensive. BarChip proposed an alternative design that replaced steel reinforcement with 4 kg/m³ of BarChip 48 macro synthetic fibre. The design was validated by JKP Static and accepted by the project team. This new design was far more cost effective and added much needed durability to the structure.

Due to the shape of the drying beds, concrete had to be hand placed on 4:1 batter slopes. This required very low concrete slump for the concrete to stand up on the hill and not flow down. The dry slump meant that concrete pumping would be a slow and difficult process. To overcome this, the concrete was placed onto the batter slopes using excavators. The “floor” of the pan was placed using a laser screed to obtain the very strict margins required for the slope of the floor.

Lagoon desludging operations have now been underway for six years, with sludge “pumped” onto the slabs for drying through air evaporation until ready for transport for stockpiling and reuse. During this time, the BarChip fibre reinforced concrete has met all expectations from the project stakeholders.