FITT Resources recently completed a series of repair works on the Mangrove Creek Dam on Central Coast NSW.
The scope of works, which were completed between October 2019 and April 2020, included a series of joint repairs on the spillway chute wall, along with repairs to the slab floor, plus concrete repairs to cracks in the spillway wall, the dam face joint, and the interface between the dam wall and the toe slab.
Spillway wall joint repair
This part of the project involved replacing the joint filler on all vertical movement joints in the eastern and western walls of the spillway.
Water and grit blasting were used to remove existing materials, and closed cell foam was then push fitted back into the joints. This was followed by application of Parchem Emer Seal 200 sealant.
Joints were located at various heights in the spillway:
- 6 joints at approximately 10 metres
- 20 joints at approximately 6 metres
- 6 joints at approximately 3.8 metres
Spillway Chute Floor Slab Repair
The work was required to be carried out using a projected engineered work platform. There were four joints of varying lengths (average 4 Lm per joint), and concrete cutting 1 metre either side of the joint was required, up to an average depth of 125 mm.
Corroded reinforcement bars when then exposed and treated with an anti-corrosive coating, and SL81 mesh and anchor bars were then installed.
This was followed by 5mm aggregate concrete being poured up to the level of the slab.
Other Concrete Repairs
Further concrete repairs carried out as part of the project included cracks in the spillway wall, as well as to the dam face joint, and the interface between the dam wall and toe slab.