In October 2019 RSD were hired to supply 12,000m3 of PFA Grout for ground stabilisation and piling preparation at an industrial re-development site in Oxfordshire . RSD were involved from the design stages conducting laboratory trials of the proposed materials at the Grange Quarry facility in Lockerbie.
The product required was an 80:1 PFA:Cement grout which required to flow into an ex maintenance tunnel on the site in order to provide a stable piling environment for future development. The mix therefore had to meet very stringent and consistent high flow rate properties while balancing this with the requirement for a very tight tolerance on load strength.
The high flow requirement and small particulate size of the raw materials provided some challenges for normal flow through the concrete plant. RSD solved these problems during the mix development stage by using live testing of the laboratory trailed mixes. The introduction of additional vibrators and liners within the plant hoppers proved to be the ideal solution. There was also a requirement for the mix to be pumped from plant location into the works. This requirement was addressed by the introduction of a static mixer located immediately under the plant. The mixer served as a loading hopper and balance tank to ensure continuous supply on each pour.
Once on site it was found through compressive strength testing that the required strength could be maintained with a higher ratio of cement to PFA enabling reduction of cement contents and consequent savings through the project.
Cubes were made on site and were delivered weekly to Grange Quarrie’s laboratory in Lockerbie. Compressive strength results were issued to the client by laboratory staff on a weekly basis and records maintained for future scrutiny. Analysis of results was carried out by Dascon Consulting in order to ensure that the tight compressive strength tolerance was adhered to throughout the process.
The contract was completed on schedule without any problems relating to supply or quality.
This project is another example of the service RSD can provide through established relationships with other industry professionals, and the additional resources and pre contract support that we can provide.
On the logistics side the plant arrived on site in November 2019 and work was completed on schedule in February 2020. On completion of the contract plant was disassembled, removed from site and relocated for a short maintenance period before its next job supplying Crossdykes Windfarm in Dumfries and Galloway. RSD’s ability to turn plant around quickly in this way provides maximum service, maximum efficiency and minimum disruption for our clients
Below you can see pictures and video showing preparatory work, the site, and supply.