Possibly our largest sprayed concrete piling contract of the year took two of our crews to Chesham in Buckinghamshire for works to be completed in two distinct phases.

Sprayed concrete overlay and infilling from the capping beam down five metres was the first phase before bracing and subsequent excavation for the remaining five metres was the agreed programme of works.

All fairly standard methodology for this type of application, but the two phases of works had to be completed at the end of 2023 and the beginning of 2024 so the weather and low temperatures were against us, unless the weather was kind, and it was not.
Low day time temperatures, and even lower night time temperatures conspired to make the application of ready mixed shotcrete problematic, combined with continuous heavy rainfall and short daylight hours.

Works had to be phased to allow continuity, so anything not temperature dependant such as steel fixing, fixing of a cavity drain system and protection works were all done during these adverse weather conditions. The ‘good days’ were reserved for the shotcrete operation, but were still reliant on a good delivery schedule from the shotcrete material suppliers. A heavy reliance was also placed on the Met office to forecast suitable weather.

The use of an accelerator in the shotcrete mix was also beneficial in achieving a fast initial set of the concrete before lower temperatures could have an effect on the setting time, and possibly compromise initial and final set strength under testing.

All works were completed within programme despite going down to the very last scheduled day. Subsequent concrete testing at 14.00 and 28.00 days proved the sprayed concrete infill and overlay to be well within the required specification.