Rapid strength grout for coastal defence scheme

THE CHALLENGE

The Central Rhyl Coastal Defence Scheme is a £69M flood protection project to replace and upgrade more than 600m of sea walls protecting the coastal town of Rhyl in North Wales. The existing sea defences had been overtopped in recent years causing widespread and prolonged flooding. This included major storms in December 2013 when around 400 homes were evacuated after waves breached sea defences at Splash Point. The project would include construction of new concrete stepped revetments and wave wall along with a raised and widened promenade and improved access to the beach via steps and a ramp.

THE SOLUTION

A high performance grout was required for grouting of precast concrete stairs as part of sea defence structure. The grout needed to be very strong and fast setting as it was being used in a tidal zone. After discussions with the main contractor, Pozament Platinum Rapid precision grout was recommended for the scheme. It is a fast setting, shrink compensated precision grout with an initial set time of just 10 minutes and full set 15 minutes. It achieves rapid early strength gain of 12 N/mm² in just 60 minutes, 25 N/mm² after 120 minutes and 40 N/mm² after 1 day. This would allow work to be completed within a narrow time window.

RESULTS AND BENEFITS

The product performed well on site, enabling rapid completion of the grouting in line with the build programme. The shrink compensated formula and slight positive expansion during curing enabled gaps between the precast steps to be fully filled and sealed. Rapid set times and early strength gain minimised the risk of early wash out and ensured the grout stayed in place until it was fully cured. Pozament supplied grout to the site as required by the contractor and ensured consistency of the grout and compliance with specification. When finished the Rhyl Coastal Defence Scheme project will protect more than 500 homes and 44 other properties at risk of flooding.