One of the casualties of the heavy rainfall of the past year has been causeway retaining walls between the Springs Branch of the Leeds & Liverpool canal and Eller Beck, a river near historic Skipton Castle in North Yorkshire.
Sections of the walls collapsed due to erosion and British Waterways, responsible for the maintenance of the walls, called in Dew Construction of Oldham, Greater Manchester, to put them back up again.
The project involved grouting the existing structure to provide added strength, rebuilding the collapsed section and repointing the wall.
Because of marked fluctuations of water levels in the river, especially the rising of the river after the frequent rainfalls, a quick setting mortar capable of providing early high strength was essential for repointing the lower courses of stonework.
The solution came from Easipoint in Chorley, Lancashire, and their Marine Mortar, a gun-injected mortar containing anti-washout additives.
Specialist sub-contractors Leighstone of Leigh, Lancashire, were employed to carry out the work. They used the Marine Mortar on the lower parts of the wall rising from the riverbed and Easipoint Standard Mortar higher up where it was not in danger of being washed out. In all, more than 500m2 of stonework was repointed as part of the contract.
Typically, Easipoint Marine mortar achieves an initial set in 45 minutes and attains a compressive strength of 11N/mm2 after three days, rising to 31n/mm2 at 28 days. The anti-washout, quick-setting formulation allows the mortar to be used between tides in coastal areas, for example.