The old Mangere Bridge was replaced during the 1980’s with a newer bridge, which had subsequently become overloaded with increased traffic flow.
The MHX Alliance which included Fletcher Construction, were contracted to duplicate the newer bridge, adding another four lanes to cope with the current and expected traffic volumes.
During construction, specific areas of the topping slab were found to have minimal cover and due to concerns for steel durability in a marine environment, Xypex Concentrate was selected as the preferred option to provide waterproofing and steel protection, prior to the hotmix road surface being overlaid.
Where time frames were very tight, Xypex Concentrate was overlaid with Xypex Megamix II high build repair mortar. This enabled the hotmix to be laid shortly afterwards without compromising the Xypex Concentrate.
To optimise chemical transfer, Xypex Gamma Cure was used as a pre-wetting agent, immediately prior to Xypex Concentrate being applied by broom, followed by a mist of water and a mist of Gamma Cure to prevent premature drying of the Xypex Concentrate coating.