Two-day concrete pour for Mersey Gateway pylons
Fifty hours of continuous pouring gets construction of new river crossing under way
CONSTRUCTION of the south and north pylons of the Mersey Gateway has commenced with two major continuous concrete pours, each lasting more than 24 hours. The Mersey Gateway, which is being delivered by the Merseylink consortium, is a new six-lane toll bridge being built over the river Mersey. Construction of the bridge requires three pylons to be erected out of the river bed.
The first pour, for the north pylon, took place at the end of last week and took 25 hours to complete with 1,200 cubic metres of concrete delivered in 175 loads. The second pour, for the south pylon, has just been completed in 24 hours and 45 minutes with 1,398 cubic metres delivered in 200 loads.
The concrete is being used in the bases of the pylons and in total some 120,000 cubic metres of technically complex mixes will be supplied over a period of 29 months during construction of the new bridge.
The 1,200 cubic metre pour for the north pylon required 478 tonnes of cement, 1,311 tonnes of 20/4 limestone, 450 tonnes of limestone fines and 450 tonnes of fine sand for the C40/50 CIIIB concrete mix.
The concrete started its initial set two hours after batching and will reach the required strength after 28 days. Due to the cement type used, the concrete will continue to gain strength for up to 10 years.
During the 25-hour pour, each load of concrete was tested before leaving the batching plant, and site laboratories will continue to test for compressive strength at seven, 28 and 56 days. To comply with the required specification, the concrete must reach 50N/square millimetre at 28 days.
Craig Williamson, CEMEX regional director - Northern & Scotland, commented: ‘The pours were a challenge and we are delighted they were successful. Sixty-five CEMEX colleagues were involved directly in the pours with input from additional colleagues from other areas of the business to ensure all the materials were available at the plants for batching the concrete.’
To service the Mersey Gateway’s concrete requirements, two new Liebherr concrete batching plants were built by CEMEX, one on each side of the river, close to the construction site. The south plant was erected in Runcorn in December 2014 and the north plant was erected in Widnes at the beginning of this year.
