Cemex UK has developed a new, ready-mixed concrete mix, which is being used in the UK for the first time, for the construction of the foundations of new Terminal 2 building at Heathrow Airport.
The new mix design, developed in close collaboration with Laing O’Rourke as part of its joint venture with Ferrovial Agroman for BAA, incorporates high levels of pulverised fuel ash (pfa) combined with high range water reducing admixtures to lower the heat generation in the concrete to minimise thermal gradients in the structure and reduce the risk of early age thermal cracking.
The innovative concrete mix was developed at Cemex’s UK National Technical Centre in Southam, Warwickshire over a two month period as part of the UK£7m contract secured by Cemex for supplying over 100,000m3 of ready-mixed concrete towards the construction of Terminal 2.
The new concrete mix incorporates factory blended cement from CEMEX’s new flagship cement plant in Tilbury, Essex, CEM II/B-V, in combination with pulverised fuel ash which is a by-product from coal fired power stations, and limestone aggregates to produce a low heat concrete.
The relatively high proportion of pfa in the mix has the additional advantage of reducing the overall carbon footprint. The emissions in the CEMII alone are reduced by 25% when compared to CEMI.