Working on behalf of Connect Plus, a team from Jackson, DB Group and Axtell has achieved a 77% reduction in CO2 by using volumetric mix trucks to pour low-carbon Cemfree concrete on the Woodford West Viaduct on the M25
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This is the first time Cemfree has been used volumetrically, increasing the potential for reducing carbon emissions on future highways projects. Cemfree was piloted at the Woodford West Viaduct to pour a concrete hardstanding underneath the structure. This initial application was for 52 m3 of concrete, leading to a saving of 9.4 t of CO2 when compared to a conventional mix, thus reducing the environmental impact.
Jackson has been working with low carbon concrete for the past few years, however, it has always been challenging to use on the M25, due to the availability of batching plants, which usually shut at night.
Instead, this trial has proven the suitability of volumetric mix trucks, which are able to produce just the right amount, and crucially, at the right time, without having to rely on a batching plant to dedicate an entire silo to the product.
Tony Sheridan, DB Group’s Commercial Manager, said: “As well as enabling significant carbon savings versus a more traditional concrete mix, Cemfree offers enhanced durability and considerable savings in water consumption. Cemfree also allows contractors to consider larger pours with fewer joints as the relatively low heat generated during the curing process leads to less cracking in the finished concrete. Interest in Cemfree has grown considerably over the past few years as environmental issues and climate change have come more into public focus.”
Jackson’s Highways Division Director, Paul Watson, said: “We’re really pleased to have introduced ultra-low carbon concrete to the M25, and credit must go to our client Connect Plus, whom, as an intelligent client, supports us to trial new materials.”
“Our work with Axtell has proven that we’re able to supply the low-carbon material at no extra cost, and without having to place a large order with a ready-mix supplier, which makes the material far more accessible to use on the M25. We hope this marks a turning point on the M25, and the wider Highways sector for using low carbon alternatives.”
Conventional concrete uses Ordinary Portland Cement (OPC) as a component which causes almost a t of CO2 per t of material produced. The manufacturing process of OPC contributes 8 – 10% of global greenhouse gas emissions, twice as much as aviation, and is a major contributor to construction industry emissions.
Cemfree removes the need for OPC using 95% ground-granulated blast-furnace slag and a 5% alkali activator instead. The CO2 value of Cemfree for this particular project was 114 kg per t, 77% lower than conventional mixes, but can be up to 80%.
Andy Dean, CEO of Connect Plus, said: “Connect Plus is committed to reducing carbon emissions across the M25 network and we’re thrilled to be supporting this progressive innovation”.
Andrew Axtell, proprietor of Axtell said: “We’re keen to offer this low-carbon cement alternative as part of our various offerings as we know that this is definitely the future.”