One of the most significant changes to Australian cement technology and resulting innovation in concrete in the past 40 years.
~ Tony Thomas, Chief Engineer, Boral Concrete
ENVISIA® was designed from the outset to reduce the carbon emissions associated with concrete production. Cement manufacture is a key carbon-emitting step in concrete production, so less cement can mean lower levels of embedded carbon in concrete. For many years industrial by-products, such as fly ash from coal-fired power stations and slag from iron production, had been added to reduce the amount of cement used in concrete. But they can also affect performance and slow down the rate at which concrete strengthens.
That's where ZEP® comes in – the proprietary technology that ENVISIA® uses. The technology allows ENVISIA® to meet the same performance standards as conventional concrete. Indeed, by many measures it performs better. For instance, laboratory tests have shown that ENVISIA® can provide up to a 50 per cent reduction in shrinkage over conventional1 concrete2. This can simplify the construction process by allowing the production of larger slabs with fewer joints.
ENVISIA® can also reduce creep strain by up to 40 per cent over conventional1 concrete with comparable characteristics2. At the same time it delivers concrete plastic, placement and finishing properties similar to normal Portland cement-based concretes. Crucially, there are no additional safety handling requirements – an important distinction from some other lower carbon concretes that are beginning to enter the Australian market, such as geopolymers, which make use of highly alkaline activating agents, which are not used in ENVISIA®.
ENVISIA® has been used to meet the sustainability requirements for the newly rebuilt Stokehouse restaurant in Melbourne and 333 George Street – a retail/office development in the heart of Sydney's CBD. ENVISIA® has also been used in blinding slabs within the first phase of the $6 billion Barangaroo South waterfront development in Sydney.
Several names were considered, but ENVISIA® was eventually chosen because it combines the concepts of sustainability (ENV) and vision for the future (VISIA). ZEP® is a nod to the band Led Zeppelin, whose music was playing when the development team hit upon the winning formula.
1. Concrete containing currently used blends of Portland cement and SCM that do not include ZEP® technology, that have been in common use for the given applications prior to the availability of ZEP® technology and compliant with AS1379
2. Boral Laboratory Testing August 2012 – June 2013