Aspiring new technologies, including Terra’s Opus SCM, have the potential to solve the concrete industry’s ever-growing need for alternative supplementary cementitious materials. Opus SCM has similar properties to fly ash and is produced without burning coal.
Opus Supplementary Cementitious Material, “Opus SCM,” is a locally manufactured, engineered substitute for fly ash. Due to the conversion of coal-fired plants to gas-fired plants, and the use of lower-quality coal, traditional, quality fly ash sources are in decreasing supply. Pursuing the opportunity to expand the use of SCM in concrete resulting in higher SCM percentage and furthering CO2 reduction, Terra’s Opus SCM is poised to address significant economic, performance, and environmental needs.
Opus SCM can offset the use of 10-30% of Portland Cement in most common concrete mix designs. It is an ideal replacement for the dwindling supply of traditional fly ash that has historically been used as an SCM. Fly ash availability is questionable in the future as this product is produced by burning coal at power plants. With the current expedited timeline to close coal-fired power plants or convert to natural gas and renewable energy, fly ash supply is again dwindling.
An easy and established way to improve the environmental performance of concrete is to replace 10-25% or more of the cement content with a low-CO2 cementitious material. The supply of high quality SCMs is not currently sufficient, and it is declining. Opus powder will fill an important role as a Type F fly ash or natural pozzolan replacement. Opus SCM is expected to be commercially available in late 2022.
SCM addition is the low-hanging fruit in reducing CO2 impact of concrete because most SCMs, including Opus SCM, have a lower CO2 footprint than the Portland cement they replace. With the typical SCM replacement of cement ranging from 10-25%, there is a large and growing need for engineered SCM to cope with immediate pressure to reduce concrete CO2 footprint.
It is possible to increase cement replacement to 30% and to create a blended hydraulic cement. Such cements have been used commercially for many years but are only coming of age as a focus is increasingly placed on the CO2 performance of cement and low carbon concrete. Opus BCM is a natural intermediary between SCM and alternative cement chemistry. It uses our Opus SCM as part of a blended hydraulic cement that allows us to achieve expected performance with 30-60% less Portland cement than a traditional concrete.
BCM extends the SCM replacement concept beyond the usual 10-25% to greater than 30% replacement with similar performance. The projected CO2 reduction is 40%, depending on substitution rate. Opus BCM is expected to be commercially available in the 2023-2024 time frame.
Opus ACM is a proprietary geopolymer cement technology that reduces CO2 emissions by +45% with no tradeoffs in performance. Designed to facilitate a stepped change in sustainable concrete supply, Opus ACM was our first and most ambitious development. Rethinking the chemistry and entire supply chain of cement production – and doing so in a way that will be profitable and make use of existing downstream technology – is the most elegant and efficient way to make the cements of the future.
With decarbonization as a new goal of the cement industry, it no longer makes sense to manufacture cement in the traditional way with limestone as the main ingredient. Every pound of limestone releases almost half a pound of CO2 when burned for Portland cement, not to mention the CO2 emissions resulting from using fossil fuel heat to drive this reaction. Terra understood early on that to achieve anything close to carbon neutrality, it is much simpler to avoid releasing CO2 by changing the feedstock and pursuing alternative binder chemistries.
Opus ACM is based on the established field of geopolymer concrete (also called alkali-activated concrete) that is already being proven in commercial construction projects around the world. In the past, geopolymer concretes required byproduct materials such as fly ash, blast furnace slag, and others that are increasingly difficult to source. Terra has developed a unique manufacturing process that will support the geopolymer concrete supply chain of the future.
Opus ACM will take a phased approach to carbon neutrality. Although there is great interest in decarbonization of concrete, there is little regulatory demand, nor economic incentive at present for most projects to use any (relatively expensive) carbon-neutral cement. Terra’s philosophy is to make the best of the market that is available, so we aim to provide a cost-competitive product that also pushes the boundaries of CO2 savings.
Our first Opus ACM available will allow approximately 40-50% CO2 savings compared to a conventional Portland cement when used in comparable common concrete applications.
We believe that cheaper, better, and more sustainable cements will come from new techniques based on first principles instead of incremental improvements to the existing cement supply chain. Opus ACM is expected to be commercially available in the 2023-2025 time frame.