Roman Cement is an economically and technically viable alternative to Portland Cement as it has been produced and consumed for the past 150 years. With only modest capital requirements, Roman Cement's environmental benefits surpass those of many other CO2 reduction efforts, including a number of heavily mediatized alternative energy projects.
Why Roman Cement is good for the environment.
Cement is one of the main ingredients of concrete, the most abundant material made by man. In 2014, the worldwide production of cement was just under 4 billion tons, and each ton of cement produces approximately 0.9 tons of CO2 which is emitted in the atmosphere. This makes the cement industry one of the largest producers of anthropomorphic greenhouse gases in the world, representing an estimated 5% of all CO2 emissions.
Roman Cement enables a high substitution rate of cement with other materials that have a neutral or near-zero carbon footprint. In fact, many materials that can be used as cement substitutes in Roman Cement are by-products from other industrial processes or post-consumer recycling, such as coal ash, steel slag, blast furnace slag, recycled glass, etc. Other materials that can be used include natural pozzolans, such as different types of volcanic rock.
While a number of technologies have explored ways to achieve greater cement substitution, market acceptance has been slow, as many of these technologies, if not all, suffer from one or several of the following disadvantages: they are not cost effective, they are too complex too implement, they trade-off cement substitution for performance, or they require too much capital to be atractive to investors. The Roman Cement technology is not plagued by any of these drawbacks, and it is perfectly possible to reduce cement content by 70% while retaining satsifactory performance, at a lower cost than Ordinary Portland Cement, and without changing the fundamental process by which concrete is made today.
In addition to its beneficial effect on reducing CO2 emissions, the Roman Cement technology also offers a means to eliminate waste from unused industrial by-products. For example, more than 1 billion tons of coal ash is being generated in the world every year. Over two thirds is landfilled, leading to enduring environmental issues. Roman Cement offers a viable alternative to employ even poorly reactive coal ash that is traditionally considered unsuitable as a cement substitute.
An example to put the benefits of Roman Cement in perspective.
The recently completed BrightSource Ivanpah Solar Electric Generating System located in California’s Mojave Desert is a massive project. It is by all accounts the largest solar thermal power plant in the world. It began commercial production in 2013 and, when fully operational, will reportedly produce 377 MW of electricity and reduce carbon dioxide (CO2) emissions by more than 400,000 tons per year. The Ivanpah project cost $2.2 billion and has consistently been under scrutiny for its environmental impact since its commissioning.
The capital cost of building a Roman Cement grinding-blending facility capable of producing 1 million tons per year of blended cement containing 33% Portland cement and 67% Cement Substitute is about $45 to $60 million. Reducing the amount of Portland cement in 1 million tons of blended cement by 670,000 tons will avoid approximately 500,000 tons of CO2 emissions per year. Compared to the cost of building the aforementioned solar power plant required to obtain similar CO2 emissions reductions ($2 to $2.5 billion to reduce CO2 emissions by 400,000 tons per year), an investment of $45 to $60 million is trivial.
Size of a 1 million ton/year Roman Cement plant
Aerial picture of Ivanpah Solar Plant, California