Green Cement: The key to building a sustainable future

Global climate change has become the hot topic in sectors spanning from development, policy, planning and foreign relations to security, energy, transportation and, surprisingly, cement.

Cement, the binding ingredient used to create concrete, is not usually the first thing that comes to mind when discussing climate change. However, the manufacture of cement results in 5-7% of yearly global anthropogenic greenhouse gases. The post-Kyoto international consensus is that action must be taken on climate change. If global CO2 equivalent is to be stabilized at double pre-industrial levels (550 ppm), then the cement industry will need to find a way to reduce their emissions.

There are two major sources of CO2 resulting from the production of cement. The first source of emissions results from the extremely high (1450 °C) kiln temperatures needed to modify the raw materials. Fossil fuels are commonly used for this process due to their high energy content, abundance and low costs. The second source of CO2 results from the calcination of limestone (mainly CaCO3) to form the main binding ingredient of cement (CaO). The chemical conversion results in CO2 as shown below.
CaO3 + heat --> CO2 + CaO

Thus for every ton of cement manufactured there is a ton of CO2 emitted into the atmosphere. Current focus on reducing emissions includes the use of renewable fuels in the kiln, improved kiln efficiency and the addition of admixtures (e.g. fly ash, slag). Although these solutions are beneficial, they do not offer long-term solutions; the supply of alternative fuels is insufficient, kiln efficiency is nearing its limit and the amount of admixtures is determined by building codes. The true sustainability of the cement industry must come from a new and innovative alternative binder.

Project mission:

Utilize the state of the art research facilities at UC Berkeley to research, test and advance the state of knowledge of alternative cementitious binders.

Potential impact:

As cement consumption will continue to rise, particularly in developing countries, low CO2 cement is essential in addressing global climate change. The university research environment offers numerous benefits that are needed to provide the scientific assurances required of such a new technology.

Fundamental research into green cement will provide the foundation for the long-term sustainability of the built environment.

Required resources:

1. Total project needs: $12,000
2. Other:

   The funding will be used in two manners. Firstly, to support the researcher(s) in conducting the experiments. Secondly, the funds enable the purchasing of testing material, use of laboratory equipment and similar expenditures anticipated to occur during the project.

Links to external blogs or wikis:

• http://bigideas2.berkeley.edu/BBB%202007/Anderson_Green%20Cities.pdf

Additional info:

The research environment and the expert faculty at UC Berkeley offer one of the best locations for researching low CO2 cements. In collaboration with the faculty of the Civil Engineering department, the research will focus on finding a real application that can play a crucial role in combating global climate change. The initial stage of the project shall focus on an in-depth analysis of the currently discussed alternatives (e.g. high volume fly ash, magnesia cements, sulfo-aluminate cements) to determine the best long-term solution. After the selection stage, material testing and research will be undertaken in a laboratory environment to address performance, durability and application concerns. Consequently, field testing of the material in real applications will be undertaken with assistance from practicing engineers, construction experts and cement companies.

Links about the cement industry:
http://www.wbcsdcement.org http://www.holcim.com/CORP/EN/id/1610644626/mod/gnm50/page/editorial.html http://www.concretecentre.com/main.asp?page=154