Greener cement for construction may be already well within reach, based on a new study carried out by researchers from MIT in the United States and CNRS in France. While modern-day cement has its roots extending back to the mid-1700s, the ratios of the two main ingredients, calcium (from limestone) and silica (from clay), which are used to manufacture it can vary widely, and had not been studied to this extent before.
The potential reduction in carbon emissions from the production of cement could be as much as 60 percent, according to Dr. Roland Pellenq, the senior research scientist for the study. The production of cement is presently one of the largest contributing industrial sources of CO2 in the atmosphere. Consequently, changes in its manufacture could have significant and widespread benefits if a better production method is developed.
“In conventional cements, Pellenq explains, the calcium-to-silica ratio ranges anywhere from about 1.2 to 2.2, with 1.7 accepted as the standard. But the resulting molecular structures have never been compared in detail. Pellenq and his colleagues built a database of all these chemical formulations, finding that the optimum mixture was not the one typically used today, but rather a ratio of about 1.5.” Production of cement at this ratio would, according to the researchers, allow significant reductions in CO2 emissions. In addition to the emissions benefit, the researchers also found that cement produced at this ratio would be stronger and more fracture resistant.
Adaptation of this research will still take time to implement, as the new formulations will need to be studied by engineering standards organizations before this becomes the new standard for manufacture.
There could even be a synergistic benefit in this, by significantly reducing the carbon emissions in the production of the cement, and then further reducing emissions due to less cement being needed due to the improved strength of the material.
via: MIT Press Release
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