Biochar Amended Concrete for Carbon Sequestration

Abstract

With the rapid increase in built-up areas around the world, and the emergence of new cities, there is a potential of sequestering carbon in civil infrastructures. Biochar is the by-product of the pyrolysis of biomass, which can be introduced to the cement mortar and the cement concrete, as a replacement of cement as well as an additive. Biochar is effective in the carbon sequestration activity and results in the high internal curing action due to the high-water absorptive capacity. As the percentage of biochar increases the amount of carbon dioxide adsorbed is also observed to increase. However, it is imperative that biochar addition should not compromise the strength characteristics of concrete. As a well-accepted fact, the pozzolanic activity plays large importance on the durability and the strength gain of concrete. The present study is aimed at investigating the pozzolanic activity of the biochar. Biochar specimens were subjected to different pre-treatments, and the corresponding changes in the pozzolanic activity were studied. The biomass used for the study was locally available coconut shells and the pre-treatment was done with the 0.1N HCl. The pozzolanic activity was checked by calculating the amount of Ca(OH)2 fixation during the titration. It was observed that treatments at higher temperatures have no significant effect on the pozzolanic activity. And this suggests that pre-treatment of biochar at room temperature is enough for enhanced pozzolanic activity. The study has reaffirmed the potential use of biochar in making sustainable concrete fit for carbon sequestration.