CARBON DIOXIDE SEQUESTRATION IN FOAMED CONCRETE

Abstract

 The reduction of CO₂ emission from various productions and service processes has been already recognized to be not enough, CO₂ sequestration is necessary for decreasing the concentration of CO₂ in the atmosphere. In this study, the author proposed a new method for sequestrating CO₂, which encloses CO₂ bubbles into foamed concrete, and then investigated the strength, water absorption, drying shrinkage, alkalinity, CO₂ uptake caused by the carbonation, and micro-structure, etc. of CO₂ -foamed concrete (CFC) and Air-foamed concrete (AFC) using different kinds of cement. The experimental results show that (1) Mixing CO₂ bubbles into concrete didn't harm 28-days compressive strength and flexural strength in case of using ordinary Portland cement, and didn't increase drying shrinkage of foamed concrete. (2) The pH of CFC with 3 months age was kept to be more than 12.0, when CO₂ content was below 60% by volume, (3) Internal CO₂ bubbles yielded a little increase of CaCO₃, and (4) CO₂ sequestration in CFC was mainly structural trapping rather than carbonation.