CO2 uptake in fillers and supplementary cementitious materials

Carbonating fillers and supplementary cementitious materials (SCMs) before their use in concrete offers a promising approach to sequester CO 2 without compromising the performance of SCM-blended cementitious systems. This study investigates the carbonation of fillers and SCMs with CaO + MgO content ranging from 16 to 50%. Preliminary experiments were conducted to determine the optimal conditions for CO 2 uptake, and all fillers/SCMs were exposed to CO 2 under these conditions. The effects of CO 2 exposure were evaluated using thermogravimetric analysis, Fourier transform infrared spectroscopy, and x-ray diffraction. The changes in material reactivity after carbonation were also tested using a modified R 3 test. Recycled cement materials and steel slags showed substantial CO 2 uptake. Otherwise, CO 2 uptake is generally low. CO 2 exposure has minimal impact on filler/SCM reactivity.