Carbon emission analyses of concretes made with recycled materials considering <scp>CO<sub>2</sub></scp> uptake through carbonation absorption
Jianzhuang Xiao, Yu Xiao, Yun Liu, Tao Ding
Abstract
Abstract The effect of incorporation of recycled powder and CO 2 absorption of concrete was not considered in the previous life cycle assessment studies. This study evaluated the carbon emission of recycled concrete with different replacement rate of recycled powder and recycled coarse aggregate, taking the carbon absorption in storage and service phase into consideration. The carbon absorption model of recycled concrete with recycled powder was optimized and validated by rapid carbonization tests. It is found that concrete with recycled powder has favorable carbon absorption capacity and can greatly reduce carbon emission. The carbon emission of recycled concrete with recycled powder decreased 12.4–52.2% when compared to normal concrete, and with the increase in the replacement of recycled materials, this advantage becomes more obvious. The evaluation results show that the raw material production and transportation phase are the two main contributors to the carbon emission of recycled concrete, accounting for 67.03–85.81% and 4.01–15.27%, respectively. The evaluation results also show the compensation benefits in storage and service phase from carbon absorption account for 1.58–26.93%. Meanwhile, the long‐distance delivery of natural coarse aggregates makes it possible for recycled concrete to be widely applied.