Cement used in structural concrete accounts for 60% of all cement. Thus, the amount of CO_2 emission by cement in structural concrete in a year is about 5% of the amount emitted by mankind. However, the Life Cycle Assessment (LCA) of structural concrete emits CO_2 not only at the product stage but also at the use stage after construction. In this paper, carbon neutrality is viewed from an economic point of view. Then a rough indicator is presented to grasp the CO_2 emissions of structural concrete. This paper also shows that LCA of structural concrete should consider not only the materials but also the maintenance phase. And low-carbon technologies currently in use is introduced. Then the need for multi-cycle structural concrete with a circular economy is presented. Moreover, it is estimated that CO_2 emissions due to disasters in the use stage could be enormous. The carbon neutrality of concrete is not a risk but an opportunity for us.
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