Verification Method of Direct Air Capture by Cementitious Material Using Carbon Isotopes

Abstract

Capturing atmospheric CO2 into cement-based materials is a way to set off the CO2 emissions of concrete production. This study proposes an experimental method to track the origin of cement paste that fixes CO2 directly from the air under natural conditions. By exposing powders of well-hydrated cement paste to air, carbonated cement paste powders are obtained with different carbonation degrees. The inorganic carbon of these carbonated samples is extracted by dissolution in phosphoric acid, and the isotopic characteristics related to 13C and 14C are measured. The experimental results show that the 14C value of carbonated cement paste can be used as an indicator for tracing the origin of carbon.