BASIC STUDY ON CARBON DIOXIDE ABSORPTION CHARACTERISTIC OF CONCRETE

Abstract

Concrete absorbs carbon dioxide (CO2) because carbonation occurs due to reacting to CO2. Therefore, it is considered that concrete may contribute to carbon neutrality. The purpose of this study is to experimentally understand the CO2 absorption characteristics of concrete by filling CO2 into a container with concrete specimens and measuring the CO2 concentration in the container. A sealed container and a CO2 concentration meter are applied as the experimental instruments. CO2 is supplied into the container placing specimens until the predefined CO2 concentration value. The CO2 concentration in the container is measured with the elapsed time. The CO2 absorption characteristic is gained as the reduction ratio of the CO2 concentration when the reduction value is gained from the difference between the initial concentration ratio in the container and the measured ratio at the final measuring time. The conditions are focused on the number of specimens, fine aggregate types, and the water-cement ratio. As a result, under the high CO2 concentration condition, it is found that the CO2 absorption characteristics depend on the concrete volume, the water-cement ratio, and fine aggregate types. Also, concrete is difficult to absorb CO2 with increasing the CO2 supply cycle.