著者
Ngoc Kien Bui Ryo Kurihara Wei Wang Manabu Kanematsu Hikotsugu Hyodo Miku Takano Hiroshi Hirao Takafumi Noguchi Ippei Maruyama
出版者
Japan Concrete Institute
雑誌
Journal of Advanced Concrete Technology (ISSN:13473913)
巻号頁・発行日
vol.21, no.3, pp.166-188, 2023-03-30 (Released:2023-03-30)
参考文献数
105
被引用文献数
1

This study investigates the wet carbonation of concrete fines with CO2 and natural air gas bubbling in a carbonation system at low temperatures. After the air- and CO2-wet carbonations, the properties of a solution and hydrated cement paste powder are determined. In the air and CO2-wet carbonations, more Ca is extracted into the solution at a low temperature of 5°C. This high Ca concentration in the solution through air-wet carbonation primarily originates from the portlandite and unhydrated phases of the cement paste. Even in solutions with high pH values, the rehydration process and C–S–H decomposition occur simultaneously in air-wet carbonation. Moreover, CO2-wet carbonation indicates that the decalcification of C–S–H occurs rapidly, even in the presence of portlandite. Air-wet carbonation presents a potential method for the direct air capture of CO2 using concrete waste fines in a short period.
著者
Ippei Maruyama Wataru Kotaka Bui Ngoc Kien Ryo Kurihara Manabu Kanematsu Hikotsugu Hyodo Hiroshi Hirao Ryoma Kitagaki Masaki Tamura Masato Tsujino Satoshi Fujimoto Takafumi Noguchi
出版者
Japan Concrete Institute
雑誌
Journal of Advanced Concrete Technology (ISSN:13473913)
巻号頁・発行日
vol.19, no.10, pp.1052-1060, 2021-10-08 (Released:2021-10-08)
参考文献数
20
被引用文献数
15

Countermeasures against carbon dioxide emissions are a concern in the construction field as well as in society. To solve this problem, a concept for new calcium carbonate concrete is proposed, and this concept is validated experimentally. In the proposed concept, calcium carbonate comprising Ca originating from demolished concrete or other Ca-containing industrial wastes and HCO3- from CO2 gas collected from the air or emitted by industrial plants acts as a binder for aggregates, which can be natural rocks or crushed demolished concrete. This short paper describes the details of the process of making calcium carbonate concrete and discusses future perspectives.