2025 Volume 78 Issue 1 Pages 407-415
We conducted research of carbon dioxide fixation behavior and rate of CO2 diffusion into hardened cement specimens of different pre-curing period before starting accelerating carbonation curing for ordinary portland cement（OPC）, OPC mixed with ground granulated blast furnace slag（BB）, and OPC mixed with an amorphous calcium aluminate based accelerator（ACC）respectively. We prepared two types of hardened cement specimens, the first was in the case of powder shape hardened cement paste specimen which is designed to avoid carbon dioxide diffusion’s influence as much as possible and to evaluate fixation capacity of carbon dioxide, as a result carbon dioxide content increases with getting pre-curing period longer in any cases after accelerating carbonation curing. The other one was in the case of balky mortar specimens which evaluates carbon dioxide diffusion, carbon dioxide diffusion got slower with getting pre-curing period longer in the case of OPC, BB, however ACC’s carbon dioxide diffusion was almost constant even pre-curing period is different. The mineral composition and hydrate before carbonation differed by difference of cement type. Phase diagram after carbonation was also changed. In fact, more vaterite was formed with getting pre-curing period longer in any case, especially its phenomenon was remarkable in ACC system.
