Abstract:
CO_2 mineralization curing concrete technology makes concrete rapid forming and improve mechanical properties in a short time,greatly shorten the curing cycle,improve production efficiency,is a large-scale industrial application prospect of carbon dioxide utilization. In this paper,the CO_2 curing of aerated concrete based on industrial solid waste raw materials was mainly studied,and the effects of raw material ratio,curing pressure and curing method on the CO_2 mineralization reaction were mainly studied. The formula of carbon dioxide curing aerated concrete is mainly determined by the compressive strength and carbon fixation performance of the specimen. The change characteristics of the reaction products under different curing conditions were characterized by SEM and XRD,and the pore distribution before and after CO_2 curing was measured by mercury intrusion method. The results show that the carbon fixation ratio of the specimens increases with the increase of the curing pressure when the aerated concrete after natural curing for 4 days is cured for 2 hours. Low pressure curing and stepped curing are beneficial to reduce the mechanical strength loss of the specimens. The higher the CO_2 concentration/partial pressure of the second stage of cascade curing is,the higher the apparent carbon fixation rate of the specimens is; Under the same CO_2 curing condition,SEM observes that the products of mineralization reaction has different morphology,such as spherical and spindle shape,XRD analysis shows that there are three different crystal forms of calcium carbonate; after CO_2 curing,the micropores with pore diameter in the range of 0.01-0.10 μm decrease significantly,and the higher the apparent carbon fixation ratio is,the more significant the filling effect on the aerated concrete is.