Carbonated concrete brick capturing carbon dioxide from cement kiln exhaust gas

Abstract

In this study, a new type of carbonated concrete brick has been developed, which can capture CO2 from the cement kiln exhaust gas. This is the first industrialization of carbonation curing by using cement kiln exhaust gas. The exhaust gas of cement kiln was directly injected to the chamber to conduct CO2 curing on concrete bricks, and the compressive strength of concrete bricks with 24 h curing using cement kiln exhaust gas was basically equivalent to that of autoclaved curing of 8 h (200 ℃, 1.2 MPa). The drying shrinkage reduced by 15 % and the frost-resistance increased by 12 % compared with autoclaved curing because the carbonation reaction creates a dense layer of calcium carbonate on the surface of bricks, which reduces their surface porosity and improves their durability. This technology can reduce the CO2 emission of cement factory. On the other hand, it can improve the early strength of concrete bricks and reduce the curing cost by 12 %− 56 % compared with autoclave curing considering with different carbon tax, which has great environmental and economic benefits.