Experimental Research on Accelerated Carbonation of Concrete under Low CO_2 Concentration

The effect of water to binder ratio,fly ash and slag on the carbonation of concrete is investigated with low-concentration(3% CO2 in volume) carbonation test methods.The relation between the carbonation depth and compressive strength is analyzed by contrast tests.The relative intensity of carbonation products CaCO3 is determined by X-ray diffraction(XRD) analysis.It is revealed that carbonation results under low CO2 concentration coincides well with theoretical laws.There is a good relationship between carbonization depth and compressive strength of concrete when the carbonation time is long enough.The carbonation duration under low CO2 concentration is proposed at 90 days.It can also be concluded that carbonation rate of concrete is closely related to carbonizable substance CH.