选用CO2体积浓度为3%的低浓度碳化试验研究了水胶比及粉煤灰与矿粉单双掺对混凝土碳化性能的影响。通过对比试验,分析了低CO2浓度下碳化深度与抗压强度之间的相关性,并采用XRD研究了混凝土的碳化产物,显示了物相分析结果与碳化试验结果的一致性。结果表明,低浓度碳化试验结果能很好反映理论规律,并且碳化周期长时与抗压强度之间具有较好的对应关系。进行低浓度加速碳化试验时,建议采用混凝土的碳化龄期为90d。XRD分析表明,混凝土的碳化速率与其内部可碳化物质CH的含量密切相关。
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.