半干法脱硫灰蒸压加气混凝土的制备及性能研究

Preparation and Performance Evaluation of Semi Dry Desulfurization Ash Autoclaved Aerated Concrete

利用半干法脱硫灰制备蒸压加气混凝土,研究不同脱硫灰掺量对蒸压加气混凝土抗压强度、干密度、吸水率等性能的影响。采用MATLAB和IMAGE J的图像分析方法,研究并揭示蒸压加气混凝土孔隙率及气孔直径分布的变化规律,通过X射线衍射(XRD)及扫描电子显微镜(SEM)分析其水化产物。结果表明:随着脱硫灰掺量的增加,蒸压加气混凝土抗压强度和干密度呈现出先增大后减小的趋势,而孔隙率和吸水率呈现出先降低后增大的趋势。对于孔结构,随着脱硫灰掺量的增加,1.4~5.4μm的气孔分布先降低后增大,且大于6.7μm的气孔分布逐渐增加。XRD与SEM结果表明,适宜掺量的脱硫灰有利于托贝莫来石生成,增强托贝莫来石的结晶度,使得托贝莫来石的空间分布更加紧密,提高蒸压加气混凝土的力学性能。研究结果表明,10%~20%掺量的脱硫灰制备蒸压加气混凝土,可满足A3.5 B06级蒸压加气混凝土的性能指标要求。

Autoclaved aerated concrete was prepared by semi dry desulfurization ash,and the effects of different desulfurization ash content on the compressive strength,dry density and water absorption of aerated concrete were studied.Through the image processing functions of MATLAB and IMAGE J,the changes of porosity and the relationship between pore diameter and occurrence frequency were studied.Finally,the hydration products were analyzed by X-ray diffraction(XRD)and scanning electron microscope(SEM).The results showed that with the increase of desulfurization ash content,the compressive strength and dry density of autoclaved aerated concrete first increase and then decrease,while the porosity and water absorption first decrease and then increase.For the pore structure,with the increase of desulfurization ash content,the frequency of pores from 1.4μm to 5.4μm first decreased and then increased,and the frequency of pores greater than 6.7μm gradually increased.XRD and SEM results show that the appropriate amount of desulfurization ash is conducive to the formation of tobermorite,enhancing the crystallinity of tobermorite,making the spatial distribution of tobermorite more compact,and improving the mechanical properties of autoclaved aerated concrete.The results show that the autoclaved aerated concrete prepared with 10%to 20%desulfurization ash can meet the performance index requirements of A3.5B06 autoclaved aerated concrete.