不同生物质炉渣对蒸压加气混凝土浆料性能与力学性能的影响

Effects of Different Biomass Slags on Slurry Properties and Mechanical Properties of Autoclaved Aerated Concrete

在电厂利用生物质发电过程中,不同焚烧工艺产生的焚烧炉渣的成分和性质不同,这为其资源化利用带来了较大的难题。本研究以生物质炉渣、水泥、石灰为主要原料制备蒸压加气混凝土(AAC),对比研究两种主流燃烧工艺产生的炉渣对AAC制品浆料性能和力学性能的影响,并通过XRD和SEM对其水化产物及微观形貌进行过测试分析。结果表明:随着机械炉排炉渣(MGI)掺量的增加,AAC浆料的初始流动度明显下降,流动度损失增大,发气体积下降;AAC试块的比强度先增大后减小,当MGI质量分数为28%时,为兼顾AAC强度和密度的最佳掺量,抗压强度和密度分别为3.6 MPa、593.22 kg/m^(3)。循环流化床炉渣(CFBC)中大量的硬石膏和游离氧化钙会影响浆料的凝结硬化,随着CFBC掺量的增加,AAC浆料初始流动度逐渐增大,发气体积上升,AAC试块的比强度持续减小。此外,AAC中的水化产物——托贝莫来石的形态和堆积密度对制品的力学性能有着显著影响。

In the process of using biomass for power generation in power plants,the composition and properties of the incineration slag generated by different incineration processes are different,which poses significant challenges for its resource utilization.In this study,autoclaved aerated concrete(AAC)was prepared using biomass slag,cement and lime as the main raw materials.The effects of slags generated by two mainstream biomass incineration processes on the slurry properties and mechanical properties of AAC products were studied.Hydration products and micromorphology of AAC were also systematically studied by SEM and XRD.The results show that with the addition of mechanical grate incinerator slag(MGI),the initial fluidity decreases significantly,the fluidity loss of slurry increases,the gas volume decreases and the specific strength of AAC increases first and then decreases.When the MGI mass fraction is 28%,it is the best dosage to take into accont the strength and density of ACC,with the compressive strength and density are 3.6 MPa and 593.22 kg/m^(3),respectively.Due to the presence of a large amount of anhydrite and free calcium oxide in circulating fluidized bed combustion slag(CFBC),the solidification and hardening of the slurry are affected.With the increase of CFBC content,the initial fluidity of AAC slurry gradually increases,the gas generation volume increases,and the specific strength of AAC test blocks continues to decrease.In addition,the morphology and bulk density of tobermorite,hydration product,in AAC have a significant impact on the mechanical properties of the product.