Chen Gonglian, Li Fenglan, Jing Pengfei, Geng Jingya, Si Zhengkai
Department of Civil Engineering, School of Civil Engineering and Communication, Huayuan Campus, North China University of Water Resources and Electric Power, No. 36 Beihuan Road, Zhengzhou 450045, China.
International Joint Research Lab for Eco-building Materials and Engineering of Henan, Huayuan Campus, North China University of Water Resources and Electric Power, No. 36 Beihuan Road, Zhengzhou 450045, China.
Materials (Basel). 2021 Jan 11;14(2):339. doi: 10.3390/ma14020339.
With the premise of investigating mechanical properties, the thermal conductivity of autoclaved aerated concrete (AAC) is a key index of self-insulation block walls for building energy conservation. This study focused on the effect of pore structures on the mechanical performance and thermal conductivity of AAC with the comparison of AAC base materials. Different kinds of AAC and their base materials were prepared and experimentally investigated. While maintaining a consistent mix proportion of the AAC base material, the pore structure of AAC was changed by the dosage of aluminum power/paste, foam stabilizer, and varying the stirring time of aluminum paste. The steam curing systems of AAC and the base material were determined based on SEM (Scanning Electronic Microscopy) and XRD (X-Ray Diffraction) tests. With almost the same apparent density, the pore size decreased with the increasing content of foam stabilizer, and the mixing time of aluminum paste and foam stabilizer has a great influence on pore size. The thermal conductivity test and compressive test results indicated that that pore size had an effect on the thermal conductivity, but it had little effect on the compressive strength, and the thermal conductivity of sand aeration AAC was 8.3% higher than that of fly ash aeration AAC; the compressive strength was 10.4% higher, too. With almost the same apparent density, the regression mathematical model indicates that the thermal conductivity of AAC increased gradually with the increase of pore size, but it had little effect on the compressive strength. From the test results of basic mechanical properties, the mechanical model of cubic compressive strength, elastic modulus, axial compressive strength, and splitting tensile strength was obtained. The proposed stress-strain relationship model could well describe the relationship of AAC and the base material at the rising section of the curve.
在研究力学性能的前提下，蒸压加气混凝土（AAC）的导热系数是建筑节能自保温砌块墙体的关键指标。本研究通过对比AAC基础材料，聚焦孔隙结构对AAC力学性能和导热系数的影响。制备了不同种类的AAC及其基础材料并进行实验研究。在保持AAC基础材料配合比一致的情况下，通过铝粉/铝膏用量、泡沫稳定剂以及改变铝膏搅拌时间来改变AAC的孔隙结构。基于扫描电子显微镜（SEM）和X射线衍射（XRD）测试确定了AAC及其基础材料的蒸汽养护制度。在表观密度几乎相同的情况下，孔径随泡沫稳定剂含量的增加而减小，铝膏与泡沫稳定剂的搅拌时间对孔径有很大影响。导热系数测试和抗压测试结果表明，孔径对导热系数有影响，但对抗压强度影响较小，砂加气AAC的导热系数比粉煤灰加气AAC高8.3%；抗压强度也高10.4%。在表观密度几乎相同的情况下，回归数学模型表明，AAC的导热系数随孔径的增大而逐渐增大，但对抗压强度影响较小。从基本力学性能测试结果中，得到了立方体抗压强度、弹性模量、轴心抗压强度和劈裂抗拉强度的力学模型。所提出的应力-应变关系模型能够很好地描述AAC及其基础材料在曲线上升段的关系。
