Fan Kaixing, Wei Jie, Feng Chengdong
School of Architecture, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Tianjin Key Laboratory of Prefabricated Buildings and Intelligent Construction, School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, China.
Materials (Basel). 2025 Jun 6;18(12):2671. doi: 10.3390/ma18122671.
This study investigates the effects of supplementary cementitious materials (SCMs) on the material performance of foamed concrete containing lightweight coarse aggregates, namely hydrophobically modified expanded perlite (EP). The EP aggregates were treated with a sodium methyl silicate solution to impart water-repellent properties prior to being incorporated into the foamed concrete mixtures. Ordinary Portland cement (OPC) was partially replaced with various SCMs, namely, silica fume (SF), mineral powder (MP), and metakaolin (MK) at substitution levels of 3%, 6%, and 9%. Key indicators to evaluate the material performance of foamed concrete included 28-day uniaxial compressive strength, thermal conductivity, mass loss rate under thermal cycling, volumetric water absorption, and shrinkage. The results noted that all three SCMs improved the uniaxial compressive strength of foamed concrete, with MP achieving the greatest improvement, approximately 97% at the 9% replacement level. Thermal conductivity increased slightly with the addition of SF or MP but decreased with MK, highlighting the superior insulation capability of MK. Both SF and MK reduced the mass loss rate under thermal cycling, with SF exhibiting the highest thermal stability. Furthermore, MK was most effective in minimizing water absorption and shrinkage, attributed to its high pozzolanic reactivity and the resulting refinement of the microstructures.
本研究调查了辅助胶凝材料（SCMs）对含有轻质粗骨料（即疏水改性膨胀珍珠岩（EP））的泡沫混凝土材料性能的影响。在将EP骨料掺入泡沫混凝土混合物之前，先用硅酸钠溶液对其进行处理，以赋予其疏水性能。用不同的SCMs部分替代普通硅酸盐水泥（OPC），即硅灰（SF）、矿粉（MP）和偏高岭土（MK），替代水平分别为3%、6%和9%。评估泡沫混凝土材料性能的关键指标包括28天单轴抗压强度、导热系数、热循环下的质量损失率、体积吸水率和收缩率。结果表明，所有三种SCMs均提高了泡沫混凝土的单轴抗压强度，其中MP的改善最为显著，在9%替代水平下提高了约97%。随着SF或MP的添加，导热系数略有增加，但随着MK的添加而降低，突出了MK优异的保温能力。SF和MK均降低了热循环下的质量损失率，其中SF表现出最高的热稳定性。此外，MK在最小化吸水率和收缩率方面最为有效，这归因于其高火山灰活性以及由此产生的微观结构细化。
