One novel lightweight building material was successfully manufactured using magnesium oxysulfate (MOS) cement as binder and foam and/or rice husk as inert fillers in this paper. It behaves much higher specific strength and lower environmental load than normal concretes prepared by Portland cement, natural sand and aggregates. To improve the mechanical strength and water resistance of MOS matrix, three kinds of weak acids were incorporated at low levels. On the basis of the modified MOS matrix, foam, rice husk, and the mixture of foam and rice husk were added at variable dosages as fillers to prepare MOS cement based lightweight materials. Mechanical strength, bulk density and compressive strength/volume deformation of these materials were evaluated after variable wetting-drying cycles. At the same time, phase composition and microstructure of typical samples were studied using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Opto-digital Microscope (OM) and Scanning Electron Microscope (SEM) tests. Experimental results indicated that the addition of 0.5% citric acid by MgO weight can greatly enhance compressive strength and water resistance due to the formation of finer needle-like crystals of 5•1•7 phase instead of 3•1•8 phase. The higher incorporation of foam and rice husk decreases bulk density and mechanical properties of MOS cement pastes. With a density of as low as 1000 kg/m³, the compressive strength of MOS cement based lightweight materials can reach higher than 12 MPa. The wetting-drying treatment leads to a negative effect on both compressive strength and volume stability of these materials, due to the transformation of unreacted MgO into Mg(OH)₂ crystals upon water immersion. On the other hand, the coupling effect of water-swelling and drying-shrinkage induces the formation of micro cracks in specimens. A proper addition of foam bubbles and rice husk presents the better resistance to wetting-drying cycles. Therefore, the MOS cement based lightweight material could be widely applied to inner partition walls and structural component, and its long-term service behavior should be further assessed.

本文成功地使用氧硫酸镁（MOS）水泥作为粘合剂，并使用泡沫和/或稻壳作为惰性填料成功地制造了一种新型的轻质建筑材料。它比波特兰水泥，天然砂和骨料制备的普通混凝土具有更高的比强度和更低的环境负荷。为了提高MOS基体的机械强度和耐水性，低含量加入了三种弱酸。在改性的MOS基体的基础上，以可变的剂量添加泡沫，稻壳以及泡沫和稻壳的混合物作为填料，以制备基于MOS水泥的轻质材料。这些材料的机械强度，堆积密度和抗压强度/体积变形在不同的干湿循环后进行了评估。同时，使用X射线衍射（XRD），傅立叶变换红外光谱仪（FTIR），光电显微镜（OM）和扫描电子显微镜（SEM）测试研究了典型样品的相组成和微观结构。实验结果表明，由于形成了5•1•7相而不是3•1•8相的针状晶体，MgO重量增加0.5％柠檬酸可以大大提高抗压强度和耐水性。泡沫和稻壳的较高掺入降低了MOS水泥浆的堆积密度和机械性能。密度低至1000 kg / m 以MgO重量计5％的柠檬酸可以形成5•1•7相而不是3•1•8相的细针状晶体，因此可以大大提高抗压强度和耐水性。较高的泡沫和稻壳掺入量会降低MOS水泥浆的堆积密度和机械性能。密度低至1000 kg / m 以MgO重量计5％的柠檬酸可以形成5•1•7相而不是3•1•8相的细针状晶体，因此可以大大提高抗压强度和耐水性。较高的泡沫和稻壳掺入量会降低MOS水泥浆的堆积密度和机械性能。密度低至1000 kg / m^{如图3所示}，基于MOS水泥的轻质材料的抗压强度可以达到高于12MPa。润湿干燥处理对这些材料的抗压强度和体积稳定性均产生负面影响，这是由于水浸没时未反应的MgO转变为Mg（OH）₂晶体。另一方面，水溶胀和干燥收缩的耦合作用导致样品中微裂纹的形成。适当添加泡沫气泡和稻壳可以更好地抵抗干湿循环。因此，基于MOS水泥的轻质材料可广泛应用于内部隔墙和结构部件，并应进一步评估其长期使用性能。