Manuscript accepted for publication in the journal Materials and Structures A MICROSTRUCTURAL INSIGHT INTO THE HYGRO-MECHANICAL BEHAVIOUR OF A STABILISED HYPERCOMPACTED EARTH
Manuscript accepted for publication in the journal Materials and Structures A MICROSTRUCTURAL INSIGHT INTO THE HYGRO-MECHANICAL BEHAVIOUR OF A STABILISED HYPERCOMPACTED EARTH
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手稿接受发表在《材料与结构》杂志上
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. Gallipoli
中科院分区：
文献类型：
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作者：
A. Bruno;C. Perlot;J. Mendes;D. Gallipoli
使用生土作为建筑材料可以节省体现和操作能源，因为低加工成本和室内环境条件的被动调节。然而，生土必须经过机械和/或化学稳定处理，以提高刚度、强度和防水性。在这项工作中，刚度和强度提高压实生土非常高的压力高达100 MPa，而水的耐久性提高了使用碱性溶液和硅基外加剂。这些稳定方法对湿力学行为的影响进行了探讨和解释的材料的微观结构特征。刚度和强度通过无侧限压缩测试在不同湿度水平下定义，而水分缓冲能力通过标准ISO 24353（2008）规定的加湿/干燥循环来测量。至于微观结构表征，进行不同的测试（即X射线衍射法，红外光谱法，压汞孔隙度法，氮吸附），以分析稳定对材料结构和矿物学的影响。结果表明，使用碱性活化剂和硅基外加剂显着提高水耐久性，同时保持良好的机械和水分缓冲性能。同样，在非常高的压力下压实会产生高水平的刚度和强度，与标准砖石的刚度和强度相当。然后将这种宏观行为与微观观察联系起来，以澄清稳定作用在不同尺度上影响生土性质的机制。
The use of raw earth as construction material can save embodied and operational energy because of low processing costs and passive regulation of indoor ambient conditions. Raw earth must however be mechanically and/or chemically stabilised to enhance stiffness, strength and water durability. In this work, stiffness and strength are enhanced by compacting raw earth to very high pressures up to 100 MPa while water durability is improved by using alkaline solutions and silicon based admixtures. The effect of these stabilisation methods on hygro-mechanical behaviour is explored and interpreted in terms of the microstructural features of the material. Stiffness and strength are defined at different humidity levels by unconfined compression tests while the moisture buffering capacity is measured by humidification/desiccation cycles as prescribed by the norm ISO 24353 (2008). As for the microstructural characterisation, different tests (i.e. X-Ray diffractometry, Infrared Spectroscopy, Mercury Intrusion Porosimetry, Nitrogen Adsorption) are performed to analyse the effect of stabilisation on material fabric and mineralogy. Results indicate that the use of alkaline activators and silicon based admixtures significantly improves water durability while preserving good mechanical and moisture buffering properties. Similarly, the compaction to very high pressures results in high levels of stiffness and strength, which are comparable to those of standard masonry bricks. This macroscopic behaviour is then linked to the microscopic observations to clarify the mechanisms through which stabilisation affects the properties of raw earth at different scales.