In this paper, a multi-scale analysis of the effect of foam on chemo-mineralogical and microstructural features of the soil–cement–water system is presented. Time-dependent mineralogical and microstructural changes induced by foam were monitored at increasing curing times by means of X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and mercury intrusion porosimetry. Addition of foam does not alter chemo-physical evolution of the soil–cement–water system in terms of either cement hydration or pozzolanic reactions. Large voids are present in the samples as footprints of air bubbles upon mixing, increasing the porosity of samples but not altering their matrix microstructure. Macroscopic behaviour of treated samples was investigated by direct shear tests. Chemo-physical evolution induced by adding cement is the main factor responsible for mechanical improvement shown by the treated samples. Sample porosity induced by adding foam plays a key role in the mechanical response of lightweight cemented samples, inducing a transition of stress–strain behaviour from brittle and dilative to ductile and contractile as foam content is increased.

中文翻译：

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轻质水泥土的化学力学行为

本文对泡沫对土壤-水泥-水系统的化学矿物学和微观结构特征的影响进行了多尺度分析。通过增加的固化时间，通过X射线衍射，热重分析，扫描电子显微镜和压汞法，监测了泡沫引起的随时间变化的矿物学和微观结构变化。就水泥水合作用或火山灰反应而言，添加泡沫不会改变土壤-水泥-水系统的化学物理演化。样品中的大空隙作为混合时气泡的痕迹存在于样品中，增加了样品的孔隙率，但并未改变其基质微观结构。通过直接剪切试验研究了处理样品的宏观行为。通过添加水泥引起的化学物理演变是导致处理样品显示出机械性能改善的主要因素。通过添加泡沫引起的样品孔隙率在轻质胶结样品的机械响应中起着关键作用，随着泡沫含量的增加，其导致应力-应变行为从脆性和扩张性转变为韧性和收缩性。