Abstract This study investigates the instability of fresh geopolymer foam concrete (GFC) synthesised through the pre-foaming technique, particularly at ultra-low densities (430–460 kg/m3). Initial setting time and the yield stress development with time were measured for the base mixes and correlated to the level of stability. We observed that the foam stability was established through the yield stress development at the start, well before the initial setting of the binder. The settlement was noticeably reduced when the initial yield stress satisfied the stability criterion to prevent drainage. The base mix with the highest initial yield stress and the fastest yield stress development rate displayed the highest level of stability in the fresh GFC. Apart from the direct measurement of settlement, foam stability was well reflected in the hardened properties of the GFC such as pore size distribution, pore homogeneity and mechanical strength.

中文翻译：

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屈服应力发展对加气地质聚合物混凝土泡沫稳定性的影响

摘要 本研究调查了通过预发泡技术合成的新鲜地质聚合物泡沫混凝土 (GFC) 的不稳定性，特别是在超低密度 (430–460 kg/m3) 下。测量基础混合物的初始凝固时间和屈服应力随时间的发展，并与稳定性水平相关联。我们观察到泡沫稳定性是通过开始时的屈服应力发展建立的，远在粘合剂的初始凝固之前。当初始屈服应力满足防止排水的稳定准则时，沉降明显减少。具有最高初始屈服应力和最快屈服应力发展速率的基础混合物在新鲜 GFC 中显示出最高水平的稳定性。除了直接测量沉降，