The Freeze-thaw (FT) performance of cementitious materials is dependent on the degree of saturation (DOS). It has been proposed that FT damage can occur during freezing when the DOS is greater than a critical DOS (DOS_CR). In a previous study, a systematic methodology has been developed to determine the DOS_CR of cement paste samples using high precision length change measurements during freezing and thawing in a thermomechanical analyzer (TMA). This paper explores the extension of the established methodology to mortar samples to determine their DOS_CR. The influence of the drying temperature and the characteristics of FT cycle (temperature range, heating and cooling rate) were investigated to determine their impact on the FT performance of the mortar samples. The mortar samples tested in this study were obtained by making concrete and then wet sieving the concrete to obtain mortar. Mixtures with different air void content and air void quality were prepared in this study in order to determine the impact of air void content and air void quality on the FT performance of the samples using TMA testing. The results confirm that length change measurements can be used to determine DOS_CR of mortar. A correlation considering the probability of failure was found to exist between the air void quality and the FT performance of mortar samples. The approach presented in this paper provides an alternative method that can complement other existing tests to determine the DOS_CR for use in the sorption-based model.

胶结材料的冻融（FT）性能取决于饱和度（DOS）。已经提出，当DOS大于临界DOS（DOS _CR）时，在冻结期间会发生FT损坏。在先前的研究中，已经开发出一种系统的方法来确定水泥浆样品的DOS _CR，该方法在热机械分析仪（TMA）的冻结和解冻过程中使用高精度的长度变化测量。本文探讨了将建立的方法扩展到砂浆样品以确定其DOS _CR的方法。研究了干燥温度和FT循环特性（温度范围，加热和冷却速率）的影响，以确定它们对砂浆样品的FT性能的影响。本研究中测试的砂浆样品是通过以下方法获得的：先将混凝土制成混凝土，然后将其湿筛以得到砂浆。在这项研究中，准备了具有不同气孔含量和气孔质量的混合物，以便使用TMA测试确定气孔含量和气孔质量对样品FT性能的影响。结果证实长度变化测量可用于确定DOS _CR砂浆。发现孔隙质量与砂浆样品的FT性能之间存在考虑破坏概率的相关性。本文介绍的方法提供了一种替代方法，可以替代其他现有测试以确定用于基于吸附的模型中的DOS _CR。