Changes in Pore Characteristics of Alkali-activated Slag Paste after Freeze-thaw Cycles

International Conference on Manufacturing Technology, Materials and Chemical Engineering

机械制造;材料科学;化学工业

Xueqian, Yin^1 ; Lin, Liu^1,2 ; Haoyu, Dai^1 ; Sainan, Qin^1

Jiangsu Engineering Research Center of Concrete Cracking, College of Civil and Transportation Engineering, Hohai University, Nanjing

210098, China^1

Jiangsu Research Institute of Building Science Co., LTD., Nanjing

210008, China^2

关键词: Alkali activated slags;    Freeze thaw actions;    Freeze-thaw cycles;    Freeze-thaw resistance;    Low-temperature calorimetry;    Pore characteristics;    Temperature changes;    Testing temperature;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/392/3/032014/pdf
DOI  :  10.1088/1757-899X/392/3/032014

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The freeze-thaw resistance of Alkali-activated slag (AAS) material is one of its important properties when applied in cold areas, which is intrinsically related to its pore structure. In order to investigate changes in the pore characteristics of AAS paste subjected to freeze-thaw action, AAS paste samples after different freeze-thaw cycles (i.e., 0, 3, 9, 15 cycles) are tested by low temperature calorimetry (LTC). From the baselines obtained by recording the heat flow of the AAS pastes at different testing temperatures, it is found that no matter in the freezing or melting process, the maximum heat flow-jump increased with the increasing freeze-thaw cycles. From the ice content with temperature change, it is found that the ice in pores mainly melts in the temperature range of -5 °C to 0 °C, and the more freeze-thaw cycles the sample suffered, the more ice melted in this temperature range. The pore structure were coarsened by freezing/thawing, demonstrated by the volume of pores within 8-100 nm increased with the increasing freeze-thaw cycles, and the main increase of pore volume caused by freeze-thaw cycles is in the range of 50-100 nm.