A discussion of the paper “Effect of drying on cement-based materials pore structure as identified by mercury porosimetry—a comparative study between oven-, vacuum-, and freeze-drying” by C. Gallé

The pore structure is a decisive factor for the process efficiency and product quality of freeze dried products. In this work the two-dimensional ice crystal structure was investigated for maltodextrin solutions with different concentrations by a freeze drying microscope. The resulting drying kinetics was investigated for different pore structures. Additionally the three-dimensional pore structure of the freeze dried samples was measured by µ-computed tomography and the pore size distribution was quantified by image analysis techniques. The two- and three-dimensional pore size distributions were compared and linked to the drying kinetics.Keywords: pore size distribution; freeze drying; maltodextrin solution; freeze drying microscope

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Effects of nano-SiO2 and nano-Al2O3 on mechanical and durability properties of cement-based materials: A comparative study

Journal of Building Engineering ◽

10.1016/j.jobe.2020.101936 ◽

2020 ◽

pp. 101936

Author(s):

Ai Zhang ◽

Wencui Yang ◽

Yong Ge ◽

Yuanbo Du ◽

Penghuan Liu

Keyword(s):

Comparative Study ◽

Nano Sio2 ◽

Durability Properties ◽

Cement Based Materials

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Pore Structure Damages in Cement-Based Materials by Mercury Intrusion: A Non-Destructive Assessment by X-Ray Computed Tomography

Materials ◽

10.3390/ma12142220 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2220 ◽

Cited By ~ 8

Author(s):

Xiaohu Wang ◽

Yu Peng ◽

Jiyang Wang ◽

Qiang Zeng

Keyword(s):

Computed Tomography ◽

Pore Structure ◽

High Mass ◽

X Ray ◽

Quantitative Evidence ◽

Mercury Intrusion ◽

Pore Size Distributions ◽

Cement Based Materials ◽

Before And After ◽

X Ray Computed

Mercury intrusion porosimetry (MIP) is questioned for possibly damaging the micro structure of cement-based materials (CBMs), but this theme still has a lack of quantitative evidence. By using X-ray computed tomography (XCT), this study reported an experimental investigation on probing the pore structure damages in paste and mortar samples after a standard MIP test. XCT scans were performed on the samples before and after mercury intrusion. Because of its very high mass attenuation coefficient, mercury can greatly enhance the contrast of XCT images, paving a path to probe the same pores with and without mercury fillings. The paste and mortar showed the different MIP pore size distributions but similar intrusion processes. A grey value inverse for the pores and material skeletons before and after MIP was found. With the features of excellent data reliability and robustness verified by a threshold analysis, the XCT results characterized the surface structure of voids, and diagnosed the pore structure damages in terms of pore volume and size of the paste and mortar samples. The findings of this study deepen the understandings in pore structure damages in CBMs by mercury intrusion, and provide methodological insights in the microstructure characterization of CBMs by XCT.

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