Comparison of Mercury Intrusion Porosimetry and multi-scale X-ray CT on characterizing the microstructure of heat-treated cement mortar

2020 ◽  
Vol 160 ◽  
pp. 110085 ◽  
Author(s):  
Shanbin Xue ◽  
Peng Zhang ◽  
Jiuwen Bao ◽  
Linfeng He ◽  
Yu Hu ◽  
...  
2020 ◽  
Author(s):  
Mariola Marszałek ◽  
Krzysztof Dudek ◽  
Adam Gaweł ◽  
Jerzy Czerny

<p>The presented investigations are focused on a part of the 13<sup>th</sup> century Church of the Holy Trinity Dominicans monastery in Cracow, Poland, and include the wall façade of the 17<sup>th </sup>century Myszkowski chapel. The chapel was probably designed by Santi Gucci Fiorentino and built by his workshop. Southern façade of the chapel is made of Tertiary limestone blocks that make characteristic rusticated wall. Lower part of the façade is covered with cement and the basement is made of irregular fragments of Jurassic limestone and Cretaceous sandstone partly replaced and bound with cement mortar. The façade revealed clear signs of damage ranging from dark gray soiling of the surface, scaling to efflorescences. The last ones – mainly on the border of limestone blocks and the cement in the part of the basement.</p><p>Laboratory tests included mineralogical, chemical and petrophysical analyses. Optical microscopy, scanning electron microscopy (SEM-EDS), micro-Raman spectroscopy and X-ray diffractometry (XRD) were used for analysing materials and deterioration products of the cement render and mortar. The petrophysical properties of the materials have been performed using mercury intrusion porosimetry. The secondary minerals detected include mainly gypsum CaSO<sub>4</sub>·2H<sub>2</sub>O, thenardite Na<sub>2</sub>SO<sub>4</sub>, <sub> </sub>aphthitalite (Na,K)<sub>3</sub>Na(SO<sub>4</sub>)<sub>2</sub>, darapskite, Na<sub>3</sub>(SO<sub>4</sub>)(NO<sub>3</sub>)·H<sub>2</sub>O, nitre KNO<sub>3</sub>, nitratine NaNO<sub>3</sub>, ettringite Ca<sub>6</sub>Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>(OH)<sub>12</sub>·26H<sub>2</sub>O and monosulphite Ca<sub>4</sub>Al<sub>2</sub>O<sub>6</sub>SO<sub>3</sub>·11H<sub>2</sub>O. Lower blocks of the façade covered with cement contain chiefly gypsum, ettringite and monosulphite, cement from the basement – gypsum and nitre; while efflorescences – thenardite, aphthitalite, darapskite, nitre and nitratine. The origin of the salts have been discussed and the differences in their type have been associated with composition of the materials and their physicochemical properties.</p><p>This work has been financially supported by the AGH University of Science and Technology, statutory grant no. 16.16.140.315.</p>


2021 ◽  
Vol 5 (4) ◽  
pp. 148
Author(s):  
Nanxi Dang ◽  
Jin Tao ◽  
Qiang Zeng ◽  
Weijian Zhao

High piezoresistivity of cement-based composites tuned by conductible fillers provides a feasible way to develop self-sensing smart structures and buildings. However, the microstructural mechanisms remain to be properly understood. In the present work, the piezoresistivity of cement mortar with different dosages of graphene nanoplatelets (GNPs) was investigated, and the microstructure was assessed by electron scanning microscopy (SEM) and mercury intrusion porosimetry (MIP). Two surface fractal models were introduced to interpret the MIP data to explore the multi-scale fractal structure of the GNP-modified cement mortars. Results show that the incorporation of GNPs into cement mortar can roughen the fracture surfaces due to the GNPs’ agglomeration. Gauge factor (GF) rises and falls as GNP content increases from 0% to 1% with the optimal piezoresistivity observed at GNP = 0.1% and 0.05%. The GF values of the optimum mortar are over 50 times higher than those of the reference mortar. Fractal dimensions in macro and micro fractal regions change with GNP content. Analysis shows that the fractal dimensions in micro region decrease first and then increase with the increase of GF values. GNPs not only impact the fractal structure of cement mortar, but also alter the tunneling and contact effects that govern the piezoresistivity of composite materials.


Author(s):  
Yuliia Khmurovska ◽  
Petr Štemberk ◽  
Svyatoslav Sikorin ◽  
Jiří Němeček ◽  
Daria Jóźwiak-Niedźwiedzka ◽  
...  

AbstractThe effect of gamma-ray irradiation on cement mortar properties is investigated in this study in order to understand the mechanism behind the strength and stiffness reduction, which may be significant according to the available researches. 60Co irradiation facility with the generating dose rate of 0.1–10 Gy/s and the total activity of 4.4·1015 Bq (120 kCi) was used to perform the irradiation, so that the total observed dose of the irradiated samples reached the values ranging from 12.0 to 15.0 MGy. An identical set of control samples was placed in the same laboratory conditions away from gamma radiation. The results of nanoindentation, X-ray diffraction analysis and mercury intrusion porosimetry of the irradiated and the control samples are shown and explained in detail in this study. The nanoindentation creep compliance and the nanoindentation elastic modulus of the irradiated and the control samples do not show any significant difference. The mineral composition obtained using the X-ray diffraction analysis of the irradiated and the control samples is also similar. The pore structure rearrangement and microcrack occurrence, which were evidenced by the mercury intrusion porosimetry and scanning electron microscopy, led to the porosity increase and may be attributed to the significant decrease of compressive strength.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1823
Author(s):  
Won-Kyung Kim ◽  
Young-Ho Kim ◽  
Gigwon Hong ◽  
Jong-Min Kim ◽  
Jung-Geun Han ◽  
...  

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the cement mortar for each curing day was improved by about 3.7–15.79%, compared to the specimen that used general water, when two concentrations of HNBW were used as the mixing water. The results of mercury intrusion porosimetry and a scanning electron microscope analysis of the cement paste showed that the pore volume of the specimen decreased by about 4.38–10.26%, thereby improving the watertightness when high-concentration HNBW was used. The improvement in strength and watertightness is a result of the reduction of the microbubbles’ particle size, and the increase in the zeta potential and surface tension, which activated the hydration reaction of the cement and accelerated the pozzolanic reaction.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Fengyuan Li ◽  
Chaojie Wang ◽  
Yangyang Xia ◽  
Yanjie Hao ◽  
Peng Zhao ◽  
...  

To determine the mechanism and strength characteristics of solidification of silt by a permeable polyurethane grouting material, the effects of polymer content, soil moisture, and immersion time on the unconfined compressive strength (UCS) of the silt have been studied. The results showed that the permeable polymer grouting material can significantly improve the performance of silt: (1) A higher amount of polymer produced a greater strength in the solidified soil. (2) The strength of the solidified soil increased as the immersion time was increased. (3) Moisture in the soil was not conducive to improving the strength of the solidified soil. The X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) have proven that polyurethane does not react with the silt, but they could improve the strength of the silt through physical action. Mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) were performed to find that polymers can reduce soil porosity, and the addition of polyurethane improved the strength of the silt mainly through adhesion, wrapping, filling, and bridging.


RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 96057-96064 ◽  
Author(s):  
Juliette Merle ◽  
Pascale Sénéchal ◽  
Fabrice Guerton ◽  
Peter Moonen ◽  
Pierre Trinsoutrot ◽  
...  

The objective of this work is to compare three techniques for characterizing the morphology of porous bio-based carbon foam, namely mercury intrusion porosimetry, scanning electron microscopy and X-ray microtomography.


2015 ◽  
Vol 52 (5) ◽  
pp. 656-663 ◽  
Author(s):  
Yaolin Yi ◽  
Liyang Gu ◽  
Songyu Liu ◽  
Anand J. Puppala

This study addresses the use of an industry by-product, carbide slag (CS), to activate another industry by-product, ground granulated blastfurnace slag (GGBS), for soft clay stabilization in comparison to Portland cement (PC). The properties of CS–GGBS stabilized clays were investigated through unconfined compressive strength (UCS) test, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicated that the optimum CS content for the CS–GGBS stabilized clay to yield the highest UCS was 4%–6%, varying slightly with curing age and GGBS content. The UCS of the optimum CS-GGBS stabilized clays was more than twice that of the corresponding PC stabilized clays. The main hydration products detected for the CS–GGBS stabilized clays included calcium silicate hydrates (CSH), calcium aluminate hydrates (CAH), and alumino-ferrite monosulfate (AFm).


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