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1

Analysis of the degradation process of sand-lime plasters under the impact of crystallization pressure

Ślusarek Jan, Słomka-Słupik Barbara, Bochen Jerzy

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 2

137--149

EN

A masonry basement wall was heavily dampened due to the lack of waterproofing in the ground contact area. Internal sand-lime wall plaster samples were subjected to chemical, physical and strength tests. The main phases of the damaged plaster were quartz and calcite. A measuring method of the tensile strength of plasters was proposed. A polar-symmetric deformation problem of a thick-walled spherical tank, allowing for the estimation of circumferential stresses in the spherical model was used for the analysis. It was found that the same values of porosity correspond to identical values of circumferential stresses, regardless of the values of the radii of the analyzed model. Thus the purpose of the presented research was to demonstrate that the mentioned dependence applied in the adopted model may be useful for the analysis of problems involving the resistance of internal plaster structure to the expansion caused by crystallization pressure.

2

Wpływ struktury porowatości na odporność na korozję betonu wysokowartościowego zawierającego metakaolin

Philip Nivin, Jędrzejewska Agnieszka, Varughese Abynoah E., James Jomy

Cement Wapno Beton

|

2022

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R. 27, nr 5

302--319

PL

Chociaż beton jest uważany za trwały materiał, środowisko, na które jest narażony, ma duży wpływ na jego trwałość. Trwałość betonu może być zagrożona ze względu na jego porowatość, szczególnie w trudnych warunkach ekspozycji, którymi jest na przykład środowisko morskie. Żelbetowe elementy konstrukcji morskich, do których należą między innymi mosty, nabrzeża i doki, są poddawane różnego rodzaju oddziaływaniom. Należą do nich cykliczne nawilżanie i suszenie, stan pełnego zanurzenia oraz kontakt z chlorkami. Aby poprawić strukturę porów w betonie i wytrzymałość takich konstrukcji, niezbędne jest stosowanie betonu wysokowartościowego. W badaniach przedstawionych w niniejszej pracy, do produkcji betonu wysokowartościowego zastosowano metakaolin [MK], jako częściowy zamiennik cementu. Wyniki tych badań pokazały, że zastosowanie metakaolinu zmniejsza porowatość betonu, a wraz ze spadkiem porowatości znacznie zmniejsza się szybkość procesu korozji. Beton wysokowartościowy zawierający metakaolin badano przez 365 dni, w celu określenia zmian struktury porowatości po długim okresie ekspozycji, z wykorzystaniem metody iCOR® NDT. Metoda ta służy do określania odporności na korozję i rezystywności betonu bogatego w metakaolin, o dużej wytrzymałości, w warunkach symulowanego nawilżania i suszenia, w środowisku wody morskiej, w kilku okresach. Efekt pogorszenia właściwości betonu, spowodowany symulowanym nawilżaniem i suszeniem w środowisku wody morskiej, był również badany dla przyczepności próbek poddanych normalnym i korozyjnym warunkom ekspozycji.

EN

Even though concrete is considered to be durable, the environment to which the concrete is exposed plays an important role in its durability. The durability of concrete is challenged due to its porous nature, which is especially important in harsh exposure conditions such as marine environment. The reinforced concrete elements of marine structures such as bridges, wharves, docks, etc. are subjected to various types of exposures such as wetting and drying action [WDA], fully submerged condition, and in contact with chlorides. To refine the pore structure of concrete and to improve the durability characteristics of such structures, it is essential to use high performance concrete [HPC]. In this study, metakaolin [MK] is used as partial replacement of cement to produce HPC. The use of metakaolin is found to be very effective in reducing the porosity of concrete. As the porosity of concrete decreases, the corrosion rate can be reduced considerably. The durability characteristics of metakaolin-incorporated HPC is studied for 365 days to investigate the changes in its pore structure in long term. The iCOR® NDT method is used to find the corrosion performance and concrete resistivity of high performance metakaolin concrete under a simulated wetting and drying action [WDA] of seawater over several periods. The deterioration effect caused by the simulated WDA of seawater is also studied by considering the bond strength of specimens subjected to normal and corrosive exposure conditions.

3

Effects of early‑age temperature and salt ion corrosion on the macroproperty deterioration of concrete and corresponding micromechanism

Xue Weipei, Fan Hongjun, Liu Xiaoyuan, Shen Lei

Archives of Civil and Mechanical Engineering

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2022

|

Vol. 22, no. 2

art. no. e98, 1--16

EN

This paper experimentally examines variations in the macroscopic properties of concrete under the interaction of early-age temperature and salt ion corrosion and investigates the microscopic mechanism of these variations from the perspective of pore structure and microcracks. The results show a prominent initial defect compaction stage of the compressive stress-strain curves of the specimens under the interaction of two factors, an increase in the number of pores and a high degree of crack development. Accordingly, the peak strength, secant elastic modulus and porosity of the specimens are greatly affected by the interaction between early-age temperature and salt ion corrosion, as reflected by the obvious deterioration trend. Based on a theoretical analysis, the concept of the initial defect strain ratio is proposed, the relationship between the total deformation and two indicators (initial defect deformation and matrix deformation) is clarified, and a constitutive model that reflects the initial defect compaction characteristics is established.

4

Changes in fractal dimension and durability of ultra‑high performance concrete (UHPC) with silica fume content

Luan Congqi, Wang Jingyu, Gao Jinxu, Wang Jinbang, Du Peng, Zhou Zonghui, Huang Yongbo, Du Shuang

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 3

art. no. e123

EN

The combined utilization of silica fume (SF) and steel fiber in UHPC is an inevitable trend to improve its mechanical properties and durability. In this study, the influence of SF dosage on mechanical property, permeability, drying shrinkage as well as the pore structure and fractal dimension (Ds) of UHPC was investigated. Finally, the relationships between the durability of UHPC and the porosity as well as the Ds were revealed and discussed. The results demonstrate that the synergistic effect of SF and fiber increased mechanical properties of UHPC due to the friction and mechanical interlocking of the steel fiber to the fiber-matrix and the adhesion between fiber and paste provided by the silica fume. In addition, incorporating 20% enhanced the mechanical property, decreased the chloride diffusion coefficient, and increased the Ds value. Moreover, increasing Ds value linearly raised compressive strength and drying shrinkage but nonlinearly depressed permeability in UHPC, so Ds can be served as a navel parameter to characterize the permeability and drying shrinkage of UHPC.

5

Petrophysical properties prediction of deep dolomite reservoir considering pore structure

Gui Jinyong, Yin Xingyao, Jianhu Gao, Li Shengjun, Liu Bingyang

Acta Geophysica

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2022

|

Vol. 70, no 4

1507--1518

EN

Prediction of petrophysical properties of deep dolomite reservoir using elastic parameter data is challenging and of great uncertainty. Changes in the petrophysical properties generally induce perturbations in elastic properties. Rock-physics model, which plays a role as a bridge between petrophysical properties and elastic properties, determines the accuracy of inversion for petrophysical properties using elastic properties. Different pore structures lead to variations of rock-physics relationships, and in dolomite reservoir, the influence of pore structure on elastic properties is larger than that of petrophysical properties. We first propose a statistical rock-physics model, in which we consider the effect of pore structure on the nonlinear rockphysical relationship between petrophysical properties and elastic properties of dolomite reservoirs. Then, we propose a Bayesian inversion approach of using elastic properties to predict petrophysical properties and use weight factors to address the difference in accuracy of the input elastic properties in the Bayesian inversion framework. Examples illustrate the proposed approach may produce petrophysical properties of high accuracy for deep dolomite reservoirs.

6

Effect of the ground granulated blast furnaceslag on the pore structure of concrete

Chalid Abdul

Archives of Civil Engineering

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2021

|

Vol. 67, nr 1

203--214

EN

The objective of this study is to analyze effect of ground granulated blast furnace slag (GGBFS) in concrete on the pore structure, this research will contribute to the knowledge regarding the use of GGBFS as a cementitious material in terms of the future reference and potential improvement to the properties of concrete. To this aim, on the one hand a control specimens (CS) and another samples with 40% and 60% of GGBFS as replacement cement with moist cured at 20°C, 27°C, and cured at site. The compressive strength and the Mercury intrusion porosimetry (MIP) test were done. The result indicates that the strength of concrete with GGBFS at early ages tend to be lower in comparison with the CS. However, the GGBFS reaction plays important roles at the later ages. The samples cured at higher temperature produce higher strength value. The total pore volume (TPV) of the concrete use GGBFS decreases with increasing age.

7

Multi parameter logging evaluation of tight sandstone reservoir based on petrophysical experiment

Li Haitao, Deng Shaogui, Xu Feng, Niu Yunfeng, Hu Xufei

Acta Geophysica

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2021

|

Vol. 69, no. 2

429--440

EN

Acoustic, resistivity and nuclear magnetic resonance (NMR) logging are important means of reservoir evaluation. In this paper, the information of pore structure, such as the aspect ratio and the shape, is obtained by rock physical experiments like constant velocity mercury injection and casting thin section. Taking pore structure information as a link, the theoretical relations among acoustic-NMR, acoustic-resistivity and resistivity-NMR of rocks are studied, respectively, based on the diferential equivalent model and fractal theory, and the theoretical derivation results are verifed by AE acoustic emission experiment, rock resistivity experiment and NMR experiment. It is found that there is a power function relationship between the P/S wave velocity and the geometric mean value of NMR T2. Moreover, there are also power function relationships between the slowness of P/S wave and resistivity, and between the value of NMR T2 and the increase rate of resistance. Based on the above relationship, the gas reservoir can be identifed by acoustic-resistivity-NMR multi-parameters in well G of the study area. Compared with the conventional P/S velocity ratio and P-wave slowness intersection method, the separa tion efect of gas and water is more obvious.

8

Prediction of porosity and gas saturation for deep‑buried sandstone reservoirs from seismic data using an improved rock‑physics model

Yaneng Luo, Handong Huang, Morten Jakobsen, Yadi Yang, Jinwei Zhang, Yanjie Cai

Acta Geophysica

|

2019

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Vol. 67, no. 2

557--575

EN

In recent years, many important discoveries have been made in global deep oil and gas exploration, which indicates that deep exploration has gradually become one of the most important areas in current and future hydrocarbon exploration. However, the prediction of deep reservoirs is very challenging due to their low porosity and complex pore structure characteristics caused by the burial depth and diagenesis. Rock physics provides a link between the geologic reservoir parameters and seismic elastic properties and has evolved to become a key tool of quantitative seismic interpretation. Based on the mineral component and pore structure analysis of studied rocks, we propose an improved rock-physics model by introducing a third feldspar-related pore for deep-buried sandstone reservoirs to the traditional Xu–White model. This modelling process consists of three steps: first, rock matrix modelling using time-average equations; second, dry rock modelling using a multipore analytical approximation; and third, fluid-saturated rock modelling using a patchy distribution. It has been used in total porosity estimation, S-wave velocity prediction and rock-physics template establishment. The applicability of the improved rock-physics model is verified by a theoretical quartz-water model test and a real data total porosity estimation compared with the traditional Xu–White model and the density method. Then, a rock-physics template is generated by the improved rock-physics model for porosity and gas saturation prediction using seismic data. This template is carefully calibrated and validated by well-log data at both the well-log scale and seismic scale. Finally, the feasibility of the established rock-physics template for porosity and gas saturation prediction is validated by a deep-buried sandstone reservoir application in the East China Sea.

9

Fabrication Of Porous Ti By Thermal Decomposition And Sintering Of PMMA/TiH2 Powder Compact

Jeon K. Ch., Kim Y. D., Suk M.-J., Oh S.-T.

Archives of Metallurgy and Materials

|

2015

|

Vol. 60, iss. 2B

1375--1377

EN

Porous Ti with controlled pore structure was fabricated by thermal decomposition and sintering process using TiH2 powders and Polymethylmethacrylates (PMMA) beads as pore forming agent. The beads sizes of 8 and 50 μm were used as a template for fabricating the porous Ti. The TiH2 powder compacts with 20 and 70 vol% PMMA were prepared by uniaxial pressing and sintered for 2 h at 1100°C. TGA analysis revealed that the PMMA and TiH2 were thermally decomposed at about 400°C forming pores and at about 600°C into metallic Ti phase. The porosity increased with increase in the amount of PMMA addition. Also, the microstructure observation showed that the pore size and shape were strongly dependent on the PMMA shapes.

10

Mrozoodporność betonów o dużej ciekłości napowietrzonych za pomocą mikrosfer polimerowych

Molendowska A., Wawrzeńczyk J.

Materiały Budowlane

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2011

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nr 10

50-51

11

Pore structure of self-compacting concretes made using different superplasticizers

Gorzelańczyk T., Hoła J.

Archives of Civil and Mechanical Engineering

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2011

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Vol. 11, no 3

611-621

EN

The paper presents the results of investigations into the pore structure of self-compacting concretes made from the same components, except for the added (two most commonly used in building practice) superplasticizers. It is shown that the pore structure depends on the superplasticizer used. Also the results of tests carried out to determine the mechanical properties of the investigated concretes, including their compressive strength and the levels of cracking initiating stress and critical stress (demarcating the particular stages in failure under compression), are presented. It is shown that the properties depend on the pore structure.

PL

W pracy przedstawiono wyniki badań struktury porów kilku betonów samozagęszczonych, wykonanych z użyciem takich samych składników i dwóch najczęściej stosowanych w praktyce superplastyfikatorów. Wykazano, że struktura porów zależy od użytego superplastyfikatora. Zaprezentowano także wyniki badań podstawowych cech mechanicznych badanych betonów, w tym wytrzymałości na ściskanie i poziomów naprężeń inicjujących pękanie i krytycznych rozgraniczających procesy niszczenia pod wpływem obciążeń ściskających. Wykazano, że cechy te zależą od struktury porów.

12

Analiza fraktalna struktury porów w materiałach budowlanych

Konkol J., Prokopski G.

Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

|

2006

|

z. 40 [229]

263-270

PL

W artykule zaproponowano wykorzystanie metody analizy obrazu i parametrów stereologcznych jako uzupełnienie badań wykonanych metodami porozymetrii rtęciowej czy sorpcji. Zaproponowana metoda może być z powodzeniem stosowana w przypadku innych materiałów budowlanych, nie tylko zaczynów, zapraw czy betonów.

EN

In this work we used image analysis to determine stereological and fractal parameters of concrete porous structures. To prepare the images and perform the calculations we used two computer programs: FRAKTAL_Stereolog i FRAKTAL_Wymiar2D. The proposed method of porous structure analysis uses effective instruments to obtain new informations that help distinguish different pores structures.

13

Dynamika płynu w przepuszczalnym ośrodku porowatym o anizotropowej strukturze przestrzeni porów

Cieszko M.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

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2002

|

Z. 53(241)

43-55

PL

Przedmiotem pracy jest modelowanie ruchu płynu w anizotropowej przestrzeni porów nieodkształcalnego szkieletu. Rozważania oparto na nowym makroskopowym modelu nasyconego płynem porowatego ośrodka [3, 4], w którym przepływ płyn u przez szkielet o anizotropowej strukturze przestrzeni porów jest opisywany jako ruch kontinuum materialnego w płaskiej anizotropowej przestrzeni metrycznej (przestrzeni Minkowskiego) zanurzonej w przestrzeni Euklidesa będącej modelem przestrzeni fizycznej. Sformułowano równania bilansu masy i pędu płynu oraz wyprowadzono równania falowe dla zaburzeń o malej amplitudzie w barotropowym nielepkim płynie wypełniającym anizotropową przestrzeń porów. Pokazano, że prędkość płaskich fal w takim ośrodku zależy od kierunku ich propagacji i dla kierunków głównych przestrzeni porów jest odwrotnie proporcjonalna do krętości porów.

EN

The paper describes fluid motion in a rigid porous medium of anisotropic pore space structure. The discussion was based on the new macroscopic model of saturated porous medium (Cieszko [3], [4]) in which fluid flow through porous skeleton of anisotropic pore structure is described as a motion of the material continuum in the plane anisotropic metric space (Minkowski space) immersed in the Euclidean one that is the model of the physical space. The mass and linear momentum balance equations for fluid were derived and the equation for wave propagation in barotropic inviscid fluid filling anisotropic space of pores was obtained. It was shown that the velocity of the plane wave in such a medium depends on the direction of wave propagation and for the principal direction of the pore space is invesely proportional to the tortuosity of pores.

14

Pomiar parametrów struktury porów w betonie napowietrzonym z uwzględnieniem kształtu pustki powietrznej

Załocha D.

Zeszyty Naukowe. Budownictwo / Politechnika Śląska

|

2002

|

z. 95

513-522

PL

W referacie przedstawiono problemy wynikające ze specyfiki przygotowania próbek betonowych do badań zautomatyzowanych struktury porów za pomocą analizatora obrazu. Zaproponowano sposób odpowiedniej filtracji mierzonych obiektów z uwzględnieniem ich kształtu. Zastosowano metody uczenia maszynowego.

EN

In the paper described are problems following from specific concrete sample preparation to automatic measurements of air-voids structure with the help of image analysis. Special filtration of measured object is proposed. Machine learning systems were used.

15

The effect of ozonation on sorption properties of active carbon and its porous structure. Model investigations

Wolborska A., Maryniak K., Perkowski J.

Polish Journal of Chemical Technology

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2002

|

Vol. 4, nr 2

42-46

EN

The ozone-granulated active carbon system (ozone-GAC) is more often introduced in the technological water treatment cycle. The reactivity of ozone towards water pollutants leads to their oxidation and growth of biodegradability, which is well-known and favourable for the operation of a carbon bed. Does ozonation also affect the active carbon itself? Preliminary investigations on the ozonation of water solution of active carbon are presented. The results of the process were determined by analysing the porous structure of initial adsorbents and after their modification. Also the changes in their sorptivity were determined by studies of adsorption equilibrium for model systems of phenol-active carbon. In the investigations carbon types NOR1T ROW 0.8 SUPRA and PK 1-3 were used. The modification of initial adsorbents deteriorated to a small extent the parameters of porous structure such as specific surface, total pore volume and fraction of micropores. As a result of the ozonation, the sorptivity of the tested active carbon to phenol changes. In general, this change does not refer to the monolayer volume. A tendency to weaken the adsorbate-adsorbent relation is observed.

16

Zastosowanie przestrzeni Minkowskiego do modelowania anizotropowej przestrzeni porów przepuszczalnych materiałów porowatych

Cieszko M.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

|

2000

|

Z. 47 (228)

81-90

PL

Przedmiotem pracy jest modelowanie anizotropowej struktury porów przepuszczalnych materiałów porowatych. W pracy zaproponowano nowy makroskopowy model takiego ośrodka, w którym anizotropowa przestrzeń porów przepuszczalnego szkieletu rozważana jest jako anizotropowa, metryczna przestrzeń Minkowskiego zanurzona w przestrzeni Euklidesa będącej modelem przestrzeni fizycznej. W pracy wykorzystano metryki obu przestrzeni, aby zdefiniować podwójne miary elementów linii, powierzchni i objętości. Umożliwiło to wprowadzenie czysto geometrycznych definicji parametrów charakteryzujących anizotropową strukturę porów materiałów porowatych: porowatości objętościowej, krętości porów oraz porowatości powierzchniowej. Pokazano, że izotropowa struktura porów jest charakteryzowana jedynie przez dwa niezależne parametry.

EN

The present paper describes the anisotropic pore structure of permeable porous materials. A new macroscopic model of saturated porous medium is proposed in which a fluid flow through porous skeleton of anisotropic pore structure is considered as a motion of the material continuum in the plane anisotropic metric space (Minkowski space) immersed in Euclidean space. The metrics of both spaces is used to determine the double measures of any line, surface and volume elements. All that made it possible to introduce pure geometrical macroparameters typical for anisotropic pore structure of porous materials, namely: tortuosity, volume and surface porosity. It has been shown that the isotropic pore structure is described only by two independent parameters.

17

Badanie strukturalnych własności materiałów porowatych z zastosowaniem ultradźwięków

Kochański J., Kubik J.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

|

2000

|

Z. 47 (228)

147-154

PL

W pracy przedstawiono analityczno-eksperymentalny sposób wyznaczania dwóch parametrów struktury porów materiału porowatego, tj. przepuszczalności hydrodynamicznej i krętości, bazujący na pomiarze impulsowej, ultradźwiękowej fali wolnej.

EN

The paper presents a combined experimental and analytical method of determination of two porous material structural parameters: permeability and tortuosity. The method is based on ultrasonic studies of wave parameters in water saturated porous materials.