Study on Permeability of Concrete Fortifications from WW2 Based on Mercury Intrusion Porosimetry

2021 ◽  
Vol 325 ◽  
pp. 162-167
Author(s):  
Jaroslava Zatloukalová ◽  
Jiří Pazderka ◽  
Petr Lukáš ◽  
Pavel Reiterman
Keyword(s):  
Water Transport ◽  
Pore Radius ◽  
Mercury Intrusion Porosimetry ◽  
High Variability ◽  
Porous System ◽  
Material Degradation ◽  
Mercury Intrusion ◽  
Degradation Processes ◽  
Water Transport Properties ◽  
Determining Factor

Quantification of water transport properties of concrete is crucial for prediction of the material degradation processes. In case of 80 years ́ old concrete of fortification structures of former Czechoslovakia, its permeability is the determining factor of the scale of degradation. Mercury intrusion porosimetry was used to characterize the porous system of seven existing bunkers from the defence line ”Pražská čára” and to calculate the permeability using model of Bágel and Živica. Results showed the altered structure of the old concrete, characterized by no notable peaks, which mark the critical pore radius most responsible for water intake. The majority of pores are small micropores, which does not contribute much in the water transport. However, calculated permeability is high enough to be the cause of several degradation processes. The performed program also confirmed high variability of permeability properties between individual structures.

scholarly journals Effect of Hydrogen Nanobubbles on the Mechanical Strength and Watertightness of Cement Mixtures

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1823
Author(s):  
Won-Kyung Kim ◽  
Young-Ho Kim ◽  
Gigwon Hong ◽  
Jong-Min Kim ◽  
Jung-Geun Han ◽  
...  
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Stable State ◽  
Pozzolanic Reaction ◽  
Hydration Reaction ◽  
High Concentration ◽  
Mercury Intrusion ◽  
Electron Microscope Analysis ◽  
Mixing Water ◽  
Cement Mixtures

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.

scholarly journals Nanoscale Pore Structure Characterization and Permeability of Mudrocks and Fine-Grained Sandstones in Coal Reservoirs by Scanning Electron Microscopy, Mercury Intrusion Porosimetry, and Low-Field Nuclear Magnetic Resonance

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Na Zhang ◽  
Fangfang Zhao ◽  
Pingye Guo ◽  
Jiabin Li ◽  
Weili Gong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pore Size ◽  
Mercury Intrusion Porosimetry ◽  
Mercury Intrusion ◽  
Rock Samples ◽  
Fine Grained ◽  
Low Field ◽  
Water Saturated ◽  
Pore Types ◽  
Scanning Electron

Porosity and permeability of two typical sedimentary rocks in coal bearing strata of underground coal mines in China, i.e., mudrocks and fine-grained sandstones, were comprehensively investigated by multiple experimental methods. Measured porosity averages of the helium gas porosity (φg), MIP porosity (φMIP), water porosity (φw), and NMR porosity (φNMR) of the twelve investigated rock samples range from 1.78 to 16.50% and the measured gas permeabilities (Kg) range from 0.0003 to 2.4133 mD. Meanwhile, pore types, pore morphologies, and pore size distributions (PSD) were determined by focused ion beam scanning electron microscopy (FIB-SEM), mercury intrusion porosimetry (MIP), and low-field nuclear magnetic resonance (NMR). FIB-SEM image analyses showed that the mineral matrix pores including interparticle (interP) and intraparticle (intraP) pores with varied morphologies are the dominant pore types of the investigated rock samples while very few organic matter (OM) pores were observed. Results of the MIP and the full water-saturated NMR measurements showed that the PSD curves of the mudrock samples mostly present a unimodal pattern and nanopores with pore diameter less than 0.1 μm are their predominant pore type, while the PSD curves of the fine-grained sandstone samples are featured by a bimodal distribution. Furthermore, comparison of the full water-saturated and irreducible-water-saturated NMR measurements indicated that pores in the mudrocks are solely adsorption pores (normally pore size < 0.1 μm) whereas apart from a fraction of adsorption pores, a large part of the pores in the sandstone sample with relatively high porosity are seepage pores (normally pore size > 0.1 μm). Moreover, the PSD curves of NMR quantitatively converted from the NMR T2 spectra by T2Pc and weighted arithmetic mean (WAM) methods are in good agreement with the PSD curves of MIP. Finally, the applicability of three classic permeability estimation models based on MIP and NMR data to the investigated rock samples was evaluated.

Mechanical and Water Transport Properties of HSC with Different SCMs

2015 ◽  
Vol 824 ◽  
pp. 105-110
Author(s):  
Jaroslava Koťátková ◽  
Dana Koňáková ◽  
Eva Vejmelková ◽  
Pavel Reiterman ◽  
Jamal Akhter Siddique
Keyword(s):  
Transport Properties ◽  
Water Transport ◽  
High Strength Concrete ◽  
High Strength ◽  
Supplementary Cementitious Materials ◽  
Strength Concrete ◽  
Natural Pozzolana ◽  
Study Results ◽  
Crushed Brick ◽  
Water Transport Properties

Pozzolanic materials and their usage in concrete production are nowadays widely spread. Their application as additives is inherent especially for the purpose of high strength concrete. This article deals with evaluation and comparison of the influence of two different supplementary cementitious materials on the properties of high strength concrete: natural pozzolana (NP) and finely crushed brick (FCB). The studied characteristics are basic physical properties with connection to mechanical parameters, and next to this, characterization of water transport. In the scope of this study results revealed better pertinence of finely crushed brick, as the appropriate replacement of cement was found out to be up to 30%, whilst for natural pozzolana only 10% of cement substitution is favourable. The open porosity as the first indicator of both mechanical and water transport properties appeared to be lower in all studied mixtures with FCB than in the case of NP. With increasing ratio of the additive to cement there is significant worsening of mechanical and water transport parameters when NP is involved. The behaviour of mixtures with FCB is better even when high amount of cement is substituted.

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