Assoc. Prof. Daria Jóźwiak-Niedźwiedzka, Ph.D., Dr. Habil., Eng.

Department of Experimental Mechanics (ZMD)
Division of Strain Fields (PPO)
position: assistant professor
telephone: (+48) 22 826 12 81 ext.: 310
room: 331/345/-9
e-mail: djozwiak
personal site: http://bluebox.ippt.pan.pl/~djozwiak/

Doctoral thesis
2005-01-06Przeciwdziałanie niszczeniu powierzchni betonowych spowodowanemu cyklicznym zamrażaniem i odmrażaniem 
supervisor -- Prof. Andrzej Brandt, Ph.D., Dr. Habil., Eng., IPPT PAN
581 
Habilitation thesis
2016-04-20Analiza trwałości betonu na podstawie mikroskopowych obrazów struktury 
Supervision of doctoral theses
1.2017-01-26
co-supervisor
Dąbrowski Mariusz  Wpływ dodatku popiołów lotnych wapiennych na mikrostrukturę i mrozoodporność kompozytów o matrycach cementowych1057
 

Recent publications
1.Żołek N., Ranachowski Z., Ranachowski P., Jóźwiak-Niedźwiedzka D., Kúdela Jr S., Dvorak T., Statistical assessment of the microstructure of barite aggregate from different deposits using x-ray microtomography and optical microscopy, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2017-0104, Vol.62, No.2, pp.697-702, 2017
Abstract:

Two different barite ore (barium sulfate BaSO4) specimens from different localizations were tested and described in this paper. Analysis of the microstructure was performed on polished sections, and on thin sections using X-ray microtomography (micro-CT), and optical microscopy (MO). Microtomography allowed obtaining three-dimensional images of the barite aggregate specimens. In the tomograms, the spatial distribution of the other polluting phases, empty space as well as cracks, pores, and voids – that exceeded ten micrometers of diameter-were possible to visualize. Also, the micro-CT allowed distinguishing between minerals of different density, like SiO2 and BaSO4. Images obtained and analyzed on thin sections with various methods using the optical microscopy in transmitted light delivered additional information on the aggregate microstructure, i.e. allow for estimation of the different kinds of inclusions (like the different density of the minerals) in the investigated specimens. Above methods, which were used in the tests, completed each another in order to supply a set of information on inclusions’ distribution and to present the important differences of the barite aggregate specimens microstructure.

Keywords:

barite ore, barite aggregate, microstructure, optical microscopy, thin sections analysis, X-ray tomography

Affiliations:
Żołek N.-IPPT PAN
Ranachowski Z.-IPPT PAN
Ranachowski P.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Kúdela Jr S.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
Dvorak T.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
2.Jóźwiak-Niedźwiedzka D., Gibas K., Glinicki M.A., PETROGRAPHIC IDENTIFICATION OF REACTIVE MINERALS IN DOMESTIC AGGREGATES AND THEIR CLASSIFICATION ACCORDING TO RILEM AND ASTM RECOMMENDATIONS, Roads and Bridges - Drogi i Mosty, ISSN: 1643-1618, DOI: 10.7409/rabdim.017.015, Vol.16, pp.223-239, 2017
Abstract:

Considering the long-time durability of concrete in road infrastructure it is important to control the threat of expansive reaction between sodium and potassium hydroxides in the pore solution and the reactive minerals present in the aggregate. Petrographic analysis is the basis for the qualification of aggregates to appropriate classes of reactivity according to ASTM C1778 and RILEM recommendations. This paper presents the results of petrographic analyses of thin sections made from twenty different domestic aggregates. The tested crushed aggregates were obtained from bedrock and glacial deposits. The evaluation of the mineral composition of aggregates included identification of deleterious components and determination of the content of reactive forms of silica. This enabled preliminary classification of aggregate in one of the three classes of reactivity according to RILEM. Obtained results provide an initial assessment of potential reactivity of aggregates and can assist in making decisions to undertake further accelerated or long-term laboratory testing or to modify the concrete mix design.

Keywords:

aggregate, alkali-aggregate reaction (AAR), petrographic analysis, reactive minerals, thin sections

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
Glinicki M.A.-IPPT PAN
3.Schabowicz K., Ranachowski Z., Jóźwiak-Niedźwiedzka D., Radzik Ł., Kúdela Jr S., Dvorak T., Application of X-ray microtomography to quality assessment of fibre cement boards, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2016.02.035, Vol.110, pp.182-188, 2016
Abstract:

In this paper a method of X-ray microtomography (micro-CT) was employed for a direct insight into a microstructure of fibre cement boards of different quality. Four specimens were subjects of examination. Two parameters were determined to characterize the level of compaction of fibres in concrete matrix: mean-square displacement of migrating virtual particles after 500,000 of time steps and a diffusive tortuosity. The results of the investigation had revealed that fibre cement boards differing in density produce different images after processing with micro-CT method. The effect of microstructure tightening due to saturation using dying agent was also detectable.

Keywords:

Fibre cement boards, Delamination of fibres, Computational modelling, X-ray microtomography

Affiliations:
Schabowicz K.-other affiliation
Ranachowski Z.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Radzik Ł.-other affiliation
Kúdela Jr S.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
Dvorak T.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
4.Dąbrowski M., Glinicki M.A., Gibas K., Jóźwiak-Niedźwiedzka D., Effects of calcareous fly ash in blended cements on chloride ions migration and strength of air entrained concrete, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2016.08.115, Vol.126, pp.1044-1053, 2016
Abstract:

The influence of blended cements containing calcareous fly ash (W) on the strength and permeability of air entrained concrete was studied. Moderately active calcareous fly ash of CaO content of 26% and loss on ignition of 2%, obtained from lignite fired power station in Poland, was selected. Ternary cement compositions including siliceous fly ash (V) and ground granulated blast furnace slag (S) were also studied. Air void analysis in hardened concrete was used to evaluate the effectiveness of air entraining process. Pore size distribution was characterized by mercury intrusion porosimetry (MIP). The presence of calcareous fly ash in cement resulted in a moderate increase in the compressive strength of concrete and an increase of the category of resistance to chloride ion migration. Test results revealed a linear relationship between the capillary porosity measured by MIP and the chloride migration coefficient (Dnssm). The permeability was lower for increased clinker replacement level which was due to formation of smaller diameters of the capillary pores.

Keywords:

Air entrained concrete, Air void characteristics, Calcareous fly ash, Chloride ion migration, Multicomponent cements, Pore size distribution, Strength

Affiliations:
Dąbrowski M.-IPPT PAN
Glinicki M.A.-IPPT PAN
Gibas K.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
5.Jóźwiak-Niedźwiedzka D., Jaskulski R., Glinicki M.A., Application of Image Analysis to Identify Quartz Grains in Heavy Aggregates Susceptible to ASR in Radiation Shielding Concrete, Materials, ISSN: 1996-1944, DOI: 10.3390/ma9040224, Vol.9, No.4, pp.224-1-14, 2016
Abstract:

Alkali-silica reaction (ASR) is considered as a potential aging-related degradation phenomenon that might impair the durability of concrete in nuclear containments. The objective of this paper is the application of digital analysis of microscopic images to identify the content and size of quartz grains in heavy mineral aggregates. The range of investigation covered magnetite and hematite aggregates, known as good absorbers of gamma radiation. Image acquisition was performed using thin sections observed in transmitted cross-polarized light with λ plate. Image processing, consisting of identification of ferrum oxide and epoxy resin, and the subsequent application of a set of filtering operations resulted in an adequate image reduction allowing the grain size analysis. Quartz grains were classified according to their mean diameter so as to identify the reactive range. Accelerated mortar bar tests were performed to evaluate the ASR potential of the aggregates. The SiO2 content in the heavyweight aggregates determined using the image analysis of thin sections was similar to XRF test result. The content of reactive quartz hematite was 2.7%, suggesting that it would be prone to ASR. The expansion test, according to ASTM C1260, confirmed the prediction obtained using the digital image analysis.

Keywords:

alkali-silica reaction, grain size, heavyweight aggregate, image analysis, radiation shielding concrete, reactive aggregate, quartz

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Jaskulski R.-IPPT PAN
Glinicki M.A.-IPPT PAN
6.Glinicki M.A., Jóźwiak-Niedźwiedzka D., Gibas K., Dąbrowski M., Influence of Blended Cements with Calcareous Fly Ash on Chloride Ion Migration and Carbonation Resistance of Concrete for Durable Structures, Materials, ISSN: 1996-1944, DOI: 10.3390/ma9010018, Vol.9, No.1 (Special Issue: Utilisation of By-Product Materials in Concrete), pp.18-1-15, 2016
Abstract:

The objective of this paper is to examine the possible use of new blended cements containing calcareous fly ash in structural concrete, potentially adequate for structural elements of nuclear power plants. The investigation included five new cements made with different contents of non-clinker constituents: calcareous fly ash, siliceous fly ash, ground granulated blastfurnace slag, and a reference cement—ordinary Portland cement. The influence of innovative cements on the resistance of concrete to chloride and carbonation exposure was studied. Additionally, an evaluation of the microstructure was performed using optical microscopy on concrete thin sections. Test results revealed a substantial improvement of the resistance to chloride ion penetration into concrete containing blended cements. The resistance was higher for increased clinker replacement levels and increased with curing time. However, concrete made with blended cements exhibited higher depth of carbonation than the Portland cement concrete, except the Portland-fly ash cement with 14.3% of calcareous fly ash. The thin sections analysis confirmed the values of the carbonation depth obtained from the phenolphthalein test. Test results indicate the possible range of application for new cements containing calcareous fly ash.

Keywords:

blended cements, calcareous fly ash, chloride migration, carbonation, durability, nuclear shielding concrete, thin sections

Affiliations:
Glinicki M.A.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
Dąbrowski M.-IPPT PAN
7.Baran T., Glinicki M.A., Jóźwiak-Niedźwiedzka D., The properties of special cements for shielding constructions in nuclear power plants/Właściwości cementów specjalnych przeznaczonych do betonu w konstrukcjach osłonowych elektrowni jądrowych, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.21, No.4, pp.207-216, 2016
Abstract:

The results of studies of concretes from the special cements, destined to the production of shields against the radiation. The study included Portland cement, Portland fly ash cement, and cements with different content of granulated blastfurnace slag. The application of special cements decreased the possibility of ASR occurrence. CEM I 42.5N LH/SR3/NA and CEM III/A 42.5N LH/HSR/NA usage in heavy concrete of gravity in the range of 3200-3600 kg/m3, the compressive strength was in the range of 45-62 MPa and 62-81 MPa after 28 and 90 days, respectively. The comparison of the effect of CEM III/A 42,5N LH/HSR/NA usage instead of CEM I 42,5N LH/SR3/NA for heavy concrete production the systematic decrease of the rate of water absorption, decrease of coeffi cient of chloride ions diffusion, but increased the carbonation rate, was shown.

Keywords:

special cements, concrete shields

Affiliations:
Baran T.-Institute of Ceramics and Building Materials (PL)
Glinicki M.A.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
8.Jóźwiak-Niedźwiedzka D., Brandt A., Gibas K., Ocena możliwości wystąpienia reakcji alkalicznej w betonach osłonowych z kruszywami specjalnymi, Journal of Civil Engineering, Environment and Architecture, ISSN: 2300-5130, DOI: 10.7862/rb.2016.15, Vol.XXXIII, No.63 (1/I/2016), pp.133-140, 2016
Abstract:

Możliwość wystąpienia reakcji alkalicznej wodorotlenków sodu i potasu (Alkali Silica Reaction, ASR) w betonowych osłonach reaktorów wymaga szczególnej ostrożności przy doborze składników betonów do realizacji programu energii jądrowej w Polsce. Uszkodzenia osłon reaktorów w USA i w Belgii wskazują kierunki niezbędnych badań, [1-3]. W badaniach przedstawionych w artykule zastosowano kruszywa o dużej gęstości (osłabianie promieniowania gamma): magnetytowe, barytowe oraz hematytowe oraz kruszywo o wysokiej zawartości wody związanej (absorpcja promieniowania neutronowego) – kruszywo serpentynitowe. Przeprowadzono badania mikroskopowe kruszyw na cienkich szlifach w celu identyfikacji potencjalnie szkodliwych minerałów z uwagi na zagrożenie ASR, oraz przyspieszone i długotrwałe badania w celu określenia potencjalnej reaktywności alkalicznej tych kruszyw. Wyniki badań wykluczyły możliwość stosowania kruszywa hematytowego do betonów osłonowych. Wyniki badań odnośnie do wykorzystania dostępnych kruszyw specjalnych tworzą podstawy projektowania bezpiecznych osłon w warunkach krajowych

Keywords:

reakcja krzemionki z wodorotlenkami sodu i potasu (ASR), ekspansja, beton osłonowy, kruszywo specjalne

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Brandt A.-IPPT PAN
Gibas K.-IPPT PAN
9.Ranachowski Z., Jóźwiak-Niedźwiedzka D., Ranachowski P., Dąbrowski M., Kúdela Jr S., Dvorak T., The determination of diffusive tortuosity in concrete specimens using X-ray microtomography, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2015-0140, Vol.60, No.2, pp.1115-1119, 2015
Abstract:

The paper presents a method of pore connectivity analysis applied to specimens of cement based composites differing in water to cement ratio. The method employed X-ray microtomography (micro-CT). Microtomography supplied digitized three-dimensional radiographs of small concrete specimens. The data derived from the radiographs were applied as an input into the application based on the algorithm called ‘random walk simulation’. As the result a parameter called diffusive tortuosity was established and compared with estimated porosity of examined specimens.

Artykuł prezentuje metodę wyznaczania parametru charakteryzującego intensywność połączeń mikroporów w zastosowaniu do próbek kompozytów z matrycą cementową, różniących się stosunkiem wodnocementowym. Metoda bazuje na wynikach badań z zastosowaniem mikrotomografii rentgenowskiej. Analizowano zdigitizowane zestawy danych, opisujące trójwymiarową reprezentację mikrostruktury niewielkich próbek wykonanych z betonu. Przygotowane w ten sposób skany mikrostruktury zastosowano jako dane wejściowe wprowadzone do oprogramowania wykorzystujacego algorytm ‘przypadkowo migrujących cząstek wirtualnych’. W ten sposób wyznaczono parametr mikrostruktury znany jako krętość dyfuzyjna. Parametr ten porównano z porowatością obserwowaną wyznaczoną dla zbadanych próbek przy wykorzystaniu analizy jasności voxeli w analizowanych próbkach.

Keywords:

X-ray tomography, concrete microstructure, diffusive tortuosity

Affiliations:
Ranachowski Z.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Ranachowski P.-IPPT PAN
Dąbrowski M.-IPPT PAN
Kúdela Jr S.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
Dvorak T.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
10.Jóźwiak-Niedźwiedzka D., Microscopic Observations of Self-Healing Products in Calcareous Fly Ash Mortars, MICROSCOPY RESEARCH AND TECHNIQUE, ISSN: 1059-910X, DOI: 10.1002/jemt.22440, Vol.78, pp.22-29, 2015
Abstract:

The results of microstructural characterization of mortars containing fly ash class C (High Calcium Fly Ash) from combustion of lignite are presented. The evaluation of the microstructure was performed using scanning electron microscope, optical, and confocal microscope. The tested beams were bent till the crack and microcracks opening, which were healed during the different curing time. The results showed that the replacement of cement with fly ash class C influenced the process of crack healing. The addition of HCFA, at both 30% and 60%, speeds up the self-healing process in cracks and particularly in micro-cracks. In the research, the completely filling up of the cracks by new phases has not been observed, only the beginning of such process has been noticed.

Keywords:

self-healing, cement matrix, stereomicroscope, SEM-EDX analysis

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
11.Ranachowski Z., Jóźwiak-Niedźwiedzka D., Ranachowski P., Rejmund F., Dąbrowski M., Kúdela Jr S., Dvorak T., Application of X-ray microtomography and optical microscopy to determine the microstructure of concrete penetrated by carbon dioxide, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.2478/amm-2014-0245, Vol.59, No.4, pp.1451-1457, 2014
Abstract:

In the paper two advanced methods for testing cement based composites are described and compared. These are X-ray microtomography and optical microscopy. Microtomography supplies three-dimensional images of small concrete specimens. In the tomograms all cracks, pores and other voids and inclusions, that exceed a few micrometers, are shown. Such visualisation can become a valuable tool for analysis of the basic material properties. Images obtained on thin sections and analysed with various methods on optical microscopes supply additional information on material microstructure that cannot be obtained in tomograms. For example it is relatively easy to determine zone penetrated by CO2 ingress. These two methods, presented on examples of tests, complete each another in order to supply a set of information on composition and defects of tested composite materials.

Keywords:

cement matrix composites, concrete deterioration, X-ray tomography, microscopic analysis, concrete microstructure

Affiliations:
Ranachowski Z.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Ranachowski P.-IPPT PAN
Rejmund F.-IPPT PAN
Dąbrowski M.-IPPT PAN
Kúdela Jr S.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
Dvorak T.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
12.Jóźwiak-Niedźwiedzka D., Brandt A.M., Gibas K., Denis P., The alkali - aggregate reaction hazard in the case of barite concretes, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.19, No.4, pp.234-242, 2014
Abstract:

Concretes for the shields against ionizing radiation should be executed with particular care to satisfy all requirements, not only effective attenuation of different radiation but also sufficient durability. In the paper fundamental problems are presented that are related with designing of such protective concretes in order to avoid alkali-aggregate reaction. The results of preliminary investigations are presented that indicate how to select barite aggregate and to define composition of concrete mix. Present knowledge in that area of materials engineering should be completed before initiation of construction of nuclear power stations at industrial scale in Poland.

Keywords:

Alkali Aggregate Reaction (AAR), heavy aggregate, ionizing radiation

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Brandt A.M.-IPPT PAN
Gibas K.-IPPT PAN
Denis P.-IPPT PAN
13.Brandt A.M., Jóźwiak-Niedźwiedzka D., The influence of ionizing radiation on microstructure and properties of concrete shields – a review, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.18, No.4, pp.216-237, 2013
Abstract:

Concrete is used universally as a basic material for shields against ionizing radiation in various buildings related to nuclear energy plants and for other applications of fission materials, e.g. for material testing, therapeutic treatment installations and radioactive materials deposits. In order to fulfil their structural functions, concrete containment walls should have sufficient durability and the control of the ageing of concrete is necessary in all conditions of their functioning. Apart from climatic actions there are serious problems related to the influence of radiation on concrete microstructure and properties during many years of exploitation, particularly in the case of high doses of irradiation with neutrons and rayons gamma (γ).

Keywords:

concrete shields, nuclear power plant, special aggregate, ionizing radiation

Affiliations:
Brandt A.M.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
14.Jóźwiak-Niedźwiedzka D., Sobczak M., Gibas K., Carbonation of concretes containing calcareous fly ashes, Roads and Bridges - Drogi i Mosty, ISSN: 1643-1618, DOI: 10.7409/rabdim.013.016, Vol.12, No.2, pp.223-236, 2013
Abstract:

The purpose of this research was to determine the carbonation depths in concrete containing calcareous fly ash. Eleven concrete mixes with the same water-binder ratio w/b and with different amounts of calcareous fly ash have been prepared in laboratory. In the test series I the mixes were produced with five blended cements containing different amounts of the following supplementary cementitious materials: calcareous fly ash, siliceous fly ash and granulated blast furnace slag. The second test series was produced with calcareous fly ash replacing 30% of the cement by weight. The maximum depth of carbonation in concrete was determined using the phenolphthalein method. The progress of the carbonation front was established by analysing polished thin sections of concrete under a polarizing microscope in transmitted light. The most resistant to carbonation was the concrete containing, beside clinker, 14.3% of calcareous fly ash as a cementitious material. The specimens of concrete containing different amounts of calcareous fly ash were compared and no significant variations were found both in the rate and depth of carbonation. On the other hand, the rate of advancement of carbonation front was higher in concrete containing calcareous fly ash as compared to the reference concrete without admixtures.

Keywords:

blended cements, calcareous fly ash, carbonation, particle size separation of fly ash

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Sobczak M.-IPPT PAN
Gibas K.-IPPT PAN
15.Marks M., Jóźwiak-Niedźwiedzka D., Glinicki M.A., Olek J., Marks M., Assessment of Scaling Durability of Concrete with CFBC Ash by Automatic Classification Rules, JOURNAL OF MATERIALS IN CIVIL ENGINEERING, ISSN: 0899-1561, DOI: 10.1061/(ASCE)MT.1943-5533.0000464, Vol.24, No.7, pp.860-867, 2012
Abstract:

The objective of this investigation was to develop rules for automatic assessment of concrete quality by using selected artificial intelligence methods based on machine learning. The range of tested materials included concrete containing nonstandard waste material—the solid residue from coal combustion in circulating fluidized bed combustion boilers (CFBC ash) used as an additive. Performed experimental tests on the surface scaling resistance provided data for learning and verification of rules discovered by machine learning techniques. It has been found that machine learning is a tool that can be applied to classify concrete durability. The rules generated by computer programs AQ21 and WEKA by using the J48 algorithm provided a means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials resistant or not resistant to the surface scaling.

Keywords:

Machine learning, Automatic classification rules, Database, Concrete durability, Scaling resistance, Circulated fluidized bed combustion fly ash (CFBC fly ash)

Affiliations:
Marks M.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Glinicki M.A.-IPPT PAN
Olek J.-Purdue University (US)
Marks M.-IPPT PAN
16.Marks M., Jóźwiak-Niedźwiedzka D., Glinicki M.A., Automatic categorization of chloride migration into concrete modified with CFBC ash, COMPUTERS AND CONCRETE, ISSN: 1598-8198, DOI: 10.12989/cac.2012.9.5.375, Vol.9, No.5, pp.393-405, 2012
Abstract:

The objective of this investigation was to develop rules for automatic categorization of concrete quality using selected artificial intelligence methods based on machine learning. The range of tested materials included concrete containing a new waste material - solid residue from coal combustion in fluidized bed boilers (CFBC fly ash) used as additive. The rapid chloride permeability test - Nordtest Method BUILD 492 method was used for determining chloride ions penetration in concrete. Performed experimental tests on obtained chloride migration provided data for learning and testing of rules discovered by machine learning techniques. It has been found that machine learning is a tool which can be applied to determine concrete durability. The rules generated by computer programs AQ21 and WEKA using J48 algorithm provided means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials of good and acceptable resistance to chloride penetration.

Keywords:

concrete durability, chloride ions migration, circulated fluidized bed combustion fly ash (cfbc fly ash), machine learning, classification rules, database

Affiliations:
Marks M.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Glinicki M.A.-IPPT PAN
17.Jain J., Janusz A., Olek J., Jóźwiak-Niedźwiedzka D., Effects of Deicing Salt Solutions on Physical Properties of Pavement Concretes, TRANSPORTATION RESEARCH RECORD, ISSN: 0361-1981, DOI: 10.3141/2290-09, Vol.2290, pp.69-75, 2012
Abstract:

Salt solutions are used on pavement surfaces during wintry weather events to guarantee safe driving conditions. In addition to sodium chloride (NaCl) which continues to be traditionally used as deicer, the usage of solutions of calcium chloride (CaCl2) and magnesium chloride (MgCl2) is on the increase due to need provide a more consistent ice and snow control and thus ensure safety of the travelling public. This paper assesses the effects of three different salt solutions (NaCl, CaCl2, and MgCl2) on several physical and mechanical properties of pavement concretes. These deicing solutions were used under simulated wetting-drying (WD) and freezing-thawing (FT) exposure regimes with total ion concentration of the deicers was 10.5 molal for WD exposure and 5.5 molal for FT exposure.
Two types of concretes were used in the study; the ordinary portland cement concrete and the fly ash concrete (20% of cement replacement by mass). The prismatic and cylindrical specimens were used to monitor physical changes due to these exposure regimes. The physical changes of cylindrical specimens subjected to the WD regime were monitored by taking ultrasonic pulse velocity (UPV) measurements after every 2 weeks of exposure and crushing these cylinders at the end to obtain the compressive strength. The effects on prismatic specimens were monitored by measuring mass and resonant frequencies after every 2 weeks of exposure and using these data to calculate changes in the relative dynamic modulus of elasticity (RDME). The test results obtained from the RDME and UPV measurements, combined with visual observations were used to assess the effects of deicers on concretes. It was observed that CaCl2 solution is more harmful as compared to MgCl2 solution for both plain and fly ash modified concretes.

Keywords:

Deicing Salt Solutions, Pavement Concretes

Affiliations:
Jain J.-Purdue University (US)
Janusz A.-Purdue University (US)
Olek J.-Purdue University (US)
Jóźwiak-Niedźwiedzka D.-IPPT PAN
18.Ranachowski Z., Jóźwiak-Niedźwiedzka D., Brandt A.M., Dębowski T., Application of Acoustic Emission Method to Determine Critical Stress in Fibre Reinforced Mortar Beams, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.37, No.3, pp.261-268, 2012
Abstract:

The objective of this investigation was to test the effectiveness of the Acoustic Emission (AE) measurements in determining the critical stresses during four-point bending of mortar beams. Within the measuring procedure the parameter σcr/σ300 was calculated and analysed. Additionally, the influence of cement replacement by high calcium fly ash (HCFA) on the process of crack healing was discussed. Mortar beams with different content of HCFA and reinforced by steel microfibres were prepared for tests. After curing in standard conditions the beams were subjected to four-point bending test in order to introduce the pre-cracking. Thereafter the beams were cured in the lime water and loaded after 56 and 112 days in the same way as for the first time. Additionally the microstructure of mortars was studied in a stereo optical microscope as well in an electron scanning microscope including the Energy Dispersive X-ray analysis (EDX). The results of microstructural characterization of mortar containing HCFA from lignite combustion are presented. The applied load level slightly exceeded the critical stress, producing intense crack growth processes however did not significant affected the load capacity of the beams. During the consecutive loading the decreasing tendency of σcr/σ300 ratio was noted. The obtained results confirm that the latter parameter can be applied as a measure of the composite degradation level for the elements carrying the repeated loads of amplitude close to the critical stress of the structure and also that the cement replacement with HCFA influences the process of crack healing.

Keywords:

critical stress, Acoustic Emission, microcracking, self-healing, concrete microstructure, fly ash

Affiliations:
Ranachowski Z.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Brandt A.M.-IPPT PAN
Dębowski T.-IPPT PAN
19.Jóźwiak-Niedźwiedzka D., Brandt A.M., Ranachowski Z., Self-healing of cracks in fibre reinfored mortar beams made with high calcium fly ash, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.XVII/LXXIX, No.1, pp.38-49, 2012
Abstract:

Mortar beams were cast with various content of high calcium fly ash as a partial replacement of Portland cement. The results of microstructural characterization of mortar containing fly ash class C (High Calcium Fly Ash – HCFA) from lignite combustion are presented. The evaluation of the microstructure was performed using SEM and optical microscopy. At the age of 28 days the beams were subjected to 4-point bending until opening of a system of microcracks and cracks. Then, the beams were cured in lime water for 56 and 112 days after precracking and again subjected to loading. The results in a form of partial self-healing were recorded with load-deflection curves and using optical methods. The results show the percentage of replacement of cement by fly ash influenced the process of crack healing.

Keywords:

Microcracking, Self-healing, Microstructure, Fly Ash

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Brandt A.M.-IPPT PAN
Ranachowski Z.-IPPT PAN
20.Jóźwiak-Niedźwiedzka D., Estimation of chloride migration coefficient in air-entrained concretes containing fluidized bed combustion fly ash, ARCHIVES OF CIVIL ENGINEERING, ISSN: 1230-2945, Vol.LVIII, No.1, pp.25-38, 2012
Abstract:

The objective of this investigation was comparing the penetration of chloride ions in ordinary and air-entrained concretes containing a waste material Fluidized Bed Combustion Fly Ash (FBCFA). All concretes were tested with 15% and 30% cement replacement by FBCFA, with the same water-binder ratio of 0.45. Two kinds of fly ash coming from fluid bed combustion in two power plants in Poland have been used.
In this study the rapid chloride permeability test - Nordtest Method BUILD 492 method - was used. The microstructure of the concrete was analyzed on thin polished sections and the measurement of air voids sizes and their distribution, using digital image analysis, was carried on according to PN-EN 480-11:2008.
Obtained results have shown a significant influence of partial cement replacement by FBCFA on the chloride ions movements in concrete. It has been found that this kind of addition reduced considerably the chloride ion penetration. The influence of air entrainment on the chloride diffusion coefficients was also measured and it was shown that application of air-entraining admixture for concretes with FBCFA reduce the chloride diffusion coefficient but it should be used with caution.

Keywords:

Fluidized Bed Combustion Fly Ash (FBCFA), Pore Size Distribution, Chloride Permeability, Concrete, Durability

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
21.Jóźwiak-Niedźwiedzka D., Mikrostruktura i wytrzymałość zapraw z cementów wieloskładnikowych zawierających popiół lotny wapienny, ZESZYTY NAUKOWE POLITECHNIKI RZESZOWSKIEJ, SERIA: BUDOWNICTWO I INŻYNIERIA ŚRODOWISKA, ISSN: 0209-2646, Vol.59 (3/12/III), No.283, pp.205-212, 2012
Abstract:

Tematem referatu jest ocena mikrostruktury, mikrotwardości i wczesnej wytrzymałości zapraw wykonanych z cementów wieloskładnikowych, zawierających różne ilości dodatku popiołu lotnego wapniowego. Zakres badań objął prototypowe cementy CEM II i CEM V wykonane w skali laboratoryjnej. Do badań mikrostruktury zapraw i składników wyjściowych zastosowano mikroskopię optyczną z wykorzystaniem cyfrowej analizy obrazu, mikroskopię skaningową z mikrosondą i metodę mikroindentacji. Wytrzymałość zapraw z cementów wieloskładnikowych z udziałem popiołów wapiennych po 28 dniach twardnienia oznaczona zgodnie z normą była niższa od zaprawy przyjętej za wzorzec, wykonanej z cementu CEM I bez dodatków. Obniżenie wytrzymałości w stosunku do wzorca zawierało się w granicach od 11 do 41% i było wyraźnie zależne od ilości dodatków popiołu lotnego wapiennego, krzemionkowego czy żużla wielkopiecowego. Wzrost ilości dodatku powodował obniżenie wytrzymałości. W mikrostrukturze matrycy cementowych zapraw badanych techniką SEM stwierdzono, że tworzące ją uwodnione krzemiany wapnia typu C-S-H mają we wszystkich zaprawach zbliżona budowę tzw. plastra miodu, wśród których są obecne heksagonalne kryształy portlandytu i relikty nieuwodnionych ziarn cementu oraz ziarna kuliste, pochodzące z dodatku popiołu.

Keywords:

mikrostruktura, popiół lotny wapienny, cementy wieloskładnikowe, wytrzymałość, SEM, mikroskopia optyczna

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
22.Brandt A.M., Jóźwiak-Niedźwiedzka D., Diagnosis of Concrete Quality by Structural Analysis, Advances in Civil Engineering Materials, Vol.1, No.1, pp.1-21, 2012
Abstract:

In this review paper the structure of concrete investigated as a composite material is analyzed on different levels from the viewpoint of its diagnosis. The diagnosis of a complex structure of concrete should cover identification and estimation of existing damages and possible failures. The aim is to ensure adequate durability and high quality of concrete in infrastructure works. The most effective methods that are actually available are shortly described. Beside various non destructive techniques, the optical and scanning electron microscopy that is applied on specimens representing material used in a diagnosed structure, are shortly described. The importance of quantitative results of material analysis and of image processing is stressed. On the basis of a thorough structural analysis of the concrete treated as a multicomponent material it is possible to determine its quality, to check correct execution of the designed diverse composition and to verify used components. All these data form necessary basis for a diagnosis of concrete quality and conformity with requirements. The review is partly based on research developed and realized at IPPT PAN during past several years in the scope of concrete treated as a structural composite material.

Keywords:

Concrete, Durability, Image analysis, Microstructure

Affiliations:
Brandt A.M.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
23.Jóźwiak-Niedźwiedzka D., Gibas K., Glinicki M.A., Nowowiejski G., Wpływ dodatku popiołu lotnego wapiennego na przepuszczalność betonów w odniesieniu do mediów agresywnych, DROGI I MOSTY, ISSN: 1643-1618, Vol.3, pp.39-61, 2011
Abstract:

Celem przeprowadzonych badań była ocena przepuszczalności betonu zawierającego popiół lotny wapienny pochodzący ze spalania węgla brunatnego, w stanie surowym i po dodatkowym domieleniu. W badaniach skoncentrowano się na określeniu wpływu ilości popiołu jako dodatku do betonu na wnikanie mediów agresywnych. Określono podstawowe właściwości mieszanki betonowej oraz wytrzymałość na ściskanie. Oznaczono współczynnik migracji jonów chlorkowych przy nieustalonym ich przepływie, głębokość penetracji wody pod ciśnieniem oraz współczynnik gazoprzepuszczalności betonu. Mikrostrukturę badanych betonów przeanalizowano na cienkich płytkach w mikroskopie polaryzacyjnym do światła przechodzącego. Stwierdzono, że zastąpienie cementu przez dodatek popiołów lotnych wapiennych do betonu w ilości 15% lub 30% przy w / s =0,55 powoduje poprawę ich wodo- i gazoszczelności, z tą jednak różnicą, że do zmniejszenia gazoprzepuszczalności betonu odpowiedniejsze jest stosowanie popiołów domielonych. Niższe wartości współczynnika migracji jonów chlorkowych otrzymano w betonach zawierających popiół lotny wapienny, wzrost w / s zwiększył przenikalność jonów chlorkowych. Analiza obrazów na cienkich szlifach betonowych wykazała, że w miarę wzrostu zawartości popiołu w betonie wzrasta również ilość niespalonych cząstek węgla w matrycy, których wielkość jest zależna od czasu mielenia popiołu

Keywords:

gazoprzepuszczalność, migracja chlorków, mikrostruktura, popiół lotny wapienny, wodoprzepuszczalność

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
Glinicki M.A.-IPPT PAN
Nowowiejski G.-IPPT PAN
24.Kosior-Kazberuk M., Jóźwiak-Niedźwiedzka D., Influence of fly ash from co-conbustion of coal and biomass on scaling resistance of concrete, ARCHIVES OF CIVIL ENGINEERING, ISSN: 1230-2945, Vol.56, No.3, pp.239-254, 2010
Abstract:

Industrial utilization of fly ash from various kinds of fuel plays an important role in the environmentally clean and cost effective power generation. The primary market for fly ash utilization is as a pozzolanic addition in concrete production. The paper concerns the concretes containing fly ash called Fly Ash from Biomass (FAB) from co-combustion of hard coal and wood biomass (wood chips). Characterization of the fly ash was carried on by means of X-ray diffractometry and E-SEM/EDS analysis. The results of laboratory studies undertaken to evaluate the influence of FAB on concrete resistance to surface scaling due to cyclic freezing and thawing in the presence of NaCl solution were presented. The tests were carried out for concretes containing up to 25% of fly ash related to cement mass. Additionally, the microstructure of air-voids was described.
It was concluded that the FAB has significant effect on concrete freeze/thaw durability. The replacement of cement by fly ash from co-combustion progressively transformed the concrete microstructure into less resistant against freeze/thaw cycles and excessive dosage (over 15%) may dangerously increase scaling.

Keywords:

concrete, durability, fly ash from co-combustion of coal and biomass, scaling resistance, microstructure

Affiliations:
Kosior-Kazberuk M.-other affiliation
Jóźwiak-Niedźwiedzka D.-IPPT PAN
25.Jóźwiak-Niedźwiedzka D., Tucholski Z., Wiadukt żelbetowy z początków XX wieku - analiza mikrostruktury stuletniego betonu, DROGI I MOSTY, ISSN: 1643-1618, Vol.3, pp.23-37, 2010
Abstract:

W artykule opisano historię wiaduktu Kolei Kaliskiej a także stan zachowania konstrukcji. Omówiono aktualny stanu jakości betonu z wiaduktu sklepionego parabolicznego Drogi Żelaznej Warszawsko-Kaliskiej – najprawdopodobniej jednej z dwóch najstarszych budowli inżynierskich o konstrukcji betonowej na terenie Warszawy. Zamieszczono opis przygotowywania cienkich szlifów betonowych oraz przedstawiono wyniki analizy cienkich szlifów uzyskane za pomocą mikroskopu optycznego do obserwacji mikrostruktury betonu w świetle spolaryzowanym i w świetle ultrafioletowym. Scharakteryzowano rodzaj i wielkość kruszywa (analiza petrograficzna), a także przeprowadzono analizę jednorodności współczynnika wodno-cementowego ocenianą na podstawie rozkładu intensywności barwnika fluoroscencyjnego w świetle UV.

Keywords:

mikrostruktura, cienkie szlify, stuletni beton, wiadukt sklepiony

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Tucholski Z.-other affiliation
26.Jóźwiak-Niedźwiedzka D., Zapobieganie łuszczeniu powierzchni betonowych przy użyciu nawilżonego kruszywa lekkiego. cz. I - stan wiedzy, DROGI I MOSTY, ISSN: 1643-1618, Vol.5, No.2, pp.37-54, 2006
Abstract:

W pracy naszkicowano aktualny stan wiedzy na temat mechanizmów, powodujących powierzchniowe łuszczenie betonów. Uzupełniając opis zjawisk powierzchniowych przytoczono również podstawowe hipotezy, dotyczące wewnętrznej destrukcji betonu, spowodowanej działaniem mrozu, a także przedstawiono pomysł zastosowania „inteligentnego” materiału, tj. nawilżonych drobnych frakcji kruszywa lekkiego jako alternatywy w stosunku do tradycyjnych środków napowietrzających. Ponadto, opisano rodzaje porów występujących w betonie oraz sposób ich wypełnienia przez wodę.

Keywords:

beton nawierzchniowy, odporność na powierzchniowe łuszczenie, wewnętrzna pielęgnacja

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
27.Jóźwiak-Niedźwiedzka D., Zapobieganie łuszczeniu powierzchni betonowych przy użyciu nawilżonego kruszywa lekkiego. Cz. II - badania doświadczalne, DROGI I MOSTY, ISSN: 1643-1618, Vol.5, No.3, pp.17-42, 2006
Abstract:

Praca jest kontynuacją artykułu ‘’Zapobieganie łuszczeniu powierzchni betonowych przy użyciu nawilżonego kruszywa lekkiego. Cz. I – stan wiedzy”. W części II artykułu przedstawiono wyniki badań betonów zawierających nawilżone drobne frakcje kruszywa lekkiego, określono strukturę porów oraz odporność na powierzchniowe łuszczenie (według SS 13 72 44) i mrozoodporność (badaną wg PN-88/B-06250 i przy pomocy pomiaru oporu elektrycznego, według ASTM C 666 A).

Keywords:

beton, mrozoodporność, odporność na powierzchniowe łuszczenie, nawilżone kruszywo lekkie

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
28.Jóźwiak-Niedźwiedzka D., Scaling resistance of high performance concretes containing a small portion of pre-wetted lightweight fine aggregate, CEMENT AND CONCRETE COMPOSITES, ISSN: 0958-9465, Vol.27, No.6, pp.709-715, 2005
Abstract:

The subject of the investigation was the influence of pre-wetted lightweight aggregate on damage of the concrete surface due to cyclic freezing and thawing in the presence of de-icing salts tested according to the Swedish Standard SS 13 72 44 (the Borås method). Six series of concrete specimens were made with the same water/binder (w/b) ratio 0.32, cement volume 400 kg/m3 and content of superplasticiser 8.8 kg/m3. One series, S3/2, contained an air-entraining agent. Series S4/7 and S4/8 were made with water/cement ratio equal to 0.45 and a lower cement content 340 kg/m3. In a few series the sand fraction 0-2 mm and basalt fraction 2-4 mm were partly or totally replaced by wetted lightweight aggregate. Concretes S3/1, S3/3, S4/7 and S4/8, failed the test. The best results were obtained for concrete S3/6 (with the 2-4 mm fraction replaced by half) and S3/2 (air-entrained). The application of an air-entraining agent is more expensive than LWA, and at a construction site it is not always easy to control. It seems that the replacement of a part of aggregate by LWA could be a more effective way to improve the scaling resistance.

Keywords:

concrete, scaling resistance, internal curing, expanded clay

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN

List of chapters in recent monographs
1.
351
Brandt A.M., Jóźwiak-Niedźwiedzka D., Nowowiejski G., Denis P., Dni betonu, Tradycja i Nowoczesność, rozdział: Wyniki badania betonu osłonowego z kruszywem magnetytowym, SPC Stowarzyszenie Producentów Cementu, pp.839-850, 2014
2.
355
Kowalska D., Jóźwiak-Niedźwiedzka D., Chalimoniuk M., Dąbrowski M., Dni betonu, Tradycja i Nowoczesność, rozdział: Zastosowanie metody tomografii komputerowej CT do oceny napowietrzenia betonu, SPC Stowarzyszenie Producentów Cementu, pp.907-918, 2014
3.
284
Jóźwiak-Niedźwiedzka D., Proc. Int. Symp. Brittle Matrix Composites, BMC-10, October 15-17, Warsaw, rozdział: Influence of blended cements on the concrete resistance to carbonation, IFTR and Woodhead Publ., Warsaw, pp.125-134, 2012
4.
285
Ranachowski Z., Jóźwiak-Niedźwiedzka D., Dąbrowski M., Wołowicz J., Sobczak M., Dębowski T., Glinicki M.A., Proc. Int. Symp. Brittle Matrix Composites, BMC-10, October 15-17, Warsaw, rozdział: Microhardness testing procedure applied to blended cement based matrix, IFTR and Woodhead Publ., Warsaw, pp.209-222, 2012
5.
43
Jóźwiak-Niedźwiedzka D., Litorowicz A., Zastosowanie popiołów lotnych z kotłów fluidalnych w betonach konstrukcyjnych, rozdział: Migracja jonów chlorkowych w betonach z popiołami fluidalnymi , Komitet Inżynierii Lądowej i Wodnej PAN, 72, pp.171-186, 2010
6.
44
Jóźwiak-Niedźwiedzka D., Kowalska D., Zastosowanie popiołów lotnych z kotłów fluidalnych w betonach konstrukcyjnych, rozdział: Odporność betonu z popiołami fluidalnmi na agresję mrozu i środków odladzających, Komitet Inżynierii Lądowej i Wodnej PAN, 72, pp.187-208, 2010
7.
46
Brandt A.M., Jóźwiak-Niedźwiedzka D., Małolepszy J., Marks M., Śliwiński J., Kasperkiewicz J., Zastosowanie popiołów lotnych z kotłów fluidalnych w betonach konstrukcyjnych, rozdział: Podsumowanie i wnioski, Komitet Inżynierii Lądowej i Wodnej PAN, 72, pp.339-351, 2010
8.
137
Marks M., Jóźwiak-Niedźwiedzka D., Glinicki M.A., Brittle matrix composites 9, rozdział: Application of machine learning for prediction of concrete resistance to migration of chlorides, Woodhead Publishing Ltd. (United Kingdom), IPPT PAN (Warszawa), Brandt A.M., Li V.C., Marshall I.H. (Eds.), pp.227-236, 2009
9.
143
Jóźwiak-Niedźwiedzka D., Concrete in aggressive aqueous environments - performance, testing and modeling, rozdział: Effect of fluidized bed combustion fly ash on the chloride resistance and scaling resistance of concrete, RILEM (France), Alexander M.G., Bertron A. (Eds.), pp.556-563, 2009
10.
178
Jóźwiak-Niedźwiedzka D., Nontraditional cement & concrete III, rozdział: Scaling resistance and resistivity of concretes containing fluidized bed combustion fly ash, Brno University of Technology, Bilek V., Kersner Z., pp.348-355, 2008
11.
218
Jóźwiak-Niedźwiedzka D., Dni betonu, Tradycja i nowoczesność: konferencja, Wisła, 13-15 października, rozdział: Ocena parametrów struktury napowietrzenia betonów w nawierzchniach lotniskowych, Polski Cement (Kraków), Kijowski P., Deja J. (Eds.), pp.719-727, 2008
12.
237
Jóźwiak-Niedźwiedzka D., Trwałość betonu: metody badań właściwości determinujących trwałość materiału w różnych warunkach eksploatacji: materiały II sympozjum naukowo-technicznego "Cement - właściwości i zastosowanie", [Kraków, 17 kwietnia 2008r.], rozdział: Metody badania mrozoodporności betonu, Wydawnictwo Instytut Śląski (Opole), Sawicka V. (Ed.), pp.161-181, 2008

Conference papers
1.Fantilli A.P., Jóźwiak-Niedźwiedzka D., Gibas K., Dulnik J., The compability between wool fibers and cementitious mortars, ICBBM & EcoGRAFI, Second International RILEM Conference on Bio-based Building Materials 1st Conference on ECOlogical valorisation of GRAnular and FIbrous materials, 2017-06-21/06-23, Clermont-Ferrand (FR), pp.42-47, 2017
Abstract:

The addition of natural fibers residue in cement based materials can be a sustainable technological alternative for traditional dispersed reinforcement, and can improve the performance of brittle matrix materials. The presence of a wool reinforcement can increase the fracture toughness and, at the same time, can reduce the environmental impact of cementitious mortars. The beneficial effects are similarly to those observed in presence of vegetal fibers (e.g., hemp), which have been largely investigated in the literature. However, there are some limits in the use of wool fibers due to their chemical compatibility with the cement matrix, as they can dissolve in alkaline environments. In the present paper, to investigate the compatibility between wool fibers and cementitious mortars, laboratory prototypes have been taken into consideration. Three series of wool-reinforced mortar beams have been cast and cured in water (20°C) or in dry conditions (temp. 20 °C, 50% R.H.) for some days. Portland-limestone cement CEM II has been used, whereas the content of fibers has been limited to about 1% in volume to maintain the workability of the mortars. To investigate the chemical compatibility, and the subsequent effects on the mechanical performances, prototypes have been tested in three point bending. After the mechanical test, the mortars microstructure was evaluated through SEM images and by thin section in transmitted light, in order to individuate a possible relationship between the dissolution of wool and curing conditions. The microstructure observation revealed the capability of wool fibers to bridge the cracks, and to reduce the brittleness of plain mortars. The differences in the mortars microstructure due to alternative curing conditions were also observed and described in the paper. Accordingly, wool could be effectively used to reduce the plastic shrinkage of cementbased composites, like the industrially manufactured polypropylene fibers.

Keywords:

Wool fibers, Plain cement-based mortar, Fiber-reinforced mortar, Polypropylene fibers, Three point bending tests, SEM analyses

Affiliations:
Fantilli A.P.-Politecnico di Torino (IT)
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
Dulnik J.-IPPT PAN
2.Jóźwiak-Niedźwiedzka D., Glinicki M.A., Gibas K., Potential for Alkali–Silica Reaction in Radiation Shielding Concrete Containing Special Aggregates, 5th International Conference on Durability of Concrete Structures, 2016-06-30/07-01, Shenzhen (CN), DOI: 10.5703/1288284316137, No.1134, pp.230-235, 2016
Abstract:

In the present study, the potential for the alkali–silica reaction (ASR) in radiation shielding concrete containing special aggregates is presented. The tests were performed on two kinds of aggregate: (1) high-density aggregate to absorb the gamma radiation (barite, magnetite, and hematite) and (2) mineral with high bound water content to attenuate the neutron flux (serpentinite). The optical microscopy in transparent light on thin sections, XRD and XRF method, was used to assess the mineral composition of aggregates. ASTM C1260 test method for potential alkali reactivity of aggregates was applied also to investigate the effect of different content and crystal size of silica on the expansion due to ASR. The tests revealed that all tested aggregates, such as barite, magnetite, hematite, and serpentinite, were characterized by low solubility at high pH. The XRD and XRF results have shown presence of silica in all tested aggregates, but the microscopic observations enhanced size and composition of SiO2 crystals. The aggregates were not deleterious themselves, but the different content and size of SiO2 crystals in the aggregate influenced their potential for alkali–silica reaction. The quartz in heavy kinds of rocks and in the serpentinite used for radiation shielding was just as much potentially susceptible to deleterious ASR as quartz in common rocks used in concrete technology. In the hematite, silica crystals were classified as microcrystalline, so it should be considered as potentially reactive. The expansion tests confirmed that hematite was highly reactive. Other aggregates after 14 days of testing did not exceed 0.1% elongation limit. The microstructural analysis of thin sections prepared from mortars after ASTM C1260 test confirmed expansion of aggregate grains due to ASR.

Keywords:

Alkali-Silica Reaction (ASR), ionizing radiation, high density aggregate

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Glinicki M.A.-IPPT PAN
Gibas K.-IPPT PAN
3.Glinicki M.A., Dąbrowski M., Skrzypczyński M., Jóźwiak-Niedźwiedzka D., Gibas K., Curing performance indicators of exposed aggregate layer in two-lift concrete pavement, ICCP, 11th International Conference on Concrete Pavements, 2016-08-28/09-01, San Antonio (US), pp.753-762, 2016
Abstract:

The use of exposed aggregate concrete (EAC) in the upper layer of two-lift pavements is spread over many European countries including Poland. However, the EAC technology is considered difficult to apply because of inevitable dependence on operator's experience to control the whole process properly. The proper timing of technological operations is critical. The investigation on the performance of EAC was performed to gain a better understanding of material and environmental factors involved. EAC slabs were manufactured in the laboratory following the procedure applied at the construction site. Air entrained concrete mix design included a variable water to cement ratio and cement type while the type and the content of aggregate was constant. The effects of curing intensity were studied. The strength properties, air void characteristics of hardened concrete, the freeze-thaw resistance and the salt-scaling resistance were tested of specimens cored from the slabs, using the European standard methods. EAC permeability was also evaluated using the methods covered by ASTM C1585 and NT Build 492. Such permeability indicators and frost durability were applied to evaluate the differences in EAC layers performance. The environmental vulnerability of EAC mixes used in the upper layer of two-lift pavements is discussed.

Keywords:

air entrainment, blended cement, concrete durability, curing technology, highway pavement, mix design, permeability

Affiliations:
Glinicki M.A.-IPPT PAN
Dąbrowski M.-IPPT PAN
Skrzypczyński M.-other affiliation
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
4.Ranachowski Z., Jóźwiak-Niedźwiedzka D., Ranachowski P., Dąbrowski M., Kúdela Jr S., Dvorak T., Analysis of pore distribution and connectivity in concrete using X-ray microtomography, BMC-11, 11th International Symposium on Brittle Matrix Composites, 2015-09-28/09-30, Warsaw (PL), pp.203-212, 2015
Abstract:

In the paper a method of X-ray microtomography (micro-CT) was employed for a direct insight into a microstructure of concrete with a practical resolution of approx. 10 micrometers3. Two sets of specimens were subjects of examination. The spatial concentration of air pores was investigated in three concretes differing in the amount of the supplement of high calcium fly ash (HCFA). The parameter of pore connectivity called diffusive tortuosity was determined in three other concretes made of the same ingredients but differing in water to cement ratio. The quantitative results obtained with application of described procedures are applicable in material characterization.

Keywords:

X-ray microtomography, concrete, microstructure

Affiliations:
Ranachowski Z.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Ranachowski P.-IPPT PAN
Dąbrowski M.-IPPT PAN
Kúdela Jr S.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
Dvorak T.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
5.Jóźwiak-Niedźwiedzka D., Glinicki M.A., Gibas K., Jaskulski R., Denis P., Garbacik A., Alkali-silica expansion of heavy aggregates used for nuclear shielding concrete, BMC-11, 11th International Symposium on Brittle Matrix Composites, 2015-09-28/09-30, Warsaw (PL), pp.353-360, 2015
Abstract:

In the present study the potential appearance of the alkali-silica reaction (ASR) in heavy aggregates was studied. ASTM C1260 Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method) was applied. In order to investigate the effect of the content of alkalies in cement on the expansions due to ASR, three levels of total and soluble alkali content of cement were studied. Three portland cements Type I with different alkali content were selected. Two ordinary portland cements, which are commonly available in the market and one special cement were tested. That cement was specially made for the purpose of the nuclear shielding concrete CEM I NA-SR-LH of low-alkali, increased sulphate resistance and low heat of hydration. For the tests according to ASTM C 1260 the high-density aggregates, known as absorbing gamma radiation were selected: barite, magnetite and hematite. The expansion test revealed that hematite was highly reactive, regardless of the type of cement. Already after four days of storage in 1 N NaOH and 80°C the mortar bar expansion exceeded the limit of 0.1%, and after next four days was more than 0.2%., which qualifies it extremely reactive aggregate. Other aggregates after 14 days of testing did not exceed 0.1% elongation limit, but the influence of the type of cement was noticed. There was a noticeable tendency for increasing the total expansion with increasing the alkali content of cement.

Keywords:

Alkali-Silica Reaction (ASR), high density aggregate, cement composition

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Glinicki M.A.-IPPT PAN
Gibas K.-IPPT PAN
Jaskulski R.-IPPT PAN
Denis P.-IPPT PAN
Garbacik A.-Institute of Ceramics and Building Materials (PL)
6.Jóźwiak-Niedźwiedzka D., Gibas K., Brandt A.M., Glinicki M.A., Dąbrowski M., Denis P., Mineral composition of heavy aggregates for nuclear shielding concrete in relation to alkali-silica reaction, Procedia Engineering, ISSN: 1877-7058, DOI: 10.1016/j.proeng.2015.06.132, Vol.108, pp.162-169, 2015
Abstract:

The results of microscopic analysis on thin sections of aggregates intended for nuclear shielding concrete are presented. The petrographic analysis was performed on different barite, magnetite and hematite aggregates used as the high-density aggregate to absorb gamma radiation. Both optical microscopy and accelerated expansion tests were used to recognise the potential for alkali-reactivity of the aggregates. The mineral composition of the tested aggregates was analysed on thin sections in transmitted cross-polarized light and XRD tests were additionally performed. Expansion tests of mortar bars exposed to 1 N NaOH solution at the temperature of 80°C were also performed following ASTM C1260. The high-density aggregates contained ore deposits - metallic opaque phases providing the required shielding properties. These aggregates also contained various amounts of non-metallic phases, with both innocuous non-ore minerals and deleterious, potentially reactive materials. Barite aggregates contained siderite, fluorite and hawleyite in varying amounts, apart from the barium sulphate being the principal component. Moreover, particularly reactive cristobalite and muscovite were identified in barite aggregates from certain quarries. Tests according to ASTM C1260 performed on mortars showed the expansion above the accepted criterion for non-reactive aggregate and confirmed the threat due to the presence of cristobalite in barite aggregates.

Keywords:

high-density aggregate, heavy concrete, alkali-silica reaction, thin section, XRD

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
Brandt A.M.-IPPT PAN
Glinicki M.A.-IPPT PAN
Dąbrowski M.-IPPT PAN
Denis P.-IPPT PAN
7.Gibas K., Glinicki M.A., Jóźwiak-Niedźwiedzka D., Dąbrowski M., Nowowiejski G., Gryziński M., Properties of the thirty years old concrete in unfinished Żarnowiec Nuclear Power Plant, Procedia Engineering, ISSN: 1877-7058, DOI: 10.1016/j.proeng.2015.06.127, Vol.108, pp.124-130, 2015
Abstract:

The construction of Żarnowiec Nuclear Power Plant (NPP) facilities was discontinued in 1989, despite the high level of work advancement. Already a large part of the concrete structures was built, now submerged in water from Żarnowieckie Lake. These structures were exposed over 30 years to the environmental conditions (rain, and varying high and low temperatures) without any special maintenance treatment. The technological documentation archives are not available. Experimental testing of specimens drilled out from different concrete structure elements was performed in September 2014.
The goal of the research was the identification of the composition of concrete and its present properties, especially the recognition of the effects of long-term environmental impact. The scope of the research covered macroscopic and microscopic analysis of concrete, compressive strength test, permeability test defined as the rate of chloride ions migration and water absorption. Unfortunately, the most important parts of the concrete structure are not available for testing because they are under water level. The obtained results allowed to classify the concrete structural elements in nuclear power plants buildings as of a quite good quality.

Keywords:

durability, old concrete, strength, microstructure, permeability

Affiliations:
Gibas K.-IPPT PAN
Glinicki M.A.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Dąbrowski M.-IPPT PAN
Nowowiejski G.-IPPT PAN
Gryziński M.-other affiliation
8.Brandt A.M., Jóźwiak-Niedźwiedzka D., On the application of dispersed fibres as reinforcement for concrete shields against radiation, HPFRCC7, 7th RILEM Workshop on High Performance Fiber Reinforced Cement Composites, 2015-06-01/06-03, Stuttgart (DE), pp.153-160, 2015
Abstract:

The application of fibre reinforced concrete (FRC) in the various constructions in Nuclear Power Plants and particularly in the shields for protection against y and neutron radiation seems possible and useful. A few examples of shields built with FRC are described and rewieved and the question is formulated why this kind of cement based composites are rather infrequently used in that area.

Keywords:

fibre reinforced concrete (FRC), nuclear power plant (NPP), special concrete

Affiliations:
Brandt A.M.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
9.Jóźwiak-Niedźwiedzka D., Gibas K., Brandt A.M., Denis P., Influence of barite composition on potential alkali aggregate reaction in radiation-shielding concrete, TINCE 2014, 2nd International Conference on Technological Innovations in Nuclear Civil Engineering, 2014-09-01/09-04, Paryż (FR), pp.1-12, 2014
Abstract:

In the paper the barite aggregate has been analyzed as a potential source of ASR in heavy concrete. Special attention was paid to BaSO4 and minor mineral components in aggregates and their influence on ASR development in tested mortars

Keywords:

heavy aggregate, Alkali Silica Reaction (ASR), ionizing radiation

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN
Brandt A.M.-IPPT PAN
Denis P.-IPPT PAN
10.Jain J., Olek J., Janusz A., Jóźwiak-Niedźwiedzka D., Effects of Salt Solutions on Physical Parameters of Pavement Concretes, 91st Annual Meeting, Transportation Research Board, 2012-01-22/01-26, Washington (US), No.2735-12, pp.1-13, 2012
Abstract:

Salt solutions are employed on pavement surfaces throughout wintry weather environment to guarantee safe driving conditions. Recently, deicing solutions of CaCl2 or MgCl2 (or sometimes rock salt (NaCl) pretreated with CaCl2 or MgCl2 brines,) are used to provide a more consistent ice and snow control. This paper assesses the effects of more prevalently used salt solutions on the microstructure and physical parameters (strength, expansion and mass) of pavement concretes. Deicing solutions of NaCl, CaCl2, and MgCl2 were used for wetting-drying (WD) and freezing-thawing (FT) conditions with total ion molality of 10.5 and 5.5 respectively.
The prismatic and cylindrical specimens were used to monitor physical changes due to these regimes and later on microstructural analysis was performed on them after the completion of exposure. The changes on cylindrical specimens due to WD regime were monitored by taking UPV measurements and crushing these cylinders at the end for compressive strength. The effects on prismatic specimens were monitored by measuring mass and resonant frequencies after every 2 weeks and used for calculating relative dynamic modulus of elasticity.
To study unidirectional penetration of deicers, several 3 in. (76 mm) diameter concrete cylinders were ponded with the deicing solutions in WD environment. These cylindrical specimens were used for SEM analysis and chloride profile grinding after end of the exposure. The microstructure of prismatic concretes specimens exposed to 350 FT cycles was observed using personnel SEM from two locations (one from the center and other from the edge) of the after conclusion of the both exposure conditions.

Keywords:

Physical Parameters, Pavement Concretes, Salt Solutions

Affiliations:
Jain J.-Purdue University (US)
Olek J.-Purdue University (US)
Janusz A.-Purdue University (US)
Jóźwiak-Niedźwiedzka D.-IPPT PAN
11.Jóźwiak-Niedźwiedzka D., Glinicki M.A., Dąbrowski M., Application of microscopic techniques for studying microstructure of air-entrained concretes containing high calcium fly ash, 33rd International Conference on Cement Microscopy, 2011-04-17/04-20, San Francisco (US), pp.372-383, 2011
Abstract:

The possibility of using the high calcium fly ash (HCFA) as type II concrete additive is not well established, especially in relation to the durability of concrete structures in aggressive environment. The paper presents results of microstructural characterization of air-entrained concrete containing high calcium fly ash from lignite combustion. Frost resistant concretes were designed with different content of fly ash use for cement replacement by 15% and 30%. Different kinds of HCFA were used: raw (unprocessed) and grinded during 10, 15 and 28 minutes. The evaluation of the microstructure was performed using SEM and optical microscopy on thin sections and plane sections. All thin sections were impregnated with epoxy containing fluorescent dye and were examined using ordinary light, crossed polarized light and UV light. The thin section evaluation involved petrographic characterization of aggregates and examination of paste quality. Automatic air-void analysis on plane sections revealed air-content, specific surface, spacing factor and the content of micropores in the hardened concrete. Significant differences in particle shape and size before and after grinding of the HCFA were revealed by SEM analysis. The results of thin section analysis of the high calcium fly ash concrete showed that its microstructure was more dense than that of the ordinary concrete. The influence of specific surface of fly ash on air void content in HCFA concrete was found.

Keywords:

high calcium fly ash (HCFA), air-entrained concretes, microstructural characterization

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Glinicki M.A.-IPPT PAN
Dąbrowski M.-IPPT PAN
12.Jain J., Janusz A., Olek J., Jóźwiak-Niedźwiedzka D., Physico-chemical Changes in Plain and Fly Ash Modified Concretes Exposed to Different Deicing Chemicals, XIII ICCC, 13th International Congress on the Chemistry of Cement, 2011-07-03/07-08, Madrid (ES), pp.1-7, 2011
Abstract:

The deicing/anti-icing chemicals are routinely used during cold weather to ensure safe driving conditions. Traditionally, solid rock salt (NaCl) or NaCl brines have been used for these purposes but their efficiency is reduced at lower temperatures. In order to provide a more reliable means of ice and snow control, chemicals with lower freezing points, such as CaCl2 or MgCl2 (or sometimes rock salts pretreated with CaCl2 or MgCl2 brines) are increasingly being applied. The extent and magnitude of chemical reactions of these “new-generation” deicers with pavement concrete is still somewhat unclear. This paper presents the results of investigation of the physicochemical changes in the microstructure of pavement concrete exposed to different deicers and subjected to both wetting/drying (W/D) and freezing/thawing (F/T) regimes.
Plain concretes (PC) and fly ash modified concretes (20% mass replacement of cement) with water-to-cementitious materials ratio of 0.42 were exposed to three different types of deicing solutions, with total ion molality of, respectively, 10.5 for W/D and 5.5 for F/T regimes. For comparison purposes, additional set of specimens was kept in deionized water under similar exposure regimes. The companion controlled specimens were kept in saturated limewater at 23oC. The physical changes taking place in the prismatic (3” x 3” x 11.5”) specimens were monitored weekly and included measurements of dynamic modulus of elasticity (RDME) and mass changes. After 154 W/D cycles prismatic specimens exposed to 28% CaCl2 solution exhibited considerable visual distress, reduction in mass, and reduction in DME . The same deicer also caused reduction in mass and in DME after only 35 F/T cycles. The performance of fly ash modified concretes was better than that of PC in all deicing solutions under both W/D and F/T regimes.
To ensure a unidirectional penetration of deicers, several 3–in. diameter concrete cylinders were ponded with the same deicing solutions as the prismatic beams while being exposed to W/D cycles. These cylinders were used to prepare the SEM analysis samples.

Keywords:

plain concrete, fly ash concrete, deicing salts, pavement concrete

Affiliations:
Jain J.-Purdue University (US)
Janusz A.-Purdue University (US)
Olek J.-Purdue University (US)
Jóźwiak-Niedźwiedzka D.-IPPT PAN
13.Jóźwiak-Niedźwiedzka D., Kowalska D., Cienkie szlify w ocenie trwałości mrozowej betonów z popiołem fluidalnym, Konferencja Dni Betonu "Tradycja i nowoczesność", 2010-10-11/10-13, Wisła (PL), pp.757-766, 2010
Abstract:

W referacie przedstawiono wyniki oceny mikrostruktury betonów z dodatkiem popiołów fluidalnych (pf) po badaniu mrozoodporności i odporności na powierzchniowe łuszczenie. Metodą cienkich szlifów przeprowadzono analizę mikrostruktury betonu przed i po badaniu trwałości mrozowej. Wszystkie cienkie szlify były zaimpregnowane żywicą z fluorescencyjnym barwnikiem i analizowane w świetle przechodzącym spolaryzowanym, przy równoległych i skrzyżowanych nikolach oraz w świetle UV. Na cienkich szlifach betonowych przeprowadzono analizę petrograficzną kruszywa i ocenę jakości zaczynu cementowego (łącznie ze sprawdzeniem rzeczywistego współczynnika wodno-spoiwowego). Analiza cienkich szlifów betonów z pf przed badaniem trwałości mrozowej, wykazała, że ich mikrostruktura jest bardziej zwarta niż betonu bez popiołu. Jednak, po cyklicznym zamrażaniu i odmrażaniu, betony z dodatkiem popiołu wykazały na cienkich szlifach liczne spękania w odróżnieniu do betonu bez popiołu fluidalnego. W betonie bez pf w strefie kontaktowej kruszywo-zaczyn zaobserwowano strefy umiejscowione pod kruszywem grubym z mniej zwartą strukturą zaczynu. Wyniki analizy cienkich szlifów wykazują, że zastosowana metoda badania mrozoodporności, oparta na pomiarze zmiany wytrzymałości na ściskanie, powinna być skorygowana aby lepiej odwzorowywała zniszczenie zachodzące w mikrostrukturze betonu.

Keywords:

popiół fluidalny, beton, trwałość, mrozoodporność, mikrostruktura, cienkie szlify

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Kowalska D.-IPPT PAN
14.Glinicki M.A., Jóźwiak-Niedźwiedzka D., Gibas K., Ocena przepuszczalności betonu z popiołem lotnym wapniowym - koncepcja badań, V Konferencja "Energia i Środowisko w technologiach materiałów budowlanych, ceramicznych, szklarskich i ogniotrwałych", 2010-06-09/06-11, Ustroń (PL), pp.229-240, 2010
Abstract:

Celem rozpoczętych badań jest ocena przepuszczalności betonu zawierającego popiół lotny wapienny pochodzący ze spalania węgla brunatnego w energetyce zawodowej, w szczególności jakościowe rozpoznanie i określenie ilościowe wpływu składnika popiołowego w cemencie lub dodatku popiołu do betonu na wnikanie mediów agresywnych. W referacie przedstawiono podstawowe koncepcje badawcze oraz wyniki określania szczelności betonu na podstawie literatury. Stwierdzono, że można oczekiwać korzystnych efektów stosowania popiołu lotnego wapiennego, ujawniających się znaczącą redukcją współczynnika dyfuzji i współczynnika migracji chlorków, a także efektów niekorzystnych polegających na zwiększeniu przepuszczalności powietrza i ewentualnie podwyższeniu szybkości karbonatyzacji.

Keywords:

popiół lotny wapienny, trwałość, beton

Affiliations:
Glinicki M.A.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Gibas K.-IPPT PAN

Conference abstracts
1.Ranachowski Z., Jóźwiak-Niedźwiedzka D., Ranachowski P., Pawełek A., Kúdela Jr S., Dvorak T., The analysis of pore distribution and pore connectivity in concrete samples using x-ray microtomography, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.199-200, 2014
Abstract:

The durability of concrete in outdoor structures is closely related to its resistance against the aggressive gaseous actions coming from the environment and including influence of oxygen, nitrogen, carbon dioxide. The pore system and its interconnectivity in the concrete matrix directly influence the possibility of penetration of various aggressive gaseous media into concrete structure. The X-ray microtomography (micro-CT) is a modern, non-invasive technique enabling for determination of existing pores in the microstructure of concrete matrix. In the paper the results of investigation of two different concretes by the application of micro-CT method to micro-cores are presented. The quantitative information on the parameters of the analysed microstructure can improve the methods of material characterization available up to now.

Keywords:

X-ray microtomography, concrete, microstructure

Affiliations:
Ranachowski Z.-IPPT PAN
Jóźwiak-Niedźwiedzka D.-IPPT PAN
Ranachowski P.-IPPT PAN
Pawełek A.-other affiliation
Kúdela Jr S.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
Dvorak T.-Institute of Materials and Machine Mechanics, Slovak Academy of Sciences (SK)
2.Jóźwiak-Niedźwiedzka D., Microstructure and strength of mortars made with blended cements containing high calcium fly ash, 58th Conference on Scientific Problems of Civil Engineering, 2012-09-16/09-21, Krynica (PL), pp.206-207, 2012
Abstract:

The focus of this paper is on the microstructure, microhardeness and early strength of mortars made with different blended cement containing high calcium fly ash. The research was concerning prototype cements CEM I and CEM V made in the laboratory conditions. Optical microscopy with image analysis, scanning electron microscopy with EDX analysis and depth-sensing indentation were applied. The compressive and tensile strength was determined according to appropriate standards. The compressive strength of mortars made with blended containing high calcium fly ash after 28 days of hardening was lower than compressive strength of reference mortar with cement CEM I. The strength was lower in comparison with the reference mortar by 11 and 41% and it was clearly dependent on the content of high calcium fly ash, siliceous fly ash or ground granulated blastfurnance slag in the cement. The compressive strength was decreasing with increase of content of additions in cement. All the pastes were characterized by a similar C-S-H structure, so-called “honey comb”, the presence of the portlandite plates, relicts of the nonhydrated cement grains and spherical grains from fly ash.

Keywords:

microstructure, microhardeness, early strength, high calcium fly ash

Affiliations:
Jóźwiak-Niedźwiedzka D.-IPPT PAN

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421123
2017-03-31
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Glinicki M., Dąbrowski M., Jóźwiak-Niedźwiedzka D., Gibas K., Sobczak M., Brandt A.M.
Mieszanina do impregnacji kruszywa mineralnego, kruszywo mineralne łamane i beton osłonowy konstrukcyjny, zwłaszcza na osłony radiologiczne
PL, Instytut Podstawowych Problemów Techniki PAN
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390206
2010-01-18
BUP 20/10
2010-09-27
Małolepszy J., Deja J., Łagosz A., Mróz R., Śliwiński J., Tracz T., Kańka S., Zybura A., Domagała K., Czarnecki L., Woyciechowski P., Radomski W., Mossakowski P., Brandt A.M., Glinicki M.A., Marks M., Jóźwiak-Niedźwiedzka D., Sobczak M.
Środek zwiększający trwałość i szczelność betonu konstrukcyjnego
PL, Akademia Górniczo-Hutnicza im. Stanisława Staszica, Instytut Podstawowych Problemów Techniki PAN
215604
WUP 01/14
2014-01-31