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1
Content available Particle size characterisation of SCMs by mercury intrusion porosimetry
Klemm A. J., Wiggins D. E.
Fizyka Budowli w Teorii i Praktyce
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2017
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T. 9, nr 1
5--12
EN
Mercury intrusion porosimetry (MIP) is widely used for the microstructural characterisation of porous solids. Comparatively few studies have employed the technique to characterise the size of particles within powdered samples. The present study uses the MIP technique to characterise the particle sizes of contemporary supplementary cementitious materials (SCMs), and in particular uses the technique to present particle size distributions, rather than a single mean size. Representivity of the technique for known limitations of non-spherical and porous particles are checked using the Scanning Electron Microscope. The findings indicate that the MIP affords a good approximation of particle sizes, including distributions, of spherical and non-spherical particles. The technique was also found to provide reasonable accuracy for estimating the particle sizes of highly porous particles, where distinction between inter-particle and intra-particle porosity was made.
2
Content available Current trends in development of lime based composites
Olaniyan S. A., Klemm A. J.
Fizyka Budowli w Teorii i Praktyce
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2015
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T. 7, nr 3
49--54
EN
Prior to the beginning of this century, lime dominance as a building material particularly, lime mortar was incontrovertible. Reminiscence of this is reflected in many buildings of historic references which stand till date as their durability features are predominantly attributed to lime’s inherent properties of flexibility, plasticity and breathability, among others. However, lime’s characteristic long ‘setting and hardening’ periods, low mechanical strength and poor internal cohesion coupled with subsequent discovery of Portland cement put its use into decline. In this paper, new approaches involving lime based composites aimed at maximising lime’s sterling features while improving its identified shortcomings are highlighted. The focus is particularly on lime based mortars blended with cement and ‘Ground Granulated Blast Furnace Slag’ (slag) in varying compositions individually, for improved performances. As this effort attempts to evolve lime revival for new constructions, it will also serve as a befitting response to the phenomena climate change with a view to minimising construction impacts on the environment.
3
Content available Niektóre wskaźniki procesów wzajemnego oddziaływania promieniowania laserowego z materiałami
Klemm A. J, Rożniakowski K
Fizyka Budowli w Teorii i Praktyce
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2011
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T. 6, nr 3
27--30
PL
W pracy przedstawiono wyniki badań oddziaływania wiązki światła lasera z wybranymi materiałami stosowanymi w budownictwie. Zaobserwowane zjawiska mogą być czynnikiem charakteryzującym proces wzajemnego oddziaływania światła z wybranymi materiałami. Ponadto, te zjawiska mogą być przydatne do wyznaczania własności fizycznych tych materiałów. Mogą zatem stanowić wskaźniki charakteryzujące te zjawiska.
EN
The work presents some examinations of the laser beam interaction phenomena with building materials. The observed phenomena and assumed their physics parameters can be the indicators proposed in this paper.
4
Content available Application of He-Ne laser in surface metrology of porous construction materials
Klemm A. J, Rożniakowski K
Fizyka Budowli w Teorii i Praktyce
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2011
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T. 6, nr 2
41--52
EN
Application of laser radiation (He-Ne laser) in surface metrology of porous construction materials is relatively new concept. Non-contact measurement of surface alterations is based on analysis of the reflected light parameters. Although such analysis can be very complex due to highly developed roughness of surfaces they proved to be very informative. In this paper, two methods - laser speckle method and reflected light intensity method are presented and compared. The average surface modification factor, obtained from the laser speckle method and from reflected light intensity method shows a very good correlation.
5
Content available Effects of laser radiation on the cementitious materials - three case studies
Klemm A. J., Rożniakowski K.
Fizyka Budowli w Teorii i Praktyce
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2009
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T. 4
79-84
EN
Laser processing is unarguably associated with some alterations of cementitious materials' geometrical microstructure and chemical composition. Since high temperature is involved in the laser cleaning process, the chemical composition of surfaces may change, followed by crack development and subsequent changes of roughness. The relationship between laser treatment and substrate parameters is a two-way relationship. The great variation in absorptivity of highly developed surfaces of cementitious materials results in substantial differences in their responses to laser irradiation. Paper presents selected results of three investigations on the effect of laser radiation on characteristics of porous cementitious materials.
6
Content available remote The effect of superplasticisers on OPC and PPFA concrete
Moffat I., Klemm A. J.
Budownictwo o Zoptymalizowanym Potencjale Energetycznym
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2007
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nr (4)
219--225
EN
Although the use of superplasticisers within cement is well established, there is still lack of consensus on their effect on the hydration process. The problem complicates even further, when superplastizisers are incorporated into the concrete mix containing Pfa as partial replacement. The aim of the paper therefore was twofold: firstly to assess the effect of partial replacement of OPC by PFa and secondly, to explore the effect of increased lever of superplasticizing admixture and reduced cement content on the PPFA. Comparative studies have demonstrated that improved long-term performance to that of OPC concrete is achievable with the addition of pulverized fuel ash (PPFA). Early strength of the PPFAC concrete is however compromised with parity being obtained after 80 days. Increased level of cement and PFA content does not always provide satisfactory results in terms of the 28 days compressive strength. Increased amount of fines and water content may lead to heaping up of the cement particles and altering workability. Introduction of a superplasticiser reduces water demand without the need to change the cement content. It is possible therefore to produce a concrete of 40 N/mm² strength and reduced level of water absorption.
7
Content available remote Performance of cement-based materials exposed to cyclic freezing and thawing - microstructural alterations
Wieloch M., Klemm A. J.
Budownictwo o Zoptymalizowanym Potencjale Energetycznym
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2007
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nr (4)
412--421
EN
This article presents the results of a part of investigation on the performance of cement-based mortars subjected to omnidirectional freezing and thawing tests. Microstructural changes due to exposure of up to 732 freezing and thawing cycles are documented on Ordinary Portland Cement mortar of varied maturity. The results yielded by the Mercury Intrusion Porosimetry are used to assess the alterations due to freezing and thawing when compared against corresponding samples cured in laboratory conditions. The representation of pore structure obtained in the investigation of mortars is intended to study the changes in pore structure due to frost deterioration.
8
Content available The Effects of pore structure on freezing and thawing deterioration
Klemm A.J., Wieloch M., Klemm P.
Fizyka Budowli w Teorii i Praktyce
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2005
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T. 1
190-200
EN
Manufacturing of concrete resistant to freezing and thawing requires an in de understanding of the mechanisms triggering deterioration. Despite numerous attempts, a definitive and fully explanatory model has yet to be formulated. This paper presents part of study which analyzes influence of pore structure of cement-based matrix on the frost durability of Ordinary Portland Cement mortar is analysed. An empirical investigation was carried out on five air-entrained and one non-air- entrained mortar (with water-to-binder (W/B) ratio 0.4) subjected up to 732 freezing/thawing (Frr) cycles. Various concentrations of air-entraining admixture were used to differentiate the pore-structure of mortar. The examination of the microstructure and composition of the cement paste was performed by means of Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP). Presented results demonstrate the magnitude of alterations to pore configuration due to pure freezing/thawing and its effect on the mechanical characteristics (compressive/flexural strength). Finally, on the grounds of apparent transformation. a generic pore size distribution of frost resistant cement-matrix is proposed.
9
Laserowa restauracja warstwy wierzchniej
Klemm P., Rożniakowski K., Klemm A. J.
Zeszyty Naukowe Politechniki Świętokrzyskiej. Budownictwo
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2001
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Z. 39
41-46
PL
W pracy przedstawiono charakterystyczne wyniki badań dotyczące laseroego usuwania zanieczyszczeń i modyfikacji warstwy wierzchniej za pomocą impulsowego promieniowania laserowego. Obiektem badań był szereg próbek cegły pochodzącej z Kościoła o.o. Jezuitów w Łodzi. W badaniach stosowano metody mikroskopii elektronowej (SEM) i mikroanalizy rentgenowskiej.
EN
Restoration of ancient artwork and architecture requires even more effective cleaning techniques than are currently available. Laser cleaning appears to be a suitable method for removing surface contaminants from porous materials. This paper presents some effects of laser beam interaction with cleam and contaminated surface of brick.The effects of the laser beam interaction with clean and contaminated surface of brick. The effects of the laser beam interaction have been examined by the scanning electron microscopy and X-ray microanalysis.
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