Elżbieta Janowska-Renkas - Academia.edu (original) (raw)
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Papers by Elżbieta Janowska-Renkas
Energies, Feb 4, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Roczniki Inżynierii Budowlanej, 2006
Inżynieria i Budownictwo, 2016
Roczniki Inżynierii Budowlanej, 2009
Construction and Building Materials, 2013
Abstract The impact of chemical structure of four new-generation superplasticizers–derivatives of... more Abstract The impact of chemical structure of four new-generation superplasticizers–derivatives of either acrylic acid (denoted as SP-A and SP-B) or maleic acid (SP-C and SP-D) – on their efficiency in cementitious pastes was studied. Gel permeation chromatography (GPC) and Fourier-Transformed Infrared Spectroscopy (FTIR) were applied to investigate the superplasticizers’ molecular structure. The performance of a superplasticizer, i.e. reduction in plastic viscosity, was proven to be dependent on its chemical structure. The maleic-based superplasticizers, having longer backbones and side chains as well as carboxylic groups (COO−), thus displaying higher molecular mass and hydrophilicity, are more efficient. On the other hand, the acrylic acid derivatives, with shorter backbones and side chains and without carboxylic groups, appear less efficient. It was also proven that the maleic-based superplasticizers slow the hydration process down to a much greater extent than acrylic acid-derived superplasticizers.
Inżynieria i Budownictwo, 2007
MATEC web of conferences, 2018
The study presents the state of knowledge regarding physical and chemical properties, as well as ... more The study presents the state of knowledge regarding physical and chemical properties, as well as trends for application of fly ashes from combustion in fluidized bed boilers in building materials. Clinker-slagash based binders were tested that contained up to 40 mass % of fly ashes from combustion in fluidized bed boilers. It was demonstrated that fluidized bed combustion fly ashes (FBC fly ash), apart from granular blast furnace slag, could be the ingredient of low clinker Portland cements (ca. 20% by mass). These cements, compared to CEM I Portland cement, have higher water demand and durability in the corrosive environment, and a lower compressive strength value. Based on test results of binders with various content of blast furnace slag and fly ash, the clinker-slag-ash based binder was singled out, which demonstrated the higher durability in the corrosive environment. It was found that production of clinker-slag-ash based binders was possible in the strength class 32.5 even with 30% by mass of FBC fly ash content.
Topics in Catalysis, Mar 8, 2013
Short-channel structures of triangular and sinusoidal channel cross-sectional shape were examined... more Short-channel structures of triangular and sinusoidal channel cross-sectional shape were examined experimentally to find their heat (or mass) transfer and flow friction (flow resistance) characteristics. A particular emphasis was placed on influence of the channels length (referred to its hydraulic diameter) on transport and hydrodynamic characteristics. The transport and friction properties were correlated in terms of dimensionless channel length with satisfactory accuracy. The dimensionless channel length was proved to be a key factor that determines the transport and friction coefficients. Comparison with ceramic monolith has shown possibility of using the structures in automotive catalytic converters.
Construction and Building Materials, 2012
This paper presents research results of superplasticizers effect on rheological properties of cem... more This paper presents research results of superplasticizers effect on rheological properties of cement pastes containing blast furnace slag. The percentage of slag was from 20% to 80% by mass of cement. The specific surface of slag was similar to cement according to Blaine'a but the slag contained smaller percentage of fine fraction than cement. It was found that superplasticizer addition lowers rheological parameters of cement pastes. The decrease of rheological parameters depends on fine fraction contents in cement. Various degree of fluidity of cement pastes (C3 and CEM III/A 32.5) with similar contents of slag (about 60%) results from different amount of fine fraction below 20 lm.
Zeszyty Naukowe Politechniki Gdańskiej. Budownictwo Lądowe, 2006
Budownictwo i Architektura, Sep 11, 2013
W pracy przedstawiono wyniki bada budowy strukturalnej superplastyfikatorów nowej generacji stoso... more W pracy przedstawiono wyniki bada budowy strukturalnej superplastyfikatorów nowej generacji stosowanych w technologii betonu. Badania struktury superplastyfikatorów przeprowadzono na próbkach przy wykorzystaniu chromatografii elowej (GPC) oraz fourierowskiej spektroskopii absorpcyjnej w podczerwieni (FTIR). Przedstawiono wyniki bada wp ywu tych superplastyfikatorów na w a ciwo ci reologiczne zaczynów cementowych. Wykazano, e skuteczno dzia ania superplastyfikatora (zmniejszenie lepko ci plastycznej) wzrasta z: zawarto ci polimeru superplastyfikatora w ca kowitej masie posyntezowej próbki produktu technicznego, mas molow wagowo-redni (M w) polimeru superplastyfikatora, obecno ci wolnych grup karboksylowych lub bezwodnikowych w polimerze oraz hydrofilowo ci polimeru superplastyfikatora: okre lon stosunkiem absorbancji hydrofilowych grup eterowych do hydrofobowych grup estrowych w a cuchu polimerowym. Powy sze stwierdzono dla superplastyfikatorów pochodnych kawasów: akrylowego (SP-A1 i SP-A2) i maleinowego (SP-M2 i SP-M1). Skuteczno dzia ania superplastyfikatorów maleje wraz ze wzrostem zawarto ci wolnych, nieprzereagowanych z kwasami lub bezwodnikiem poli(glikoli etylenowych) PEG. Wykazano, e superplastyfikatory pochodne bezwodnika maleinowego (SP-M1 i SP-M2) o wi kszej hydrofilowo ci (wykazanej badaniami strukturalnymi) charakteryzuj si wi ksz skuteczno ci dzia ania ni superplastyfikatory pochodne kwasu akrylowego (SP-A1 i SP-A2).
Construction and Building Materials, Jun 1, 2013
Energies, Feb 4, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Roczniki Inżynierii Budowlanej, 2006
Inżynieria i Budownictwo, 2016
Roczniki Inżynierii Budowlanej, 2009
Construction and Building Materials, 2013
Abstract The impact of chemical structure of four new-generation superplasticizers–derivatives of... more Abstract The impact of chemical structure of four new-generation superplasticizers–derivatives of either acrylic acid (denoted as SP-A and SP-B) or maleic acid (SP-C and SP-D) – on their efficiency in cementitious pastes was studied. Gel permeation chromatography (GPC) and Fourier-Transformed Infrared Spectroscopy (FTIR) were applied to investigate the superplasticizers’ molecular structure. The performance of a superplasticizer, i.e. reduction in plastic viscosity, was proven to be dependent on its chemical structure. The maleic-based superplasticizers, having longer backbones and side chains as well as carboxylic groups (COO−), thus displaying higher molecular mass and hydrophilicity, are more efficient. On the other hand, the acrylic acid derivatives, with shorter backbones and side chains and without carboxylic groups, appear less efficient. It was also proven that the maleic-based superplasticizers slow the hydration process down to a much greater extent than acrylic acid-derived superplasticizers.
Inżynieria i Budownictwo, 2007
MATEC web of conferences, 2018
The study presents the state of knowledge regarding physical and chemical properties, as well as ... more The study presents the state of knowledge regarding physical and chemical properties, as well as trends for application of fly ashes from combustion in fluidized bed boilers in building materials. Clinker-slagash based binders were tested that contained up to 40 mass % of fly ashes from combustion in fluidized bed boilers. It was demonstrated that fluidized bed combustion fly ashes (FBC fly ash), apart from granular blast furnace slag, could be the ingredient of low clinker Portland cements (ca. 20% by mass). These cements, compared to CEM I Portland cement, have higher water demand and durability in the corrosive environment, and a lower compressive strength value. Based on test results of binders with various content of blast furnace slag and fly ash, the clinker-slag-ash based binder was singled out, which demonstrated the higher durability in the corrosive environment. It was found that production of clinker-slag-ash based binders was possible in the strength class 32.5 even with 30% by mass of FBC fly ash content.
Topics in Catalysis, Mar 8, 2013
Short-channel structures of triangular and sinusoidal channel cross-sectional shape were examined... more Short-channel structures of triangular and sinusoidal channel cross-sectional shape were examined experimentally to find their heat (or mass) transfer and flow friction (flow resistance) characteristics. A particular emphasis was placed on influence of the channels length (referred to its hydraulic diameter) on transport and hydrodynamic characteristics. The transport and friction properties were correlated in terms of dimensionless channel length with satisfactory accuracy. The dimensionless channel length was proved to be a key factor that determines the transport and friction coefficients. Comparison with ceramic monolith has shown possibility of using the structures in automotive catalytic converters.
Construction and Building Materials, 2012
This paper presents research results of superplasticizers effect on rheological properties of cem... more This paper presents research results of superplasticizers effect on rheological properties of cement pastes containing blast furnace slag. The percentage of slag was from 20% to 80% by mass of cement. The specific surface of slag was similar to cement according to Blaine'a but the slag contained smaller percentage of fine fraction than cement. It was found that superplasticizer addition lowers rheological parameters of cement pastes. The decrease of rheological parameters depends on fine fraction contents in cement. Various degree of fluidity of cement pastes (C3 and CEM III/A 32.5) with similar contents of slag (about 60%) results from different amount of fine fraction below 20 lm.
Zeszyty Naukowe Politechniki Gdańskiej. Budownictwo Lądowe, 2006
Budownictwo i Architektura, Sep 11, 2013
W pracy przedstawiono wyniki bada budowy strukturalnej superplastyfikatorów nowej generacji stoso... more W pracy przedstawiono wyniki bada budowy strukturalnej superplastyfikatorów nowej generacji stosowanych w technologii betonu. Badania struktury superplastyfikatorów przeprowadzono na próbkach przy wykorzystaniu chromatografii elowej (GPC) oraz fourierowskiej spektroskopii absorpcyjnej w podczerwieni (FTIR). Przedstawiono wyniki bada wp ywu tych superplastyfikatorów na w a ciwo ci reologiczne zaczynów cementowych. Wykazano, e skuteczno dzia ania superplastyfikatora (zmniejszenie lepko ci plastycznej) wzrasta z: zawarto ci polimeru superplastyfikatora w ca kowitej masie posyntezowej próbki produktu technicznego, mas molow wagowo-redni (M w) polimeru superplastyfikatora, obecno ci wolnych grup karboksylowych lub bezwodnikowych w polimerze oraz hydrofilowo ci polimeru superplastyfikatora: okre lon stosunkiem absorbancji hydrofilowych grup eterowych do hydrofobowych grup estrowych w a cuchu polimerowym. Powy sze stwierdzono dla superplastyfikatorów pochodnych kawasów: akrylowego (SP-A1 i SP-A2) i maleinowego (SP-M2 i SP-M1). Skuteczno dzia ania superplastyfikatorów maleje wraz ze wzrostem zawarto ci wolnych, nieprzereagowanych z kwasami lub bezwodnikiem poli(glikoli etylenowych) PEG. Wykazano, e superplastyfikatory pochodne bezwodnika maleinowego (SP-M1 i SP-M2) o wi kszej hydrofilowo ci (wykazanej badaniami strukturalnymi) charakteryzuj si wi ksz skuteczno ci dzia ania ni superplastyfikatory pochodne kwasu akrylowego (SP-A1 i SP-A2).
Construction and Building Materials, Jun 1, 2013