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
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
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2010
The pape r briefly presents the res ults of expe rime nta l resea rch on the influe nce of us ing... more The pape r briefly presents the res ults of expe rime nta l resea rch on the influe nce of us ing zinc hot dip ga lvanized re bar on the durability of reinforced concrete. For this purpos e, the loss of adhe rence be tween the reba r and the concre te matrix was determ ined, as well as the reduction of resista nce to s plitting due to acce le rated corrosion of sam ples of hot dip galvanize d re bar vs. s teel not prote cte d agains t corrosion. Using e lectrochem ica l a nalysis technique s (chrono-a mpe rometry, linear polariza tion, electrochemical impeda nce s pectros copy) the kine tics a nd me cha nism of the corrosion of the reba r in the re inforced concrete due to the action of chlorine ions was studied. The results prove a lowe r speed a nd bette r res is tance to corros ion of yinc hot dip galvanize d reba r, leading to an increase d lifetime of reinforced concre te s tructures.
The circular economy (CE) and the precautionary principle (PP) are two current and contemporary n... more The circular economy (CE) and the precautionary principle (PP) are two current and contemporary notions; however, they are far from being sufficiently explored and exploited, since each is considered questionable in part. Sensing a niche at the conceptual and scientific research level regarding the unitary approaches of the CE and PP, we carried out a parallel analysis of the notions of the CE and PP with the aim of evaluating and identifying areas of manifestation and interaction. By superimposing the two concepts in feasible situations and analyzing one notion in connection with the other, within the presented examples, the particularities of the CE–PP manifestation were obtained, as well as the consequences of the non-uniform application of the mentioned factors. Also, the results of the research support the hypothesis of the compatibility between the CE and PP in certain cases and attest to the usefulness of the PP in fulfilling the wishes of the CE. Despite the generally parall...
International Multidisciplinary Scientific GeoConference SGEM .., Jun 20, 2017
Development of Fibre Engineered Cementitious Materials with Self-Healing Capacity (SH-FECM) was a... more Development of Fibre Engineered Cementitious Materials with Self-Healing Capacity (SH-FECM) was an important goal of the recent research programmes conducted in NIRD "URBAN-INCERC" Cluj-Napoca Branch. Several theoretical and experimental studies were performed in order to improve the composites, considering both, fresh and hardened state properties and also the performance as filling material of the narrow spaces at the beam to column interface within the Hybrid spatial joint model [1]. Present studies are focused in optimising the already developed mixtures regarding several aspects: the self-compacting behaviour of the fresh composites, considering the increased risk of "balling" effect when using 2% (of volume) of polymeric fibres as disperse reinforcement of the cementitious matrix, bleeding control during and after the mixes sequences by using supplementary powder addition, evaluation of the mixes when using a combination of two distinct types of polypropylene fibres, and development of controlled multiple cracks under loading, etc. The present paper offers the first results regarding the performance of the cement based composites, namely the fresh state self-compacting effect and also the flexural and compressive strengths at 7 and 28 days of age. Initial conclusions when replacing the traditional silica sand as aggregate of initial mixes with regular sand (0/1 mm fraction) are also considered. The Self-Healing potential of the mixes will be evaluated further on, ensuring the complete range of characteristics related to durability improving, repair and maintenance cost reduction and superior structural performance, in the context of the expected features of the sustainable development.
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
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
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
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2019
The process of application of concrete and mortar by shotcrete was invented in the US at the begi... more The process of application of concrete and mortar by shotcrete was invented in the US at the beginning of the 20th century. In 1907, the American Carl Akeley used this method to repair the facade of the Columbian Museum in Chicago (the old Palace of Fine Arts of the World's Columbian Exhibition). In 1911, Carl Akeley received a patent for the "cement gun". At present, the shotcrete is used both for new construction and repair / rehabilitation of old buildings. The aim of this study was to present, analyse and synthesise the current references existing in the literature, presenting the two currently used methods for obtaining shotcrete: dry and wet.
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
Urban buildings are subject to deterioration and degradation due to the action of external factor... more Urban buildings are subject to deterioration and degradation due to the action of external factors, air pollutants, water, compounds resulting from fuelcombustion used for heating and transportation, etc. Research on self-cleaning cementitious materials is developing at fast pace and contributes to the high interest in the industry in the decrease of evnironmental pollution, which is of real interest. The aim of this paper is to highlight the influence of the addition of TiO2 nanoparticles on the self-cleaning ability of cementitious materials, under staining with an aqueous solution of a rodamina B, followed by exposures to the action of UV rays, followed by artificial rain cycles and to determine the physico-mechanical properties of the material, as well as the white dregree of the samples and their self-cleaning. Based on experimental research results it can be said that the white degree of the samples increased with the increase of the TiO2 amount in the mixtures. Several other factors such as the intensity of the UV light also affected the self-cleaning capacity of the samples, better results being recorded for higher UVA intensity. The TiO2 amount in the mixtures also influences fresh and hardened state properties of the material such as setting time, apparent density, water absorbtion and porosity of the material. It can therefore be said that it is necessary to identify an optimal range of TiO2 nanopraticles concentration in the cementitious matrix, in order to obtain the maximum cumulative benefits in terms of self-cleaning capacity, physico-mechanical properties and costs.
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
DOAJ (DOAJ: Directory of Open Access Journals), Jul 1, 2014
This paper presents a comparative study on the mechanical performance of beech and ash wood lamin... more This paper presents a comparative study on the mechanical performance of beech and ash wood laminated panels. Within the experimental study the bending strength, bending modulus of elasticity and the bonding characteristics to gluing (bonding quality) were analyzed. The experimental results emphasized the influence of the type of wood, the panel thickness, the effect on the bending strength, respectively on the gluing quality of the direction of the wood lamellas in relation with the mechanical load (direction of cutting specimens). It can be said that the use of hardwood meets the needs and demands of the construction area, but it's necessary a careful analysis of the requests that occur mainly at the site, thus an optimal direction of the wooden glued lamellas can be chosen. Laminated wood panels are a product with real physical and mechanical qualities, which can be successfully used to obtain construction elements that are bringing benefits to environmental quality of living areas.
This research investigates the feasibility of developing clay composites using natural materials ... more This research investigates the feasibility of developing clay composites using natural materials and incorporating waste by-products suitable for plastering diverse support structures. The study identified a versatile composition suitable for a wide range of support materials and explored the potential of revaluing industrial waste and by-products by reintegrating them into the Circular Economy. The experimental investigation outlines the process of evaluating the influence of different raw materials on the performance of the clay composite. The findings confirm that using limestone sludge and fly ash as additives to clay contributes to reducing axial shrinkage and increasing mechanical strengths, respectively. The optimal percentage of additives for the clay used are identified and provided. Using hydraulic lime as a partial substitute for clay reduces the apparent density of dried clay composites, axial shrinkage, and fissures formation while improving adhesion to the substrate. I...
Worldwide, the need for thermal insulation materials used to increase the energy performance of b... more Worldwide, the need for thermal insulation materials used to increase the energy performance of buildings and ensure indoor thermal comfort is constantly growing. There are several traditional, well-known and frequently used thermal insulation materials on the building materials market, but there is a growing trend towards innovative materials based on agro-industrial waste. This paper analyses the performance of 10 such innovative thermal insulation materials obtained by recycling cellulosic and/or animal waste, using standardised testing methods. More precisely, thermal insulation materials based on the following raw materials were analysed: cellulose acetate, cigarette filter manufacturing waste; cellulose acetate, cigarette filter manufacturing waste and cigarette paper waste; cellulose acetate, waste from cigarette filter manufacturing, waste cigarette paper and waste aluminised paper; cellulose from waste paper (two types made by two independent manufacturers); wood fibres; ce...
European Journal of Materials Science and Engineering
As research regarding the production and optimization of geopolymer materials is constantly incre... more As research regarding the production and optimization of geopolymer materials is constantly increasing and is fundamentally motivated by the need, identified both in the global ecological context and at national level, new materials can be developed using this type of binder. Sustainable consumption of resources, focuses on the capitalization of existing waste and prevention of generating new ones, therefore adopting the Sustainable Development principles. The increase in the utilization of sand from rivers for various construction purposes, which also disturbs the environment can be considered another damaging factor for the environment. Recycling of garnets and their use as replacement for sand aggregates could provide an ecological solution for the production of the alkali-activated fly ash-based geopolymer binders. The aim of this paper is to present preliminary results regarding the use of spent garnet as replacement for sand aggregates in the production of alkali-activated fly...
Starting from the context of the principles of Sustainable Development and Circular Economy conce... more Starting from the context of the principles of Sustainable Development and Circular Economy concepts, the paper presents a synthesis of research in the field of the development of materials of interest, such as cementitious composites or alkali-activated geopolymers. Based on the reviewed literature, the influence of compositional or technological factors on the physical-mechanical performance, self-healing capacity and biocidal capacity obtained was analyzed. The inclusion of TiO2 nanoparticles in the matrix increase the performances of cementitious composites, producing a self-cleaning capacity and an anti-microbial biocidal mechanism. As an alternative, the self-cleaning capacity can be achieved through geopolymerization, which provides a similar biocidal mechanism. The results of the research carried out indicate the real and growing interest for the development of these materials but also the existence of some elements still controversial or insufficiently analyzed, therefore c...
In a time when the attention paid to identifying the possibilities of reducing problems due to ur... more In a time when the attention paid to identifying the possibilities of reducing problems due to urban pollution is increasing, the construction industry has a lot to gain if it aligns itself with the new trends of sustainable development in the field. In this context, the objective of obtaining a concrete with self-healing properties of cracks is more than appropriate, becoming a sustainable alternative for reducing the maintenance costs of transport infrastructure by increasing their operating time and by decreasing the need for the volume of repair and maintenance works, thus indirectly contributing to the reduction of environmental pollution. Preliminary results obtained using a cementitious composite with waterproofing admixture content by mass crystallization are encouraging by identifying the existence of an autonomous healing degree (closure of cracks with average opening 20-40 µm) in a proportion of at least 65% after only 96 hours of exposure in a wet-dry environment, respec...
Constructii: Journal of Civil Engineering Research, Feb 19, 2020
Sometimes there are reinforced concrete structures for which conventional computational methods a... more Sometimes there are reinforced concrete structures for which conventional computational methods are not sufficient to demonstrate their intended use. In-situ tests are conclusive to determine the ability of a structure to support additional loads, to determine its safety in the event of some design or construction deficiencies, degradation, or lack of design data. Thus, in-situ analysis validates the theoretical design approaches, in order to obtain data on the behavior of the studied elements. The aim of this paper is to present the groundwork and objectives of in-situ testing of reinforced concrete elements of buildings, with a view to possible structural assessments and to present the methods for carrying out the tests.
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
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
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2010
The pape r briefly presents the res ults of expe rime nta l resea rch on the influe nce of us ing... more The pape r briefly presents the res ults of expe rime nta l resea rch on the influe nce of us ing zinc hot dip ga lvanized re bar on the durability of reinforced concrete. For this purpos e, the loss of adhe rence be tween the reba r and the concre te matrix was determ ined, as well as the reduction of resista nce to s plitting due to acce le rated corrosion of sam ples of hot dip galvanize d re bar vs. s teel not prote cte d agains t corrosion. Using e lectrochem ica l a nalysis technique s (chrono-a mpe rometry, linear polariza tion, electrochemical impeda nce s pectros copy) the kine tics a nd me cha nism of the corrosion of the reba r in the re inforced concrete due to the action of chlorine ions was studied. The results prove a lowe r speed a nd bette r res is tance to corros ion of yinc hot dip galvanize d reba r, leading to an increase d lifetime of reinforced concre te s tructures.
The circular economy (CE) and the precautionary principle (PP) are two current and contemporary n... more The circular economy (CE) and the precautionary principle (PP) are two current and contemporary notions; however, they are far from being sufficiently explored and exploited, since each is considered questionable in part. Sensing a niche at the conceptual and scientific research level regarding the unitary approaches of the CE and PP, we carried out a parallel analysis of the notions of the CE and PP with the aim of evaluating and identifying areas of manifestation and interaction. By superimposing the two concepts in feasible situations and analyzing one notion in connection with the other, within the presented examples, the particularities of the CE–PP manifestation were obtained, as well as the consequences of the non-uniform application of the mentioned factors. Also, the results of the research support the hypothesis of the compatibility between the CE and PP in certain cases and attest to the usefulness of the PP in fulfilling the wishes of the CE. Despite the generally parall...
International Multidisciplinary Scientific GeoConference SGEM .., Jun 20, 2017
Development of Fibre Engineered Cementitious Materials with Self-Healing Capacity (SH-FECM) was a... more Development of Fibre Engineered Cementitious Materials with Self-Healing Capacity (SH-FECM) was an important goal of the recent research programmes conducted in NIRD "URBAN-INCERC" Cluj-Napoca Branch. Several theoretical and experimental studies were performed in order to improve the composites, considering both, fresh and hardened state properties and also the performance as filling material of the narrow spaces at the beam to column interface within the Hybrid spatial joint model [1]. Present studies are focused in optimising the already developed mixtures regarding several aspects: the self-compacting behaviour of the fresh composites, considering the increased risk of "balling" effect when using 2% (of volume) of polymeric fibres as disperse reinforcement of the cementitious matrix, bleeding control during and after the mixes sequences by using supplementary powder addition, evaluation of the mixes when using a combination of two distinct types of polypropylene fibres, and development of controlled multiple cracks under loading, etc. The present paper offers the first results regarding the performance of the cement based composites, namely the fresh state self-compacting effect and also the flexural and compressive strengths at 7 and 28 days of age. Initial conclusions when replacing the traditional silica sand as aggregate of initial mixes with regular sand (0/1 mm fraction) are also considered. The Self-Healing potential of the mixes will be evaluated further on, ensuring the complete range of characteristics related to durability improving, repair and maintenance cost reduction and superior structural performance, in the context of the expected features of the sustainable development.
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
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
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
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2019
The process of application of concrete and mortar by shotcrete was invented in the US at the begi... more The process of application of concrete and mortar by shotcrete was invented in the US at the beginning of the 20th century. In 1907, the American Carl Akeley used this method to repair the facade of the Columbian Museum in Chicago (the old Palace of Fine Arts of the World's Columbian Exhibition). In 1911, Carl Akeley received a patent for the "cement gun". At present, the shotcrete is used both for new construction and repair / rehabilitation of old buildings. The aim of this study was to present, analyse and synthesise the current references existing in the literature, presenting the two currently used methods for obtaining shotcrete: dry and wet.
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
Urban buildings are subject to deterioration and degradation due to the action of external factor... more Urban buildings are subject to deterioration and degradation due to the action of external factors, air pollutants, water, compounds resulting from fuelcombustion used for heating and transportation, etc. Research on self-cleaning cementitious materials is developing at fast pace and contributes to the high interest in the industry in the decrease of evnironmental pollution, which is of real interest. The aim of this paper is to highlight the influence of the addition of TiO2 nanoparticles on the self-cleaning ability of cementitious materials, under staining with an aqueous solution of a rodamina B, followed by exposures to the action of UV rays, followed by artificial rain cycles and to determine the physico-mechanical properties of the material, as well as the white dregree of the samples and their self-cleaning. Based on experimental research results it can be said that the white degree of the samples increased with the increase of the TiO2 amount in the mixtures. Several other factors such as the intensity of the UV light also affected the self-cleaning capacity of the samples, better results being recorded for higher UVA intensity. The TiO2 amount in the mixtures also influences fresh and hardened state properties of the material such as setting time, apparent density, water absorbtion and porosity of the material. It can therefore be said that it is necessary to identify an optimal range of TiO2 nanopraticles concentration in the cementitious matrix, in order to obtain the maximum cumulative benefits in terms of self-cleaning capacity, physico-mechanical properties and costs.
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
DOAJ (DOAJ: Directory of Open Access Journals), Jul 1, 2014
This paper presents a comparative study on the mechanical performance of beech and ash wood lamin... more This paper presents a comparative study on the mechanical performance of beech and ash wood laminated panels. Within the experimental study the bending strength, bending modulus of elasticity and the bonding characteristics to gluing (bonding quality) were analyzed. The experimental results emphasized the influence of the type of wood, the panel thickness, the effect on the bending strength, respectively on the gluing quality of the direction of the wood lamellas in relation with the mechanical load (direction of cutting specimens). It can be said that the use of hardwood meets the needs and demands of the construction area, but it's necessary a careful analysis of the requests that occur mainly at the site, thus an optimal direction of the wooden glued lamellas can be chosen. Laminated wood panels are a product with real physical and mechanical qualities, which can be successfully used to obtain construction elements that are bringing benefits to environmental quality of living areas.
This research investigates the feasibility of developing clay composites using natural materials ... more This research investigates the feasibility of developing clay composites using natural materials and incorporating waste by-products suitable for plastering diverse support structures. The study identified a versatile composition suitable for a wide range of support materials and explored the potential of revaluing industrial waste and by-products by reintegrating them into the Circular Economy. The experimental investigation outlines the process of evaluating the influence of different raw materials on the performance of the clay composite. The findings confirm that using limestone sludge and fly ash as additives to clay contributes to reducing axial shrinkage and increasing mechanical strengths, respectively. The optimal percentage of additives for the clay used are identified and provided. Using hydraulic lime as a partial substitute for clay reduces the apparent density of dried clay composites, axial shrinkage, and fissures formation while improving adhesion to the substrate. I...
Worldwide, the need for thermal insulation materials used to increase the energy performance of b... more Worldwide, the need for thermal insulation materials used to increase the energy performance of buildings and ensure indoor thermal comfort is constantly growing. There are several traditional, well-known and frequently used thermal insulation materials on the building materials market, but there is a growing trend towards innovative materials based on agro-industrial waste. This paper analyses the performance of 10 such innovative thermal insulation materials obtained by recycling cellulosic and/or animal waste, using standardised testing methods. More precisely, thermal insulation materials based on the following raw materials were analysed: cellulose acetate, cigarette filter manufacturing waste; cellulose acetate, cigarette filter manufacturing waste and cigarette paper waste; cellulose acetate, waste from cigarette filter manufacturing, waste cigarette paper and waste aluminised paper; cellulose from waste paper (two types made by two independent manufacturers); wood fibres; ce...
European Journal of Materials Science and Engineering
As research regarding the production and optimization of geopolymer materials is constantly incre... more As research regarding the production and optimization of geopolymer materials is constantly increasing and is fundamentally motivated by the need, identified both in the global ecological context and at national level, new materials can be developed using this type of binder. Sustainable consumption of resources, focuses on the capitalization of existing waste and prevention of generating new ones, therefore adopting the Sustainable Development principles. The increase in the utilization of sand from rivers for various construction purposes, which also disturbs the environment can be considered another damaging factor for the environment. Recycling of garnets and their use as replacement for sand aggregates could provide an ecological solution for the production of the alkali-activated fly ash-based geopolymer binders. The aim of this paper is to present preliminary results regarding the use of spent garnet as replacement for sand aggregates in the production of alkali-activated fly...
Starting from the context of the principles of Sustainable Development and Circular Economy conce... more Starting from the context of the principles of Sustainable Development and Circular Economy concepts, the paper presents a synthesis of research in the field of the development of materials of interest, such as cementitious composites or alkali-activated geopolymers. Based on the reviewed literature, the influence of compositional or technological factors on the physical-mechanical performance, self-healing capacity and biocidal capacity obtained was analyzed. The inclusion of TiO2 nanoparticles in the matrix increase the performances of cementitious composites, producing a self-cleaning capacity and an anti-microbial biocidal mechanism. As an alternative, the self-cleaning capacity can be achieved through geopolymerization, which provides a similar biocidal mechanism. The results of the research carried out indicate the real and growing interest for the development of these materials but also the existence of some elements still controversial or insufficiently analyzed, therefore c...
In a time when the attention paid to identifying the possibilities of reducing problems due to ur... more In a time when the attention paid to identifying the possibilities of reducing problems due to urban pollution is increasing, the construction industry has a lot to gain if it aligns itself with the new trends of sustainable development in the field. In this context, the objective of obtaining a concrete with self-healing properties of cracks is more than appropriate, becoming a sustainable alternative for reducing the maintenance costs of transport infrastructure by increasing their operating time and by decreasing the need for the volume of repair and maintenance works, thus indirectly contributing to the reduction of environmental pollution. Preliminary results obtained using a cementitious composite with waterproofing admixture content by mass crystallization are encouraging by identifying the existence of an autonomous healing degree (closure of cracks with average opening 20-40 µm) in a proportion of at least 65% after only 96 hours of exposure in a wet-dry environment, respec...
Constructii: Journal of Civil Engineering Research, Feb 19, 2020
Sometimes there are reinforced concrete structures for which conventional computational methods a... more Sometimes there are reinforced concrete structures for which conventional computational methods are not sufficient to demonstrate their intended use. In-situ tests are conclusive to determine the ability of a structure to support additional loads, to determine its safety in the event of some design or construction deficiencies, degradation, or lack of design data. Thus, in-situ analysis validates the theoretical design approaches, in order to obtain data on the behavior of the studied elements. The aim of this paper is to present the groundwork and objectives of in-situ testing of reinforced concrete elements of buildings, with a view to possible structural assessments and to present the methods for carrying out the tests.
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