Analiet Calvo Valdés, Marcelo H. F. Medeiros, G. Macioski
O objetivo do trabalho foi avaliar a eficácia de um sensor galvânico de múltiplos eletrodos na detecção da probabilidade de corrosão em prismas armados de concreto submetidos a ciclos de secagem e molhagem em uma solução de NaCl. Se analisaram as leituras de potencial de corrosão (Ecorr) obtidas por meio de um eletrodo de referência de cobre sulfato de cobre (Cu/CuSO4) com as leituras de corrente galvânica (Igal) e potencial galvânico (Epar). O sensor desenvolvido apresentou sensibilidade para detectar a frente de cloretos e prever a possibilidade de corrosão das armaduras. As grandezas Ecorr, Epar e Igal apresentaram comportamentos distintos como parâmetro de monitoramento da corrosão.
{"title":"Sensor de corrosão para monitoramento de estruturas de concreto armado: Testes em corpos de prova de concreto armado","authors":"Analiet Calvo Valdés, Marcelo H. F. Medeiros, G. Macioski","doi":"10.21041/ra.v11i3.529","DOIUrl":"https://doi.org/10.21041/ra.v11i3.529","url":null,"abstract":"O objetivo do trabalho foi avaliar a eficácia de um sensor galvânico de múltiplos eletrodos na detecção da probabilidade de corrosão em prismas armados de concreto submetidos a ciclos de secagem e molhagem em uma solução de NaCl. Se analisaram as leituras de potencial de corrosão (Ecorr) obtidas por meio de um eletrodo de referência de cobre sulfato de cobre (Cu/CuSO4) com as leituras de corrente galvânica (Igal) e potencial galvânico (Epar). O sensor desenvolvido apresentou sensibilidade para detectar a frente de cloretos e prever a possibilidade de corrosão das armaduras. As grandezas Ecorr, Epar e Igal apresentaram comportamentos distintos como parâmetro de monitoramento da corrosão.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77192836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aims to identify, map, and quantify the external mortar render (EMR) defects of 22 multi-storey buildings located in the Fernandópolis city, Brazil. Incidence (M-INC) and intensity (M-INT) methods were used to quantify the building defect (BD) of five typified facade regions: continuous wall (1-OCW), around openings (2-OOP), top of parapets and eaves (3-TOP), below balconies, soffits or ledges (4-BCE), and on corners and edges (5-OCE). In addition, three degradation pattern maps were created. We observed 4351 and 481 BDs by M-INT and M-INC, respectively. The most frequent problems were stains and cracks. The most affected regions by M-INT were 2-OOP (34.5%), 1-OCW (23.3%), and 4-BCP (21.6%) while by M-INC were 1-OCW (39.9%), 3- TOP (29.3%), and 2-OOP (16.6%).
{"title":"Mapping External Mortar Render (RAF) defects: case study in multi-storey residential buildings","authors":"R. Dias, L. Pagoto, N. Tsutsumoto, C. Fioriti","doi":"10.21041/ra.v11i3.538","DOIUrl":"https://doi.org/10.21041/ra.v11i3.538","url":null,"abstract":"This study aims to identify, map, and quantify the external mortar render (EMR) defects of 22 multi-storey buildings located in the Fernandópolis city, Brazil. Incidence (M-INC) and intensity (M-INT) methods were used to quantify the building defect (BD) of five typified facade regions: continuous wall (1-OCW), around openings (2-OOP), top of parapets and eaves (3-TOP), below balconies, soffits or ledges (4-BCE), and on corners and edges (5-OCE). In addition, three degradation pattern maps were created. We observed 4351 and 481 BDs by M-INT and M-INC, respectively. The most frequent problems were stains and cracks. The most affected regions by M-INT were 2-OOP (34.5%), 1-OCW (23.3%), and 4-BCP (21.6%) while by M-INC were 1-OCW (39.9%), 3- TOP (29.3%), and 2-OOP (16.6%).","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82008436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this paper is to present an evaluation of different types of cement and the incidence of Delayed Ettringite Formation (DEF) through mortar composites cast in the laboratory and exposed to a high curing temperature over a 12-month study period. DEF represents one of the types of Internal Sulfate Attacks (ISA) related to an expansive chemical reaction that occurs inside of concrete involving the sulfates from cement. Experiments involved the assessment of expansions, compressive and tensile strengths as well as microstructural characteristics over time. It was observed that tests performed on mortars and with a specific mix required an extended evaluation period to distinguish the behaviors. Furthermore, high early-strength cement featured the worst binder when faced with DEF.
{"title":"Behavior of mortars with different types of cement when induced to Delayed Ettringite Formation (DEF)","authors":"F. Tiecher, Marinês Langoski, N. Hasparyk","doi":"10.21041/ra.v11i3.537","DOIUrl":"https://doi.org/10.21041/ra.v11i3.537","url":null,"abstract":"The purpose of this paper is to present an evaluation of different types of cement and the incidence of Delayed Ettringite Formation (DEF) through mortar composites cast in the laboratory and exposed to a high curing temperature over a 12-month study period. DEF represents one of the types of Internal Sulfate Attacks (ISA) related to an expansive chemical reaction that occurs inside of concrete involving the sulfates from cement. Experiments involved the assessment of expansions, compressive and tensile strengths as well as microstructural characteristics over time. It was observed that tests performed on mortars and with a specific mix required an extended evaluation period to distinguish the behaviors. Furthermore, high early-strength cement featured the worst binder when faced with DEF.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79324218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lucas Vitoretti Dias, Silvete Mari Soares, José Américo Alves Salvador Filho, F. S. Ferreira
O pó de vidro incorporado ao concreto convencional vem sendo estudado em relação à sua influência na resistência mecânica e durabilidade. Este trabalho visa avaliar a durabilidade de compósitos cimentícios de ultra alto desempenho (CCUAD) com substituição parcial do cimento por vidro finamente moído, por meio do ensaio de migração de cloretos utilizando o método da NT Build 492. Para tanto foram moldados corpos de prova com teores de pó de vidro de 0%, 10%, 20%, 30% e 50% em relação ao volume de cimento e a avaliação foi feita na idade de 28 dias. Os resultados indicam que, em teores baixos, o pó de vidro não prejudica as propriedades dos compósitos e em teores mais altos os compósitos mantêm boas características mecânicas e de durabilidade.
{"title":"Avaliação da migração de cloretos em compósitos cimentícios de ultra alto desempenho com pó de vidro","authors":"Lucas Vitoretti Dias, Silvete Mari Soares, José Américo Alves Salvador Filho, F. S. Ferreira","doi":"10.21041/ra.v11i2.512","DOIUrl":"https://doi.org/10.21041/ra.v11i2.512","url":null,"abstract":"O pó de vidro incorporado ao concreto convencional vem sendo estudado em relação à sua influência na resistência mecânica e durabilidade. Este trabalho visa avaliar a durabilidade de compósitos cimentícios de ultra alto desempenho (CCUAD) com substituição parcial do cimento por vidro finamente moído, por meio do ensaio de migração de cloretos utilizando o método da NT Build 492. Para tanto foram moldados corpos de prova com teores de pó de vidro de 0%, 10%, 20%, 30% e 50% em relação ao volume de cimento e a avaliação foi feita na idade de 28 dias. Os resultados indicam que, em teores baixos, o pó de vidro não prejudica as propriedades dos compósitos e em teores mais altos os compósitos mantêm boas características mecânicas e de durabilidade.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"29 1","pages":"61-75"},"PeriodicalIF":0.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81303599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Flores-Nicolás, M. Flores-Nicolás, J. Uruchurtu-Chavarín
The corrosion of reinforced concrete without and with the addition of graphite powder with low carbon content was evaluated. Phase identification processes and physical-electrochemical properties of the concrete were analyzed using X-ray diffraction techniques (XRD), scanning electron microscopy (SEM), half-cell potential, electrochemical noise (EN) and linear polarization resistance (LPR). Samples were studied for 168 days in saline solution. The results show that, when adding graphite powder in an amount of 2.5% by weight of cement, the compressive strength increased if compared with the control sample. The electrochemical tests show that the higher the level of graphite replacement, the higher the level of corrosion in concrete.
{"title":"Corrosion effect on reinforced concrete with the addition of graphite powder and its evaluation on physical-electrochemical properties","authors":"A. Flores-Nicolás, M. Flores-Nicolás, J. Uruchurtu-Chavarín","doi":"10.21041/ra.v11i1.501","DOIUrl":"https://doi.org/10.21041/ra.v11i1.501","url":null,"abstract":"The corrosion of reinforced concrete without and with the addition of graphite powder with low carbon content was evaluated. Phase identification processes and physical-electrochemical properties of the concrete were analyzed using X-ray diffraction techniques (XRD), scanning electron microscopy (SEM), half-cell potential, electrochemical noise (EN) and linear polarization resistance (LPR). Samples were studied for 168 days in saline solution. The results show that, when adding graphite powder in an amount of 2.5% by weight of cement, the compressive strength increased if compared with the control sample. The electrochemical tests show that the higher the level of graphite replacement, the higher the level of corrosion in concrete.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81162514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laura Vaca Arciga, Dulce Cruz Moreno, Gerardo Del Jesús Fajardo San Miguel, Ricardo Orozco Cruz, Francisco Tienda Resendez
This study aims to evaluate the use of silicon base (NS) and functionalized (NF) nanoparticles as emerging preventive surface treatment (ST) in reinforced concrete specimens. The specimens were fabricated with a water/cement (w/c) of 0.65 and subjected to a previous aging period through exposure to CO2. Subsequently, two different variants of the treatment were applied by spraying (using a 0.1% dispersion of nanoparticles in water) and then re-applied to carbonation. The carbonation depth and contact angle results indicate that there is an influence between the degree of aging and the efficiency of each treatment.
{"title":"Use of nano-SiO2 as a preventive maintenance surface treatment in concrete aged by carbonation","authors":"Laura Vaca Arciga, Dulce Cruz Moreno, Gerardo Del Jesús Fajardo San Miguel, Ricardo Orozco Cruz, Francisco Tienda Resendez","doi":"10.21041/ra.v10i3.487","DOIUrl":"https://doi.org/10.21041/ra.v10i3.487","url":null,"abstract":"This study aims to evaluate the use of silicon base (NS) and functionalized (NF) nanoparticles as emerging preventive surface treatment (ST) in reinforced concrete specimens. The specimens were fabricated with a water/cement (w/c) of 0.65 and subjected to a previous aging period through exposure to CO2. Subsequently, two different variants of the treatment were applied by spraying (using a 0.1% dispersion of nanoparticles in water) and then re-applied to carbonation. The carbonation depth and contact angle results indicate that there is an influence between the degree of aging and the efficiency of each treatment.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83453329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alejandro Duran Herrera, J. A. Canul-Polanco, Rogelio Dávila-Pompermaye, L. G. López-Yépez, P. Valdez-Tamez
In this research, the synergetic effect of a super-absorbent polymer in combination with a calcium nitrite corrosion inhibitor were evaluated as a combined technology to improve concrete durability in High Performance Concrete. For this purpose, Portland cement mortars with a water/cement ratio of 0.4 and a substitution of 9.5% of cement by silica fume were produced. The effect of this technologies was evaluated by measuring the following parameters: autogenous and drying shrinkage, surface electrical resistivity and the non-steady-state chloride migration coefficient. The results indicate that the synergistic effect of SAP + CNI improves autogenous shrinkage and surface electrical resistivity.
{"title":"Synergetic effect of a super-absorbent polymer and a calcium nitrite corrosion inhibitor in high performance concrete durability","authors":"Alejandro Duran Herrera, J. A. Canul-Polanco, Rogelio Dávila-Pompermaye, L. G. López-Yépez, P. Valdez-Tamez","doi":"10.21041/ra.v10i2.450","DOIUrl":"https://doi.org/10.21041/ra.v10i2.450","url":null,"abstract":"In this research, the synergetic effect of a super-absorbent polymer in combination with a calcium nitrite corrosion inhibitor were evaluated as a combined technology to improve concrete durability in High Performance Concrete. For this purpose, Portland cement mortars with a water/cement ratio of 0.4 and a substitution of 9.5% of cement by silica fume were produced. The effect of this technologies was evaluated by measuring the following parameters: autogenous and drying shrinkage, surface electrical resistivity and the non-steady-state chloride migration coefficient. The results indicate that the synergistic effect of SAP + CNI improves autogenous shrinkage and surface electrical resistivity.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80709511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Bhonge, Pradeep Dalwi, Jayant V. Kulkarni, S. Manjrekar
This paper describes the rehabilitation proposal, methodology of evaluation of distress and likely remedial measures for 100 years old steel bridge on Ulhas river, near Mumbai. The bridge is constructed in year 1914 during British era apparently now heritage bridge as it was constructed with unique structural arrangement of jack arch decking and warren truss girder with verticals. After structural audit in 2000, it revealed the deterioration of steel parts and concrete initiated long back because of humid atmosphere and pollution in the area. Durgadee bridge showed various signs of bridge distress like major cracks in masonry abutments, heavy corrosion of Mild Steel (MS) structural members, non -functioning of expansion joints and bearings, failure of jack arch roof plates, de-bonding of concrete and exposed reinforcement etc. Paper discusses recommendations for rehabilitation and corrosion protection.
{"title":"Recommendations for rehabilitation and corrosion protection of a 100-year-old steel bridge (Durgadee) across heavily polluted river near Mumbai, India","authors":"S. Bhonge, Pradeep Dalwi, Jayant V. Kulkarni, S. Manjrekar","doi":"10.21041/ra.v10i2.476","DOIUrl":"https://doi.org/10.21041/ra.v10i2.476","url":null,"abstract":"This paper describes the rehabilitation proposal, methodology of evaluation of distress and likely remedial measures for 100 years old steel bridge on Ulhas river, near Mumbai. The bridge is constructed in year 1914 during British era apparently now heritage bridge as it was constructed with unique structural arrangement of jack arch decking and warren truss girder with verticals. After structural audit in 2000, it revealed the deterioration of steel parts and concrete initiated long back because of humid atmosphere and pollution in the area. Durgadee bridge showed various signs of bridge distress like major cracks in masonry abutments, heavy corrosion of Mild Steel (MS) structural members, non -functioning of expansion joints and bearings, failure of jack arch roof plates, de-bonding of concrete and exposed reinforcement etc. Paper discusses recommendations for rehabilitation and corrosion protection.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78795204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Briceño-Mena, M. Balancán-Zapata, Pedro Castro Borges
The passivation process quality was studied considering polarization periodicity, passivation consolidation parameters, and data processing. Passivation process quality in steel reinforcement affects a structure’s planned future service life. Some research has addressed this phenomenon, but its study is complicated by the limits of analog-era data, dispersion in corrosion rate data, and their interpretation. Two series of small reinforced concrete specimens were built using two water/cement ratios and two curing/storage combinations and exposed to the marine environment. Polarization periodicity did not affect passivation/depassivation during passivation but on the data processing. The curing and storage process influenced the tendency towards depassivation. Post-curing storage type affected the cumulative corrosion rate from 1 to 5 μA*day/cm2; this is equivalent to the margin of uncertainty in interpretation.
{"title":"Passivation process quality in reinforced concrete: effects of polarization periodicity and passivation consolidation parameters on data processing","authors":"J. Briceño-Mena, M. Balancán-Zapata, Pedro Castro Borges","doi":"10.21041/ra.v10i2.466","DOIUrl":"https://doi.org/10.21041/ra.v10i2.466","url":null,"abstract":"The passivation process quality was studied considering polarization periodicity, passivation consolidation parameters, and data processing. Passivation process quality in steel reinforcement affects a structure’s planned future service life. Some research has addressed this phenomenon, but its study is complicated by the limits of analog-era data, dispersion in corrosion rate data, and their interpretation. Two series of small reinforced concrete specimens were built using two water/cement ratios and two curing/storage combinations and exposed to the marine environment. Polarization periodicity did not affect passivation/depassivation during passivation but on the data processing. The curing and storage process influenced the tendency towards depassivation. Post-curing storage type affected the cumulative corrosion rate from 1 to 5 μA*day/cm2; this is equivalent to the margin of uncertainty in interpretation.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"704 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74759666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an approach to evaluate residual capacity of fire-damaged concrete structures. The approach involves capturing response in three stages; namely, structural response at ambient conditions (prior to fire exposure), thermo-mechanical response during fire exposure, and post-fire residual response after cooling down of the structural member. The proposed approach is implemented in a comprehensive numerical model developed in the finite element computer program ABAQUS for specifically evaluating residual capacity of an RC beam after exposure to different fire scenarios. Predictions from the numerical model are utilized to highlight importance of each stage of analysis in evaluating realistic residual capacity of fire damaged concrete members.
{"title":"A numerical approach for evaluating residual capacity of fire damaged concrete members","authors":"V. Kodur, A. Agarawal","doi":"10.21041/ra.v10i2.483","DOIUrl":"https://doi.org/10.21041/ra.v10i2.483","url":null,"abstract":"This paper presents an approach to evaluate residual capacity of fire-damaged concrete structures. The approach involves capturing response in three stages; namely, structural response at ambient conditions (prior to fire exposure), thermo-mechanical response during fire exposure, and post-fire residual response after cooling down of the structural member. The proposed approach is implemented in a comprehensive numerical model developed in the finite element computer program ABAQUS for specifically evaluating residual capacity of an RC beam after exposure to different fire scenarios. Predictions from the numerical model are utilized to highlight importance of each stage of analysis in evaluating realistic residual capacity of fire damaged concrete members.","PeriodicalId":21260,"journal":{"name":"Revista ALCONPAT","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90738943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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