• Properties of alkali activated slag mortar after exposure ...

    The obtained SEM/EDS results indicated that the decomposition process of alkali activated slag mortar is responsible for the deterioration of mechanical properties after exposure to elevated temperatures with different duration times.

  • A Review on Durability of Alkali-activated System from ...

    Feb 06, 2019· 69 reported the results of alkali-activated slag mortar exposed to 5% solution of different acids within 6 months. Only slight changes were observed in the solution of citric acid, and moderate changes in nitric acid and hydrochloric acid solutions, while severe degradation was observed in sulfuric acid solution.

  • Flexural Behavior of Basalt Textile Reinforced Alkali-activated Mortar after Exposure to Elevated Temperatures : DOI: ... Due to the decomposition of epoxy resin and the deterioration of the bond between fiber and matrix, significant strength loss can be observed when the exposure temperature was higher than 600 ℃. ... the alkali-activated ...

  • Long-Term Behavior and Durability of Alkali-Activated Clay ...

    The need to increase the durability of clay-based materials, due to their inherent low strength and vulnerability in contact with water, led researchers to examine different options. In this paper, clay mortars were produced using four different activating solutions. Alkali hydroxides, alkali carbonates, and alkali silicates activating solutions were used.

  • Resistance Tests for Alkali-Activated FA GGBFS

    Oct 29, 2019· The alkali-activated GGBFS blended mortars showed a tendency to increase in mass and length and decrease in compressive strength when immersed in a magnesium sulfate solution, whereas the alkali-activated FA mortars did not show any significant di erence depending on the types of sulfate solution applied. The deterioration of alkali-activated

  • Properties of Alkali Activated Slag Mortar after Exposure ...

    The residual compressive strength of alkali activated slag mortars experienced 2-hour 400 °C exposure was 76.2 % (i.e., 54.6 MPa) of the unexposed mortar. This value was very similar to the residual compressive strength of specimens subjected to 400 °C exposure for 1 hours (i.e., 75.9 % of the strength of control specimens).

  • Deterioration and damage evaluation of rendering mortars ...

    May 06, 2009· The atmospheric deterioration of cement mortars made with limestone aggregates and exposed to urban pollutants have recently been studied by Tittarelli et al. [], who found that acid attack and gypsum formation at the expense of carbonate are the main deterioration processes taking place in the cement mortar.In addition, they find out that the inner parts of the render are formed substantially ...

  • Investigating the resistance of alkali-activated slag ...

    Investigating the resistance of alkali -activated slag mortar exposed to magnesium sulfate attack A. Allahvedi1, 2,*, H. Hashemi2 Received: May 2013, Revised: November 2014, Accepted: December 2014 Abstract This paper presents an investigation on durability of alkali-activated slag mortar against magnesium sulfate attack. To do

  • The long-term failure mechanisms of alkali-activated slag ...

    This study investigates the long-term (570 days) performance of alkali-activated slag (AAS) mortar materials exposed to combined wet-dry cycles and sodium sulphate solutions (i.e. 5 wt% and 10 wt%). Physical and mechanical characteristics of AAS mortars (i.e. visual appearance, compressive/flexural strength, mass change, capillary porosity, water sorptivity) as well as mineralogical and ...

  • Sulfate Resistance of Alkali Activated Pozzolans

    Hakkinen evaluated the sulfate resistance of both alkali activated slag cement and Portland cement. The Portland cement samples were destroyed when exposed in 10 % Na 2SO 4 solution for 2 years or immersed in 10 % MgSO 4 solution for 1 year, while the alkali activated slag cement samples survived well (Hakkinen 1987, 1986).

  • Article The Durability of One-Part Alkali-Activated Slag ...

    based deicing salts, both on one-part and two-part alkali-activated materials as defined by Luukkonen et al. [22]. The purpose of this study is to evaluate the durability of one-part alkali-activated slag-based mortars subjected to magnesium sulphate attack, exposed to freeze and thaw cycles or calcium

  • (PDF) Deterioration of alkali-activated mortars exposed to ...

    The alkali-activated slag mortars were exposed to 5% sulfuric and acetic acid solutions for 30 days. Mass change, compressive strength and microstructural changes were evaluated.

  • The Durability of One-Part Alkali-Activated Slag-Based ...

    The paper assesses the durability of one-part alkali-activated slag-based mortars (AAS) in different aggressive environments, such as calcium chloride- and magnesium sulphate-rich solutions, in comparison with traditional cementitious mortars at equal water to binder ratio. Moreover, the freezing and thawing resistance was evaluated on mortars manufactured with and without air entraining ...

  • Deterioration of mortars exposed to sulfate attack under ...

    Abstract The damage process of plain and blended cement mortars subjected to sulfate attack under electrical field was investigated in this paper. The deterioration of mortars was investigated by measuring the loss of compressive strength. To identify the changes of microstructure and mineral phases after the test, scanning electron microscopy, energy dispersive spectroscopy and X-ray ...

  • Deterioration of alkali-activated mortars exposed to ...

    Oct 20, 2018· Alkali activated mortars were exposure to natural sewer environment. • Visual and microstructural assessment was performed. • Loss in surface pH and pH within the depth was observed. • Thenardite and gypsum crystallization within the microstructure was observed. • Sulphur concentration of both alkali-activated mortars was evaluated.

  • (PDF) Leaching Resistance of Alkali-Activated Slag and Fly ...

    Finally, the results of theoretical analysis predicted that the degradation depth of alkali-activated slag/fly ash mortars exposed to sulfuric acid environment (pH ¼ 2.0) for 50 years could be ...

  • Influence of different admixtures on the mechanical and ...

    Dec 30, 2020· The residual strength of AAM mortars exposed to sulfate solution was in the range of 83–99%. However, mortars samples exposed to sulfuric acid solution underwent cracking and deterioration with the visible leaching out of binder paste accompanied with significant strength loss. ... SEM analysis shows that alkali activated mortars containing ...

  • Performance of alkali-activated slag mortars exposed to ...

    The acid resistance of 60-day cured alkali-activated slag (AAS) mortars, in comparison with Portland cement, is assessed. Specimens are exposed to hydrochloric, nitric and sulphuric acids at pH 3.0, and acetic acid (CH3COOH) at pH 4.5, for 150 days, with specimens also immersed in water as a control. Negligible changes in compressive strength are identified in Portland cement and AAS binders ...

  • (PDF) Microstructural Analysis of Geopolymer and Ordinary ...

    There were no deterioration effect on the surface for both mortars; OPC and geopolymer in figure 1. The specimen structure, and the matrix between aggregate and binder was structurally intact.As explained by many researchers of OPC scientists, the reaction of OPC with sulfuric acid can be concluded as (eq. 1-3): The formation of gypsum and ...

  • The long-term failure mechanisms of alkali-activated slag ...

    Feb 01, 2021· When AAS mortar (AAS-N5) was exposed to 5 wt% Na 2 SO 4, surface roughness was observed to increase prior to 360 days and the efflorescence was developed after 570 days of exposure. Increasing the sodium sulphate concentration to 10 wt% (AAS-N10) increased efflorescence onset and area coverage with salt crystallisation which occurred after 90 ...

  • Durability of alkali-activated materials in aggressive ...

    Oct 15, 2017· Effective passivation of steels occurs in alkali-activated fly ash mortars when exposed to external chlorides. There are no deterioration observed in alkali-activated fly ash specimens when immersed in NaCl solution for 1–2 years, . However, internal blended CaCl 2 …

  • (PDF) Performance of alkali-activated slag mortars exposed ...

    Performance of alkali-activated slag mortars exposed to acids. Download. Related Papers. Decalcification of alkali-activated slag pastes. Effect of the chemical composition of the slag. By Ruby Mejia. Effect of silicate modulus and metakaolin incorporation on …

  • Performance of alkali activated slag concrete under ...

    resulting in deterioration of the concrete layers [7]. Alkali Activated Slag (AAS) mortar exposed to 5% sulphuric acid shows severe degradation in comparison with citric acid, hydrochloric acid, and nitric acid solutions over a period of 6 months [8]. The concrete made with …

  • Deterioration of alkali-activated mortars exposed to ...

    This study aims to evaluate the performance of low calcium fly ash based geopolymer (FA-GPm) and alkali-activated slag based mortars (AASm) in an aggressive sewer environment. Specimens were extracted from field exposure, after 6 and 12 months. Visual, chemical and physical analyses were performed to evaluate the deterioration.

  • Mechanical and durability assessment of cement-based and ...

    May 10, 2021· Shi C, Krivenko PV, Roy D (2006) Alkali-activated cements and concretes. Taylor & Francis, Milton Park. Book Google Scholar 69. Ismail I et al (2013) Influence of fly ash on the water and chloride permeability of alkali-activated slag mortars and concretes. Constr Build Mater 48:1187–1201.

  • [PDF] Leaching, carbonation and chloride ingress in ...

    Exposure to 100 % CO2 atmosphere caused steel depassivation within approx. two weeks; in addition, indications of a deterioration of the mortar were observed. The results are discussed in the context of the different reaction products expected in high- and low-Ca alkali-activated binders, and the alterations caused by leaching and carbonation.

  • (PDF) Performance of alkali-activated slag mortars exposed ...

    The acid resistance of 60-day cured alkali-activated slag (AAS) mortars, in comparison with Portland cement, is assessed. Specimens are exposed to hydrochloric, nitric and sulphuric acids at pH 3 ...

  • Strength and Durability Performance of Alkali-Activated ...

    Nov 23, 2014· This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive …

  • Properties of alkali activated slag mortar after exposure ...

    The obtained SEM/EDS results indicated that the decomposition process of alkali activated slag mortar is responsible for the deterioration of mechanical properties after exposure to elevated temperatures with different duration times.

  • A Review on Durability of Alkali-activated System from ...

    Feb 06, 2019· 69 reported the results of alkali-activated slag mortar exposed to 5% solution of different acids within 6 months. Only slight changes were observed in the solution of citric acid, and moderate changes in nitric acid and hydrochloric acid solutions, while severe degradation was observed in sulfuric acid solution.

  • Flexural Behavior of Basalt Textile Reinforced Alkali-activated Mortar after Exposure to Elevated Temperatures : DOI: ... Due to the decomposition of epoxy resin and the deterioration of the bond between fiber and matrix, significant strength loss can be observed when the exposure temperature was higher than 600 ℃. ... the alkali-activated ...

  • Long-Term Behavior and Durability of Alkali-Activated Clay ...

    The need to increase the durability of clay-based materials, due to their inherent low strength and vulnerability in contact with water, led researchers to examine different options. In this paper, clay mortars were produced using four different activating solutions. Alkali hydroxides, alkali carbonates, and alkali silicates activating solutions were used.

  • Resistance Tests for Alkali-Activated FA GGBFS

    Oct 29, 2019· The alkali-activated GGBFS blended mortars showed a tendency to increase in mass and length and decrease in compressive strength when immersed in a magnesium sulfate solution, whereas the alkali-activated FA mortars did not show any significant di erence depending on the types of sulfate solution applied. The deterioration of alkali-activated

  • Properties of Alkali Activated Slag Mortar after Exposure ...

    The residual compressive strength of alkali activated slag mortars experienced 2-hour 400 °C exposure was 76.2 % (i.e., 54.6 MPa) of the unexposed mortar. This value was very similar to the residual compressive strength of specimens subjected to 400 °C exposure for 1 hours (i.e., 75.9 % of the strength of control specimens).

  • Deterioration and damage evaluation of rendering mortars ...

    May 06, 2009· The atmospheric deterioration of cement mortars made with limestone aggregates and exposed to urban pollutants have recently been studied by Tittarelli et al. [], who found that acid attack and gypsum formation at the expense of carbonate are the main deterioration processes taking place in the cement mortar.In addition, they find out that the inner parts of the render are formed substantially ...

  • Investigating the resistance of alkali-activated slag ...

    Investigating the resistance of alkali -activated slag mortar exposed to magnesium sulfate attack A. Allahvedi1, 2,*, H. Hashemi2 Received: May 2013, Revised: November 2014, Accepted: December 2014 Abstract This paper presents an investigation on durability of alkali-activated slag mortar against magnesium sulfate attack. To do

  • The long-term failure mechanisms of alkali-activated slag ...

    This study investigates the long-term (570 days) performance of alkali-activated slag (AAS) mortar materials exposed to combined wet-dry cycles and sodium sulphate solutions (i.e. 5 wt% and 10 wt%). Physical and mechanical characteristics of AAS mortars (i.e. visual appearance, compressive/flexural strength, mass change, capillary porosity, water sorptivity) as well as mineralogical and ...

  • Sulfate Resistance of Alkali Activated Pozzolans

    Hakkinen evaluated the sulfate resistance of both alkali activated slag cement and Portland cement. The Portland cement samples were destroyed when exposed in 10 % Na 2SO 4 solution for 2 years or immersed in 10 % MgSO 4 solution for 1 year, while the alkali activated slag cement samples survived well (Hakkinen 1987, 1986).

  • Article The Durability of One-Part Alkali-Activated Slag ...

    based deicing salts, both on one-part and two-part alkali-activated materials as defined by Luukkonen et al. [22]. The purpose of this study is to evaluate the durability of one-part alkali-activated slag-based mortars subjected to magnesium sulphate attack, exposed to freeze and thaw cycles or calcium

  • (PDF) Deterioration of alkali-activated mortars exposed to ...

    The alkali-activated slag mortars were exposed to 5% sulfuric and acetic acid solutions for 30 days. Mass change, compressive strength and microstructural changes were evaluated.

  • The Durability of One-Part Alkali-Activated Slag-Based ...

    The paper assesses the durability of one-part alkali-activated slag-based mortars (AAS) in different aggressive environments, such as calcium chloride- and magnesium sulphate-rich solutions, in comparison with traditional cementitious mortars at equal water to binder ratio. Moreover, the freezing and thawing resistance was evaluated on mortars manufactured with and without air entraining ...

  • Deterioration of mortars exposed to sulfate attack under ...

    Abstract The damage process of plain and blended cement mortars subjected to sulfate attack under electrical field was investigated in this paper. The deterioration of mortars was investigated by measuring the loss of compressive strength. To identify the changes of microstructure and mineral phases after the test, scanning electron microscopy, energy dispersive spectroscopy and X-ray ...

  • Deterioration of alkali-activated mortars exposed to ...

    Oct 20, 2018· Alkali activated mortars were exposure to natural sewer environment. • Visual and microstructural assessment was performed. • Loss in surface pH and pH within the depth was observed. • Thenardite and gypsum crystallization within the microstructure was observed. • Sulphur concentration of both alkali-activated mortars was evaluated.

  • (PDF) Leaching Resistance of Alkali-Activated Slag and Fly ...

    Finally, the results of theoretical analysis predicted that the degradation depth of alkali-activated slag/fly ash mortars exposed to sulfuric acid environment (pH ¼ 2.0) for 50 years could be ...

  • Influence of different admixtures on the mechanical and ...

    Dec 30, 2020· The residual strength of AAM mortars exposed to sulfate solution was in the range of 83–99%. However, mortars samples exposed to sulfuric acid solution underwent cracking and deterioration with the visible leaching out of binder paste accompanied with significant strength loss. ... SEM analysis shows that alkali activated mortars containing ...

  • Performance of alkali-activated slag mortars exposed to ...

    The acid resistance of 60-day cured alkali-activated slag (AAS) mortars, in comparison with Portland cement, is assessed. Specimens are exposed to hydrochloric, nitric and sulphuric acids at pH 3.0, and acetic acid (CH3COOH) at pH 4.5, for 150 days, with specimens also immersed in water as a control. Negligible changes in compressive strength are identified in Portland cement and AAS binders ...

  • (PDF) Microstructural Analysis of Geopolymer and Ordinary ...

    There were no deterioration effect on the surface for both mortars; OPC and geopolymer in figure 1. The specimen structure, and the matrix between aggregate and binder was structurally intact.As explained by many researchers of OPC scientists, the reaction of OPC with sulfuric acid can be concluded as (eq. 1-3): The formation of gypsum and ...

  • The long-term failure mechanisms of alkali-activated slag ...

    Feb 01, 2021· When AAS mortar (AAS-N5) was exposed to 5 wt% Na 2 SO 4, surface roughness was observed to increase prior to 360 days and the efflorescence was developed after 570 days of exposure. Increasing the sodium sulphate concentration to 10 wt% (AAS-N10) increased efflorescence onset and area coverage with salt crystallisation which occurred after 90 ...

  • Durability of alkali-activated materials in aggressive ...

    Oct 15, 2017· Effective passivation of steels occurs in alkali-activated fly ash mortars when exposed to external chlorides. There are no deterioration observed in alkali-activated fly ash specimens when immersed in NaCl solution for 1–2 years, . However, internal blended CaCl 2 …

  • (PDF) Performance of alkali-activated slag mortars exposed ...

    Performance of alkali-activated slag mortars exposed to acids. Download. Related Papers. Decalcification of alkali-activated slag pastes. Effect of the chemical composition of the slag. By Ruby Mejia. Effect of silicate modulus and metakaolin incorporation on …

  • Performance of alkali activated slag concrete under ...

    resulting in deterioration of the concrete layers [7]. Alkali Activated Slag (AAS) mortar exposed to 5% sulphuric acid shows severe degradation in comparison with citric acid, hydrochloric acid, and nitric acid solutions over a period of 6 months [8]. The concrete made with …

  • Deterioration of alkali-activated mortars exposed to ...

    This study aims to evaluate the performance of low calcium fly ash based geopolymer (FA-GPm) and alkali-activated slag based mortars (AASm) in an aggressive sewer environment. Specimens were extracted from field exposure, after 6 and 12 months. Visual, chemical and physical analyses were performed to evaluate the deterioration.

  • Mechanical and durability assessment of cement-based and ...

    May 10, 2021· Shi C, Krivenko PV, Roy D (2006) Alkali-activated cements and concretes. Taylor & Francis, Milton Park. Book Google Scholar 69. Ismail I et al (2013) Influence of fly ash on the water and chloride permeability of alkali-activated slag mortars and concretes. Constr Build Mater 48:1187–1201.

  • [PDF] Leaching, carbonation and chloride ingress in ...

    Exposure to 100 % CO2 atmosphere caused steel depassivation within approx. two weeks; in addition, indications of a deterioration of the mortar were observed. The results are discussed in the context of the different reaction products expected in high- and low-Ca alkali-activated binders, and the alterations caused by leaching and carbonation.

  • (PDF) Performance of alkali-activated slag mortars exposed ...

    The acid resistance of 60-day cured alkali-activated slag (AAS) mortars, in comparison with Portland cement, is assessed. Specimens are exposed to hydrochloric, nitric and sulphuric acids at pH 3 ...

  • Strength and Durability Performance of Alkali-Activated ...

    Nov 23, 2014· This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive …