Acid attack on geopolymer cement mortar based on waste-glass powder and calcium aluminate cement at mild concentration

Vafaei, Mostafa; Allahverdi, Ali; Dong, Peng; Bassim, Nabil

doi:10.1016/j.conbuildmat.2018.10.203

Cited by 96 publications

(35 citation statements)

References 22 publications

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“…The compressive strength of OPC-GGBFS1.5PE reduced continuously until the end of exposure for 112 days to 51.45 MPa, a 31% reduction in its original strength, with a large amount of soft expansive gypsum layer in the cementitious matrix, therefore loosening the fibre-matrix bonding strength. For the CAC-GGBFS1.5 group after acid exposure, a rapid reduction of 28% was observed from 49.23 (60 days) to 35.29 MPa (112 days); similar results were also found in [ 26 , 27 , 28 ]. This is due to the cement hydrates reacted with sulfate ions (SO 4 2− ) until the pressure exceeded the tensile strength of mortar, then cracks formed and resulted in surface cracking and spalling.…”

Section: Resultssupporting

confidence: 82%

Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack

Fan

Zhuge

et al. 2020

Materials

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Concrete wastewater infrastructures are important to modern society but are susceptible to sulfuric acid attack when exposed to an aggressive environment. Fibre-reinforced mortar has been adopted as a promising coating and lining material for degraded reinforced concrete structures due to its unique crack control and excellent anti-corrosion ability. This paper aims to evaluate the performance of polyethylene (PE) fibre-reinforced calcium aluminate cement (CAC)–ground granulated blast furnace slag (GGBFS) blended strain-hardening mortar after sulfuric acid immersion, which represented the aggressive sewer environment. Specimens were exposed to 3% sulfuric acid solution for up to 112 days. Visual, physical and mechanical performance such as water absorption ability, sorptivity, compressive and direct tensile strength were evaluated before and after sulfuric acid attack. In addition, micro-structure changes to the samples after sulfuric acid attack were also assessed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to further understand the deterioration mechanism. The results show that overall fibre-reinforced calcium aluminate cement (CAC)-based samples performed significantly better than fibre-reinforced ordinary Portland cement (OPC)-based samples as well as mortar samples in sulfuric acid solution in regard to visual observations, penetration depth, direct tensile strength and compressive reduction. Gypsum generation in the cementitious matrix of both CAC and OPC-based systems was the main reason behind the deterioration mechanism after acid attack exposure. Moreover, laboratory sulfuric acid testing has been proven for successfully screening the cementitious material against an acidic environment. This method can be considered to design the service life of concrete wastewater pipes.

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Section: Resultssupporting

confidence: 82%

Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack

Fan

Zhuge

et al. 2020

Materials

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“…Both of the alkaline environments are SR-FFA-GEO material can be used as the alternative to OPC material in civil engineering industry. However, besides the mechanical strength, the chemical resistances of OPC material are not superior due to the dissolution reaction of silicate under acid and sulfate attack [44]. Due to the inorganic calcium salts in SR, the chemical resistances of the SR-FFA-GEO mortar are unpredictable.…”

Section: Strength and Mass Changes Of Sr-ffa-geo Mortar Under Water Ementioning

confidence: 99%

Resistance of Soda Residue–Fly Ash Based Geopolymer Mortar to Acid and Sulfate Environments

et al. 2021

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The early mechanical performances of low-calcium fly ash (FFA)-based geopolymer (FFA–GEO) mortar can be enhanced by soda residue (SR). However, the resistance of SR–FFA–GEO mortar to acid or sulfate environments is unclear, owing to the various inorganic calcium salts in SR. The aim of this study was to investigate the long-term mechanical strengths of up to 360 d and evaluate the resistance of SR–FFA–GEO mortar to 5% HCl and 5% Na2SO4 environments through the losses in compressive strength and mass. Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS) and Fourier Transform Infrared Spectrometer (FTIR) experiments were conducted for the SR–FFA–GEO mortars, both before and after chemical attack, to clarify the attack mechanism. The results show that the resistances of the SR–FFA–GEO mortar with 20% SR (namely M10) to 5% HCl and 5% Na2SO4 environments are superior to those of cement mortar. The environmental HCl reacts with the calcites in SR to produce CaCl2, CO2 and H2O to form more pores under HCl attack, and the environmental Na+ cations from Na2SO4 go into Si-O-Al network structure, to further enhance the strength of mortar under Na2SO4 attack. These results provide the experimental basis for the durability optimization of SR–FFA–GEO mortars.

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“…Therefore, as can be seen in Figure 4, the mass loss of control mortars, ethyl silicate, and nanosilica mortars exposed to the same conditions of acid attack was considerably higher than that of the zinc stearate mortar. Calcium compounds in these systems react with the acid solutions, resulting in the decomposition of hydration products and increasing the total porosity, subsequently accelerating the acid attack [45,46]. However, the water-repellent admixture (zinc stearate) was able to enhance the resistance to acid environments because they reduce the affinity of capillary pore surfaces to moisture and slow down mass loss [24].…”

Section: Mass Loss Caused By Sulphuric Acid Exposurementioning

confidence: 99%

Pore Structure Degradation of Different Cement Mortars Exposed to Sulphuric Acid

et al. 2019

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Acid attack causes the deterioration of construction material surfaces. The objective of this study was to investigate the degradation of different types of cement mortar in terms of variations in pore size distribution obtained by mercury intrusion porosimetry (MIP), mass loss, and compressive strength. The mortars were manufactured with nanosilica, zinc stearate, and an ethyl silicate coating. After curing (28 days), the samples were subjected to acid exposure for 90 days, immersed ina solution (3% w/w) of sulphuric acid (H2SO4). The results indicate that the mortars showed a more refined microstructure, with a higher proportion of smaller pores (<100 nm) compared to the control mortar. The 28-day and 90-day compressive strength variations of mortars were also determined by observing pronounced reduction due to the appearance of expansive compounds responsible for microcracking.

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Acid attack on geopolymer cement mortar based on waste-glass powder and calcium aluminate cement at mild concentration

Cited by 96 publications

References 22 publications

Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack

Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack

Resistance of Soda Residue–Fly Ash Based Geopolymer Mortar to Acid and Sulfate Environments

Pore Structure Degradation of Different Cement Mortars Exposed to Sulphuric Acid

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