Internal sulfate attack - points of agreement and disagreement

2004 ◽  
Author(s):  
J. Skalny
Keyword(s):  
Sulfate Attack ◽  
Internal Sulfate Attack

Use of Raman spectroscopy to characterize the effect of nanomagnetite as an addition to Portland cement paste on mitigating internal sulfate attack

2020 ◽  
Vol 262 ◽  
pp. 120803
Author(s):  
Tassiane A. Oliveira ◽  
Igor M. Pinkoski ◽  
Mariana O.G.P. Bragança ◽  
André Assmann ◽  
Isabela C. Oliveira ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Portland Cement ◽  
Cement Paste ◽  
Sulfate Attack ◽  
Portland Cement Paste ◽  
Internal Sulfate Attack

scholarly journals Deterioration Process of Concrete Exposed to Internal Sulfate Attack

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1336 ◽  
Author(s):  
Weifeng Chen ◽  
Bei Huang ◽  
Yuexue Yuan ◽  
Min Deng
Keyword(s):  
Compressive Strength ◽  
Sulfate Attack ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Great Loss ◽  
Sulfate Ions ◽  
Coarse Aggregates ◽  
Deterioration Process ◽  
One Year ◽  
Internal Sulfate Attack

Damage to concrete structures with gypsum-contaminated aggregate occurs frequently. Aggregates in much of the southern part of China are contaminated with gypsum. Therefore, in this study, the effects of using different quantities of gypsum-contaminated aggregate on the expansion and compressive strength of concrete were investigated over a period of one year. Two groups of concrete were designed with the gypsum-contaminated aggregate containing different parts of fine and coarse aggregate, respectively. The SO3 contents were 0%, 0.5%, 1%, 1.5%, 3%, 5%, and 7% by weight of aggregate. X-ray diffraction (XRD), thermogravimetry (TG), and differential scanning calorimetry (DSC) were used to analyze the change in mineral composition over time. The microstructure was also studied by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results showed that significant expansion and great loss in compressive strength did not occur in concrete if the content of SO3 lay below 1.5% and 3% in fine and coarse aggregates, respectively. The concentration of sulfate ions in concrete was not enough to form new a phase of gypsum. During the process of internal sulfate attack, the content of gypsum decreased and the content of ettringite increased. Ettringite was the main reason for the expansion damage of concrete. Additionally, the fracture mode of internal sulfate attack on concrete was the crack extension from gypsum to paste; finally, the aggregate separated from the paste.

New kinetic model to quantify the internal sulfate attack in concrete

2013 ◽  
Vol 43 ◽  
pp. 95-104 ◽  
Author(s):  
Izelman Oliveira ◽  
Sergio H.P. Cavalaro ◽  
Antonio Aguado
Keyword(s):  
Kinetic Model ◽  
Sulfate Attack ◽  
Internal Sulfate Attack

Accelerate Thaumasite Formation in Cement-Limestone Powder Paste by Internal Adding Method

2011 ◽  
Vol 250-253 ◽  
pp. 22-27 ◽  
Author(s):  
Chang Cheng Li ◽  
Yan Yao ◽  
Ling Wang
Keyword(s):  
Magnesium Sulfate ◽  
Sodium Sulfate ◽  
Calcium Sulfate ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cement Based Materials ◽  
Internal Sulfate Attack

Cement-limestone powder pastes added with 10% magnesium sulfate, sodium sulfate, and calcium sulfate respectively were stored in water at (5±2) °C to accelerate thaumasite formation. The pastes were inspected visually at intervals. And the formation of thaumasite was identified and confirmed by X-ray diffraction (XRD), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The results show that internal adding sulfate in cement-limestone powder paste is an efficient way to accelerate thaumasite formation, and the accelerated effect is magnesium sulfate> sodium sulfate> calcium sulfate. Cement-limestone paste containing 10% magnesium sulfate totally turns into grey-white mushy materials after 6 months immersion, and products are mainly thaumasite and gypsum. In addition, the amount of thaumasite increases along with time of internal sulfate attack in 15 months. XRD, IR, and NMR are powerful and reliable tools for identification of thaumasite in cement-based materials.

scholarly journals Deterioration Caused By Sulfide-Bearing Aggregates: Performance Test Development

2021 ◽  
Author(s):  
Bradley Maguire
Keyword(s):  
Performance Test ◽  
Iron Sulfide ◽  
Coarse Aggregate ◽  
Test Methods ◽  
Sulfate Attack ◽  
Ettringite Formation ◽  
Heating And Cooling ◽  
Friedel’S Salt ◽  
Lime Solution ◽  
Internal Sulfate Attack

Recently in Quebec Canada, concrete structures suffered very rapid deterioration within 3 to 5 years of construction. The deterioration was caused by an iron sulfide, namely pyrrhotite, in the coarse aggregate that suffered oxidation inside concrete and promoted sulfate attack; indicated by the presence of ferric oxyhydroxides (“rust”), gypsum, ettringite, and thaumasite. The goal of the current work was to reproduce this reaction under accelerated laboratory conditions, in progression of a performance test. Conditions to promote pyrrhotite oxidation and internal sulfate attack were provided; exposure cycles were tested with heating and cooling, and saturation in oxidizing agents or lime solution. Oxidation was induced in concrete samples, however, other mechanisms contributed to deterioration. The bleach was found to promote NaCl and Friedel’s salt formation, furthermore, it seemed to mitigate expansion from sulfate attack. Sulfoaluminate decomposition was also found to cause secondary ettringite formation. More optimization to the test methods was recommended.

Effect of crystalline admixture and polypropylene microfiber on the internal sulfate attack in Portland cement composites due to pyrite oxidation

2021 ◽  
Vol 308 ◽  
pp. 125018
Author(s):  
Mateus E.G. Dobrovolski ◽  
Guilherme S. Munhoz ◽  
Eduardo Pereira ◽  
Ronaldo A. Medeiros-Junior
Keyword(s):  
Portland Cement ◽  
Pyrite Oxidation ◽  
Sulfate Attack ◽  
Cement Composites ◽  
Internal Sulfate Attack

Investigation of damaged interior walls using synchrotron-based XPS and XANES

2015 ◽  
Vol 22 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Yingyot Poo-arporn ◽  
Surachai Thachepan ◽  
Rungtiva Palangsuntikul
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sulfate Attack ◽  
Field Exposure ◽  
Edge Structure ◽  
X Ray ◽  
Black Layer ◽  
Interior Walls ◽  
X Ray Absorption ◽  
Chemical Integrity ◽  
Internal Sulfate Attack

Evidence of internal sulfate attack in field exposure was demonstrated by the damaged interior wall of a three-year-old house situated in Nakhon Ratchasima Province, Thailand. Partial distension of the mortar was clearly observed together with an expansion of a black substance. Removal of the black substance revealed a dense black layer. This layer was only found in the vicinity of the damaged area, suggesting that this black material is possibly involved in the wall cracking. By employing synchrotron-based X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) techniques, the unknown sample was chemically identified. The S 2pand O 1sXPS results mutually indicated the existence of sulfate species in the materials collected from the damaged area. The XANES results indicated the presence of ferrous (II) sulfate, confirming sulfate-induced expansion and cracking. The sulfate attack in the present case appeared to physically affect the structure whereas the chemical integrity at the molecular level of the calcium silicate hydrate phase was retained since there was a lack of spectroscopic evidence for calcium sulfate. It was speculated that internal sulfate probably originated from the contaminated aggregates used during the construction. The current findings would be beneficial for understanding the sulfate-attack mechanism as well as for future prevention against sulfate attack during construction.

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