scholarly journals Mass Change Prediction Model of Concrete Subjected to Sulfate Attack

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Kwang-Myong Lee ◽  
Su-Ho Bae ◽  
Jae-Im Park ◽  
Soon-Oh Kwon
Keyword(s):  
Prediction Model ◽  
Magnesium Sulfate ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Experimental Results ◽  
Mineral Admixture ◽  
Mass Change ◽  
Mineral Admixtures ◽  
Change Prediction

The present study suggested a mass change prediction model for sulfate attack of concrete containing mineral admixtures through an immersion test in sulfate solutions. For this, 100% OPC as well as binary and ternary blended cement concrete specimens were manufactured by changing the types and amount of mineral admixture. The concrete specimens were immersed in fresh water, 10% sodium sulfate solution, and 10% magnesium sulfate solution, respectively, and mass change of the specimens was measured at 28, 56, 91, 182, and 365 days. The experimental results indicated that resistance of concrete containing mineral admixture against sodium sulfate attack was far greater than that of 100% OPC concrete. However, in terms of resistance against magnesium sulfate attack, concrete containing mineral admixture was lower than 100% OPC concrete due to the formation of magnesium silicate hydrate (M-S-H), the noncementitious material. Ultimately, based on the experimental results, a mass change prediction model was suggested and it was found that the prediction values using the model corresponded relatively well with the experimental results.

X-Ray Microtomography of an Astm C109 Mortar Exposed to Sulfate Attack

1994 ◽  
Vol 370 ◽  
Author(s):  
D.P. Bentz ◽  
Nicos. S. Martys ◽  
P. Stutzman ◽  
M. S. Levenson ◽  
E.J. Garboczi ◽  
...  
Keyword(s):  
Cement Paste ◽  
Sodium Sulfate ◽  
Three Dimensional ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Mortar Sample ◽  
Air Voids ◽  
X Ray ◽  
Dimensional Image

AbstractX-ray microtomography can be used to generate three-dimensional 5123 images of random materials at a resolution of a few micrometers per voxel. This technique has been used to obtain an image of an ASTM C109 mortar sample that had been exposed to a sodium sulfate solution. The three-dimensional image clearly shows sand grains, cement paste, air voids, cracks, and needle-like crystals growing in the air voids. Volume fractions of sand and cement paste determined from the image agree well with the known quantities. Implications for the study of microstructure and proposed uses of X-ray microtomography on cement-based composites are discussed.

Study on the Durability of Concrete with Mineral Admixtures to Sulfate Attack by Wet-Dry Cycle Method

2011 ◽  
Vol 295-297 ◽  
pp. 165-169
Author(s):  
Guan Guo Liu ◽  
Jing Ming ◽  
Xiong Wen Zhang ◽  
Ai Bin Ma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sulfate Attack ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Change Environment ◽  
Physical Mechanisms ◽  
Chemical Attack ◽  
Tidal Area

Sulfate attack is one of several chemical and physical mechanisms of concrete deterioration. In actual situation, concrete structures always suffer from the coupled effects of multifactor such as wet-dry cycle and sulfate attack when exposed to tidal area or groundwater level change environment. Partial replacement of cement with mineral admixture is one of the efficient methods for improving concrete resistance against sulfate attack. In this regard, the resistance of concrete with fly ash and slag to sulfate attack was investigated by wet-dry cycle method. The degree of sulfate attack on specimens after different cycles was observed using scanning electron microscopy. The results of compressive strength and percentage of compressive strength evolution factor at various cycling times show an increase in the sulfate resistance of concrete with 60% of fly ash and slag than that only with 40% fly ash. The microstructural study indicates that the primary cause of deterioration of concrete under wet-dry cycle condition is swelling of the sulfate crystal rather chemical 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.

Sulfate Crystallization Attack on Cement-Based Materials

2008 ◽  
Vol 400-402 ◽  
pp. 89-99
Author(s):  
You Jun Xie ◽  
Kun Lin Ma ◽  
Guang Cheng Long
Keyword(s):  
Salt Solution ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Mineral Admixture ◽  
Experimental Investigations ◽  
Capillary Effect ◽  
Chemical Corrosion ◽  
Factors Affecting ◽  
Cement Based Materials ◽  
Close Relationship

The physical crystallization action of sulfate in cement based material, which often occurs by dry-wet cycle, capillary rising and evaporating action, can damage seriously cement-based materials as compared to chemical corrosion by sulfate. The deterioration mechanism of cement-based materials by sulfate crystallization attack, experimental investigations of the process of sodium sulfate crystallization and the factors affecting the process, and the invading track of salt solution by capillary effect are presented in this paper. Results show that the crystal type and crystallization velocity of sodium sulfate is influenced greatly by relative humidity and ambient temperature. There is a close relationship between invading depth and the porosity of concrete. Addition of mineral admixture to concrete can significantly reduce the invading depth of sodium sulfate solution and thereby enhance the resistance of concrete to sulfate crystallization attack.The profile of invading track of salt solution by capillary effect is similar to the shape of concave parabola.

Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years

2020 ◽  
Vol 70 (337) ◽  
pp. 212
Author(s):  
L. R. Santillán ◽  
F. Locati ◽  
Y. A. Villagrán-Zaccardi ◽  
C. J. Zega
Keyword(s):  
Sodium Sulfate ◽  
Fluorescent Microscopy ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Sodium Sulfate Solution ◽  
Microscopy Image

The effect of recycled concrete aggregate (RCA) on concrete performance against external sulfate attack (ESA) is not yet fully known. In this paper, recycled aggregate concretes (RAC) with 0, 50, 75 and 100% of RCA contents were evaluated after 10 years of exposure immersed in 50g/l sodium sulfate solution. Sulfate ingress profiles were obtained by wet chemical analyses and FRX. Also, the mineralogy of the ingress profile was evaluated by thermogravimetric analyses. Finally, microcracking development in samples was evaluated by optical fluorescent microscopy image analysis. Although RAC showed a slight increase in sulfate ingress, due to its higher porosity (about 30% higher SO3 content near the surface for 50% or higher replacement ratio than control concrete), a dense new matrix still allows a good performance of RAC to external sulfate attack with even 100% RCA content.

Rapid Quantitative Identification of Thaumasite

2013 ◽  
Vol 743-744 ◽  
pp. 186-192 ◽  
Author(s):  
Chang Cheng Li ◽  
Yan Yao ◽  
Ling Wang
Keyword(s):  
Magnesium Sulfate ◽  
Rietveld Refinement ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Identification Method ◽  
Quantitative Identification ◽  
Ir Analysis

To establish a quantitative identification method of thaumasite, internal doping method was used to accelerate thaumasite form of sulfate attack (TSA). A cement-limestone powder paste doped 10% of magnesium sulfate was immersed in water at (5±2) °C, while the blank was in 10% magnesium sulfate solution (by weight). Paste corrosion products were analyzed by infrared spectrum (IR), thermal analysis, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD)/Rietveld refinement methods. The results show that the thaumasite formation was successfully accelerated by internal doping method. A lot of thaumasite formed after 6-15 months low temperature sulfate attack with gray mud-like material. IR analysis is able to be used to analysis thaumasite qualitatively, and Rietveld refinement was suitable to quantitative analysis of thaumasite. A rapid quantitative identification method of thaumasite including visual inspection, IR spectrum and XRD/Rietveld refinement was also established which will improve the accuracy and rapidness of TSAs research.

Resistance to magnesium sulfate and sodium sulfate attack of mortars containing wheat straw ash

2000 ◽  
Vol 30 (8) ◽  
pp. 1189-1197 ◽  
Author(s):  
Hasan Biricik ◽  
Fevziye Aköz ◽  
Fikret Türker ◽  
Ilhan Berktay
Keyword(s):  
Magnesium Sulfate ◽  
Wheat Straw ◽  
Sodium Sulfate ◽  
Sulfate Attack ◽  
Straw Ash

Preparation and Performance of Sulfate Resistance Cement-Based Material

2008 ◽  
Vol 400-402 ◽  
pp. 195-201
Author(s):  
Feng Chen Zhang ◽  
Bao Guo Ma ◽  
Geng Yin ◽  
Yuan Yuan Wu ◽  
Yan Chao Zhu
Keyword(s):  
Magnesium Sulfate ◽  
Energy Dispersive Spectrometer ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Surface Erosion ◽  
Initial Surface ◽  
Control Specimen ◽  
X Ray ◽  
Sulfate Resistance ◽  
Magnesium Sulfate Solution

To discuss prevention of sulfate attack, especially thaumasite form of sulfate attack (TSA), sulfate resistance cement based material (SRM) were designed and prepared, and properties of which were investigated systematically. Micro-analytical techniques were introduced to identify erosion substances especially thaumasite, namely Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with X-ray energy dispersive spectrometer(EDS). Results show that SRM have better sulfate resistance, as well as TSA resistance, when exposed to aggressive environment with 33800 ppm mass concentration of SO42- in magnesium sulfate solution at 5°C±2°C. When immersed in magnesium sulfate solution for 40 weeks, compressive strength and tensile strength of SRM are still higher than their initial, and those of control specimen are lower by 33.7%, 36.5% compared to its initial. Surface erosion substances of SRM named S1 are ettringite and gypsum, while those of control specimen are ettringite, gypsum, thaumasite and brucite.

scholarly journals A comparable study on the deterioration of concrete under sodium sulfate and magnesium sulfate attack

2021 ◽  
Vol 787 (1) ◽  
pp. 012037
Author(s):  
Jiang Wu ◽  
Wen Zhu ◽  
Jiangxiong Wei ◽  
Mengxiong Tang ◽  
Shuo Zhang ◽  
...  
Keyword(s):  
Magnesium Sulfate ◽  
Sodium Sulfate ◽  
Sulfate Attack
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