Image analysis of sulfate attack on hardened cement paste

Sezer, Gözde İnan; Ramyar, Kambiz; Karasu, Bekir; Göktepe, A. Burak; Sezer, Alper

doi:10.1016/j.matdes.2006.12.006

Cited by 74 publications

(8 citation statements)

References 17 publications

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“…To improve concrete resistance to sulphate attack, many researchers have been developing high-performance concrete (HPC), which contains materials such as fly ash, silica fume, volcanic ash, natural pozzolan, fibers, and other materials, either separately or in various combinations (Park et al, 1999;Mbessa and Péra, 2001;Shannag and Shaia, 2003;Dawood and Ramli, 2012). The use of fly ash or silica fume has been reported as a highly effective treatment for reducing sulphate-induced damage or enhancing the sulphate resistance of cements (Torii et al, 1995;Lee et al, 2005;Sezer et al, 2008;Bonakdar and Mobasher, 2010). Reducing the concrete w/b ratio or adopting a suitable type of cement can also improve concrete resistance to sulphate attack (Monteiro and Kurtis, 2003;Kockal and Turker, 2007;Chen and Jiang, 2009).…”

Section: Introductionmentioning

confidence: 99%

Sulphate attack resistance of high-performance concrete under compressive loading

Zhao

Cui

et al. 2013

J. Zhejiang Univ. Sci. A

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Abstract:In this paper, an experimental study on the sulphate attack resistance of high-performance concrete (HPC) with two different water-to-binder ratios (w/b) under compressive loading is presented. The sulphate concentration, compressive strength, and the mass change in the HPC specimens were determined for immersion in a Na 2 SO 4 solution over different durations under external compressive loading by self-regulating loading equipment. The effects of the compressive stress, the w/b ratio, and the Na 2 SO 4 solution concentration on the HPC sulphate attack resistance under compressive loading were analysed. The results showed that the HPC sulphate attack resistance under compressive loading was closely related to the stress level, the w/b ratio, and the Na 2 SO 4 solution concentration. Applying a 0.3 stress ratio for the compressive loading or reducing the w/b ratio clearly improved the HPC sulphate attack resistance, whereas applying a 0.6 stress ratio for the compressive loading or exposing the HPC to a more concentrated Na 2 SO 4 solution accelerated the sulphate attack and HPC deterioration.

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Section: Introductionmentioning

confidence: 99%

Sulphate attack resistance of high-performance concrete under compressive loading

Zhao

Cui

et al. 2013

J. Zhejiang Univ. Sci. A

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“…(2))). (2) 1 nR = β 2 1 nA + C , where β /2 represents the slope of the linear fit of LnR to LnA, and C is a constant. The fractal dimension of pore fracture morphology in SEM images of mud shale reservoirs is D = 3 − β / 2 according to Pan et al In addition, the roundness ( r ) is also a shape factor reflecting the pore roughness [28, 29], and the expression (3) is (3) r = 4 A / π R 2 …”

Section: Resultsmentioning

confidence: 99%

Micropore Characteristics and Gas-Bearing Characteristics of Marine-Continental Transitional Shale Reservoirs in the East Margin of Ordos Basin

Meng

et al. 2021

Adsorption Science & Technology

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In order to deeply study the exploration potential of Carboniferous-Permian marine-continental transitional shale reservoirs in the Ordos Basin, the shale samples from well Y1 in the central-southern part of the Hedong Coalfield were used as the research object. The organic geochemical test, scanning electron microscope, X-ray diffraction, and high pressure mercury injection and low-temperature nitrogen adsorption experiments have studied the microscopic characteristics and gas content characteristics of shale reservoirs. The results show that the organic matter type of the sample is type III; the TOC content ranges from 0.28% to 16.87%, with an average of 2.15%; R o is from 2.45% to 3.36%, with an average value of 2.86%; the shale pores in the study area are well developed, containing more organic pores and intergranular pores of clay minerals. Based on the two-dimensional SEM image fractal theory to study different types of pores, the fractal dimension of shale pore fracture morphology is between 2.34 and 2.50, and the heterogeneity is moderate. The high-pressure mercury intrusion experiment characterizes the pore size distribution of shale macropores and transition pores. The pore diameters are mostly nm-scale. Transition pores are the main pores of the shale in the study area. Based on the characteristics of the pore structure, the adsorption capacity and gas content of CH4 in shale reservoir were analyzed by methane isothermal adsorption and gas content experiments. The results showed that the pore volume and specific surface area were positively correlated with clay mineral content, TOC, and RO, but negatively correlated with the quartz content. In clay minerals and brittle minerals, pore volume and specific surface area are positively correlated with illite content and negatively correlated with the quartz and kaolinite content. The measured total gas content and desorbed gas content are significantly positively correlated with TOC, but are weakly positively correlated with the quartz and illite content. This study finely characterizes the physical properties, micropore characteristics, gas-bearing characteristics, and influencing factors of shale reservoirs, which has certain theoretical guiding significance for the research and development of coal-measure shale in the Ordos Basin.

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“…For example, the circular surface is smoother than the triangle, and the shape factor value of the circle is larger . The shape factor is usedto describe the morphological characteristics of pores in two-dimensional images, and it can be used to analyze the two-dimensional pore connectivity of rocks (eq ) , : .25ex2ex ff = 4 π S C 2 …”

Section: Experimental and Data Processing Methodsmentioning

confidence: 99%

Controlling Effect of Shale Pore Connectivity on the Adsorption State of Shale Gas: A Case Study of Continental Shale of Jurassic Ziliujing Formation, Sichuan Basin

Bai,

Duan,

Gao

et al. 2023

Energy Fuels

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The pore connectivity of shale directly affects the migration and distribution of oil and gas within shale reservoirs and controls the adsorption state of shale gas by determining the accessible pore spaces for methane molecules. However, previous studies mostly focused on the surficial properties, pore size, and specific surface area, ignoring the significant impact of pore connectivity on the adsorption state of shale gas. Accordingly, taking the continental shale of the Jurassic Ziliujing Formation from the northeastern Sichuan Basin as the research object, this study mainly investigates the effects of shale pore connectivity on the adsorption state of shale gas by conducting methane adsorption and field emission scanning electron microscopy experiments together with image processing software. The results show that the methane adsorption capacity per unit specific surface area of type III kerogen is higher than that of type II 2 kerogen, indicating type III kerogen has a stronger affinity to methane. However, the total methane adsorption capacity of type II 2 kerogen in Ziliujing Formation shale samples is about four times that of type III kerogen, which is due to the much higher specific surface area, providing more methane adsorption sites. The development of OM and clay minerals in the shale of the Ziliujing Formation has a certain orientation and promotes the pore connectivity of the shale. Furthermore, a better pore connectivity of shale samples, which is usually accompanied by more developed microfractures of OM and clay minerals, higher roughness of pore surface, and stronger randomness of pore arrangement, results in a stronger methane adsorption capacity. Based on the close relationship between pore connectivity and methane adsorption capacity, a new pore connectivity index is proposed, considering the difference between the actual and the theoretical methane adsorption capacity of shale samples. Finally, a shale methane adsorption model is established based on pore connectivity.

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Image analysis of sulfate attack on hardened cement paste

Cited by 74 publications

References 17 publications

Sulphate attack resistance of high-performance concrete under compressive loading

Sulphate attack resistance of high-performance concrete under compressive loading

Micropore Characteristics and Gas-Bearing Characteristics of Marine-Continental Transitional Shale Reservoirs in the East Margin of Ordos Basin

Controlling Effect of Shale Pore Connectivity on the Adsorption State of Shale Gas: A Case Study of Continental Shale of Jurassic Ziliujing Formation, Sichuan Basin

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