The Experts below are selected from a list of 231096 Experts worldwide ranked by ideXlab platform
Gye-chun Cho - One of the best experts on this subject based on the ideXlab platform.
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Shear Strength Behavior and parameters of microbial gellan gum-treated soils: from sand to clay
Acta Geotechnica, 2018Co-Authors: Ilhan Chang, Gye-chun ChoAbstract:Microbial biopolymers have recently been introduced as a new material for soil treatment and improvement. Biopolymers provide significant Strengthening to soil, even in small quantities (i.e., at 1/10th or less of the required amount of conventional binders, such as cement). In particular, thermo-gelating biopolymers, including agar gum, gellan gum, and xanthan gum, are known to Strengthen soils noticeably, even under water-saturated conditions. However, an explicitly detailed examination of the microscopic interactions and Strengthening characteristics between gellan gum and soil particles has not yet been performed. In this study, a series of laboratory experiments were performed to evaluate the effect of soil–gellan gum interactions on the Strengthening Behavior of gellan gum-treated soil mixtures (from sand to clay). The experimental results showed that the Strengths of sand–clay mixtures were effectively increased by gellan gum treatment over those of pure sand or clay. The Strengthening Behavior is attributed to the conglomeration of fine particles as well as to the interconnection of fine and coarse particles, by gellan gum. Gellan gum treatment significantly improved not only inter-particle cohesion but also the friction angle of clay-containing soils.
Shuai Cao - One of the best experts on this subject based on the ideXlab platform.
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ct scanning of internal crack mechanism and Strength Behavior of cement fiber tailings matrix composites
Cement & Concrete Composites, 2021Co-Authors: Erol Yilmaz, Shuai Cao, Weidong Song, Gaili Xue, Zhenyu Yin, Lijuan SunAbstract:Abstract This paper deals the relationship between compressive Strength and internal crack formation (e.g., crack width and volume) of cement-fiber-tailings matrix composites (CFTMC) using an industrial computed tomography system and scanning electron microscopy. Two types of fibers (polypropylene PP and polyacrylonitrile PAN) were used to manufacture CFTMC with a constant cement-to-tailings ratio, solid content and curing time of 1:6, 75 wt% and 14 days, respectively. The results showed that Strength gaining of CFTMC increased remarkably with fiber additions which effectively improve its toughness. When compared to samples without fibers, the compressive Strength of CFTMC was the highest because of the reduced interconnection between pores and high particle packing density. The internal structure analysis showed that the maximum crack widths of CFTMC increased when the fiber content increased from 0.3 to 0.6 wt%, regardless of fiber type, growing the crack volumes of samples. The failure pattern of all CFTMC samples was mainly tensile, shear and mixed failure (tensile/shear), and a high Strength value accompanies with a big volume of crack. At last, the findings of this study may offer a key reference for fiber-reinforced backfills, which can lift their Strength, stability and integrity Behavior under extreme conditions, such as rock burst, squeezing ground, blast or seismic event.
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loading rate effect on uniaxial compressive Strength Behavior and acoustic emission properties of cemented tailings backfill
Construction and Building Materials, 2019Co-Authors: Shuai Cao, Erol Yilmaz, Weidong Song, Elif Yilmaz, Gaili XueAbstract:Abstract To understand the quality and Behavior of cemented tailings backfill (CTB) subjected to dynamic loads, the influence of change in the rate of loading should be accurately determined for an efficient mine fill design. In this study, the compressive Strength Behavior and acoustic emission (AE) characteristics of 180-day cured CTB samples are investigated by using four different loading rates: 50 N/s, 100 N/s, 150 N/s, and 200 N/s. Samples were prepared with the classified tailings and cementitious material of a gold mine as raw materials and subjected to the uniaxial compressive test using mechanical testing machine (GAW-2000) and AE equipment (PCI-2). Experimental results indicate that: (1) the loading rate has a Strengthening effect on long-term Strength Behavior of CTB samples, and there is a power function between peak compressive Strength of CTB samples and loading rate. The stress state of the backfill mass is “stepped” growth before the peak compressive Strength, and the whole process displays a multi-cycle of “surge-steady-surge-steady”; (2) during the loading process, the ring count distribution has a regular peak-spacing effect, and the cumulative ring counts are also “stepped” and inclined to be stable. (3) With the increase of loading rate, the failure mode of CTB is a transition from tensile and shear mixing (mainly shear stress) to X-type shear failure. Ultimately, the essential findings of this experimental work will provide a scientific reference for studying the dynamic characteristics of CTB samples.
Gaili Xue - One of the best experts on this subject based on the ideXlab platform.
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ct scanning of internal crack mechanism and Strength Behavior of cement fiber tailings matrix composites
Cement & Concrete Composites, 2021Co-Authors: Erol Yilmaz, Shuai Cao, Weidong Song, Gaili Xue, Zhenyu Yin, Lijuan SunAbstract:Abstract This paper deals the relationship between compressive Strength and internal crack formation (e.g., crack width and volume) of cement-fiber-tailings matrix composites (CFTMC) using an industrial computed tomography system and scanning electron microscopy. Two types of fibers (polypropylene PP and polyacrylonitrile PAN) were used to manufacture CFTMC with a constant cement-to-tailings ratio, solid content and curing time of 1:6, 75 wt% and 14 days, respectively. The results showed that Strength gaining of CFTMC increased remarkably with fiber additions which effectively improve its toughness. When compared to samples without fibers, the compressive Strength of CFTMC was the highest because of the reduced interconnection between pores and high particle packing density. The internal structure analysis showed that the maximum crack widths of CFTMC increased when the fiber content increased from 0.3 to 0.6 wt%, regardless of fiber type, growing the crack volumes of samples. The failure pattern of all CFTMC samples was mainly tensile, shear and mixed failure (tensile/shear), and a high Strength value accompanies with a big volume of crack. At last, the findings of this study may offer a key reference for fiber-reinforced backfills, which can lift their Strength, stability and integrity Behavior under extreme conditions, such as rock burst, squeezing ground, blast or seismic event.
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loading rate effect on uniaxial compressive Strength Behavior and acoustic emission properties of cemented tailings backfill
Construction and Building Materials, 2019Co-Authors: Shuai Cao, Erol Yilmaz, Weidong Song, Elif Yilmaz, Gaili XueAbstract:Abstract To understand the quality and Behavior of cemented tailings backfill (CTB) subjected to dynamic loads, the influence of change in the rate of loading should be accurately determined for an efficient mine fill design. In this study, the compressive Strength Behavior and acoustic emission (AE) characteristics of 180-day cured CTB samples are investigated by using four different loading rates: 50 N/s, 100 N/s, 150 N/s, and 200 N/s. Samples were prepared with the classified tailings and cementitious material of a gold mine as raw materials and subjected to the uniaxial compressive test using mechanical testing machine (GAW-2000) and AE equipment (PCI-2). Experimental results indicate that: (1) the loading rate has a Strengthening effect on long-term Strength Behavior of CTB samples, and there is a power function between peak compressive Strength of CTB samples and loading rate. The stress state of the backfill mass is “stepped” growth before the peak compressive Strength, and the whole process displays a multi-cycle of “surge-steady-surge-steady”; (2) during the loading process, the ring count distribution has a regular peak-spacing effect, and the cumulative ring counts are also “stepped” and inclined to be stable. (3) With the increase of loading rate, the failure mode of CTB is a transition from tensile and shear mixing (mainly shear stress) to X-type shear failure. Ultimately, the essential findings of this experimental work will provide a scientific reference for studying the dynamic characteristics of CTB samples.
Ilhan Chang - One of the best experts on this subject based on the ideXlab platform.
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Shear Strength Behavior and parameters of microbial gellan gum-treated soils: from sand to clay
Acta Geotechnica, 2018Co-Authors: Ilhan Chang, Gye-chun ChoAbstract:Microbial biopolymers have recently been introduced as a new material for soil treatment and improvement. Biopolymers provide significant Strengthening to soil, even in small quantities (i.e., at 1/10th or less of the required amount of conventional binders, such as cement). In particular, thermo-gelating biopolymers, including agar gum, gellan gum, and xanthan gum, are known to Strengthen soils noticeably, even under water-saturated conditions. However, an explicitly detailed examination of the microscopic interactions and Strengthening characteristics between gellan gum and soil particles has not yet been performed. In this study, a series of laboratory experiments were performed to evaluate the effect of soil–gellan gum interactions on the Strengthening Behavior of gellan gum-treated soil mixtures (from sand to clay). The experimental results showed that the Strengths of sand–clay mixtures were effectively increased by gellan gum treatment over those of pure sand or clay. The Strengthening Behavior is attributed to the conglomeration of fine particles as well as to the interconnection of fine and coarse particles, by gellan gum. Gellan gum treatment significantly improved not only inter-particle cohesion but also the friction angle of clay-containing soils.
Erol Yilmaz - One of the best experts on this subject based on the ideXlab platform.
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ct scanning of internal crack mechanism and Strength Behavior of cement fiber tailings matrix composites
Cement & Concrete Composites, 2021Co-Authors: Erol Yilmaz, Shuai Cao, Weidong Song, Gaili Xue, Zhenyu Yin, Lijuan SunAbstract:Abstract This paper deals the relationship between compressive Strength and internal crack formation (e.g., crack width and volume) of cement-fiber-tailings matrix composites (CFTMC) using an industrial computed tomography system and scanning electron microscopy. Two types of fibers (polypropylene PP and polyacrylonitrile PAN) were used to manufacture CFTMC with a constant cement-to-tailings ratio, solid content and curing time of 1:6, 75 wt% and 14 days, respectively. The results showed that Strength gaining of CFTMC increased remarkably with fiber additions which effectively improve its toughness. When compared to samples without fibers, the compressive Strength of CFTMC was the highest because of the reduced interconnection between pores and high particle packing density. The internal structure analysis showed that the maximum crack widths of CFTMC increased when the fiber content increased from 0.3 to 0.6 wt%, regardless of fiber type, growing the crack volumes of samples. The failure pattern of all CFTMC samples was mainly tensile, shear and mixed failure (tensile/shear), and a high Strength value accompanies with a big volume of crack. At last, the findings of this study may offer a key reference for fiber-reinforced backfills, which can lift their Strength, stability and integrity Behavior under extreme conditions, such as rock burst, squeezing ground, blast or seismic event.
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loading rate effect on uniaxial compressive Strength Behavior and acoustic emission properties of cemented tailings backfill
Construction and Building Materials, 2019Co-Authors: Shuai Cao, Erol Yilmaz, Weidong Song, Elif Yilmaz, Gaili XueAbstract:Abstract To understand the quality and Behavior of cemented tailings backfill (CTB) subjected to dynamic loads, the influence of change in the rate of loading should be accurately determined for an efficient mine fill design. In this study, the compressive Strength Behavior and acoustic emission (AE) characteristics of 180-day cured CTB samples are investigated by using four different loading rates: 50 N/s, 100 N/s, 150 N/s, and 200 N/s. Samples were prepared with the classified tailings and cementitious material of a gold mine as raw materials and subjected to the uniaxial compressive test using mechanical testing machine (GAW-2000) and AE equipment (PCI-2). Experimental results indicate that: (1) the loading rate has a Strengthening effect on long-term Strength Behavior of CTB samples, and there is a power function between peak compressive Strength of CTB samples and loading rate. The stress state of the backfill mass is “stepped” growth before the peak compressive Strength, and the whole process displays a multi-cycle of “surge-steady-surge-steady”; (2) during the loading process, the ring count distribution has a regular peak-spacing effect, and the cumulative ring counts are also “stepped” and inclined to be stable. (3) With the increase of loading rate, the failure mode of CTB is a transition from tensile and shear mixing (mainly shear stress) to X-type shear failure. Ultimately, the essential findings of this experimental work will provide a scientific reference for studying the dynamic characteristics of CTB samples.
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effect of superplasticizer type and dosage on fluidity and Strength Behavior of cemented tailings backfill with different solid contents
Construction and Building Materials, 2018Co-Authors: Junwei Li, Haiqiang Jiang, Erol Yilmaz, Lei YangAbstract:Abstract This paper presents the coupled effect of solid content and superplasticizer type and dosage on the fluidity and Strength properties of cemented tailings backfills (CTB). A total of three different superplasticizers (namely, naphthalene, ether-based and ester-based polycarboxylate) were used at a ratio varying from 0% to 0.5% by mass of CTB. The CTB mixes were proportioned with a solid content of 65%, 66%, 68% and 70%. The unconfined compressive Strength tests were performed on CTB samples after 3, 7 and 28 days of curing period. The obtained results show that the effect of superplasticizer on CTB performance depends on type and dosage of the superplasticizer used as well as solid content. The naphthalene-based polycarboxylate admixtures demonstrate the best improvement on fluidity Behavior of fresh CTB mixture. For a given superplasticizer type, increases in the dosage of superplasticizer and decreases in the solid content lead to better workability of CTB samples. When increasing solid content, fresh CTB with high superplasticizer dosage performs a relatively low rate of decrease in the workability. A relatively high solid content and superplasticizer dosage have greatly contributed to improved mechanical Strengths, especially at 28-day curing age, mainly due to a major reduction in water-to-cement ratio and porosity.
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specimen size effect on Strength Behavior of cemented paste backfills subjected to different placement conditions
Engineering Geology, 2015Co-Authors: Erol Yilmaz, Tikou Belem, Mostafa BenzaazouaAbstract:Abstract This paper investigates the specimen size effect on the Strength properties of cemented paste backfill through unconfined compressive Strength tests. Paste backfill samples were cast in different size molds (D × H: 10 × 20 cm, 7.5 × 15 cm, and 5 × 10 cm) and subjected to the four placement conditions: capped–drained C–D; uncapped–drained U–D; capped–undrained C–U; and uncapped–undrained U–U. The unconsolidated samples were also compared with consolidated backfills. Results show that the highest Strengths were obtained from the C–D samples cast in the mold 5 × 10 cm, followed by the U–D, C–U and U–U samples. This could be explained by the removal of excess water within paste backfill, the decreased number of micro-cracks in grains, and the wall effects. With the drainage of excess water, particles are pulled together under capillary forces, resulting in an increase of stiffness, accelerating binder hydration and thus, producing higher Strengths. Further, specimen size effect on water content, void ratio, mercury intrusion porosity, and degree of saturation of cemented paste backfill were presented. Some scale effect relationships were finally expressed and discussed.
