Irem Zeynep Yildirim - Academia.edu (original) (raw)

Papers by Irem Zeynep Yildirim

Journal of Geotechnical and Geoenvironmental Engineering, 2009

... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 ... more ... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 mm/hr, the next load increment was applied only after the difference in settlement rate between the ... “Fromstrain measurements to ... “Stiffness degradation and shear strength of silty sands.” Can ...

Advances in Civil Engineering, 2011

Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an... more Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF) steelmaking, electric-arc-furnace (EAF) steelmaking, and ladle-furnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace-ladle [EAF(L)] slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM) studies. The XRD patterns of both BOF and EAF(L) slag samples were very complex, with several overlapping peaks resulting from the many minerals present in these samples. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L) slag samples. SEM micrographs showed that the majority of the sand-size steel slag particles had subangular to angular shapes. Very rough surface textures with distinct crystal structures were observed...

International Journal of Pavement Engineering

This study investigates the viability of using electric-arc-furnace steel slag (EAF SS)-blast fur... more This study investigates the viability of using electric-arc-furnace steel slag (EAF SS)-blast furnace slag (BFS) and EAF SS-Class C fly ash (FA) mixtures as a replacement for lime or cement in subg...

Construction and Building Materials

Abstract Despite of significant efforts in the last decades towards utilization of steel slag in ... more Abstract Despite of significant efforts in the last decades towards utilization of steel slag in the construction industry, steel slag stockpiling and landfilling operations do not seem to be declining in steel-producing countries. Use of steel slag as a construction material requires understanding of its engineering properties and development of a methodology to address its swelling potential. This paper focuses on the results of a series of laboratory tests (grain-size analysis, X-ray diffraction, specific gravity, compaction, maximum and minimum dry unit weight, direct shear, and long-term swelling tests) performed on samples of electric-arc-furnace ladle (EAF(L)) steel slag to assess its potential to be used as a geo-material. Direct shear test results indicated that the EAF(L) steel slag exhibits comparable frictional properties to angular crushed sand. Based on the leachate concentration levels from TCLP analyses, the EAF(L) steel slag tested was classified as Type III Solid Waste. The long-term, one-dimensional (1D) swelling test results showed continued volumetric expansion even after more than 16 months of monitoring. Replacing 5–10% by weight of EAF (L) steel slag with Class C fly ash reduced the 1D swelling to negligible levels.

Geo-Chicago 2016, 2016

Use of industrial by-products in geotechnical engineering projects, such as in the construction o... more Use of industrial by-products in geotechnical engineering projects, such as in the construction of highway embankments, is advantageous because large volumes of these materials can be utilized. Basic oxygen furnace (BOF) steel slag is one of these industrial by-products. This paper provides a brief background on the characteristics of BOF steel slag and presents the results of a series of laboratory tests (grain-size analysis, maximum and minimum dry density, compaction, large-scale direct shear tests (LDS) and isotropically consolidated-drained triaxial compression (CID TX) performed on fresh and aged BOF steel slag generated from an Indiana steel plant. BOF steel slag samples from three different batches of production were tested, which allowed an evaluation of both aging processes and the effect of changes in gradation on the mechanical properties. The BOF steel slag tested in this study contained sand-size particles with varying percentages of gravel- and silt-size fractions. The moisture-density relationships for BOF steel slag were irregular with two peaks. Based on the LDS and CID TX test results, the BOF steel slag exhibited superior strength and stiffness characteristics than conventional geo-materials. The mechanical properties of fresh and aged BOF steel slag are discussed in the context of its use in geotechnical applications.

Steel slag is a by-product of the steelmaking and steel refining processes. In 2006, 10-15 millio... more Steel slag is a by-product of the steelmaking and steel refining processes. In 2006, 10-15 million metric tons of steel slag were generated in the U.S. Out of the total steel slag produced in the U.S. every year, about 50-70% is used as aggregate for road and pavement construction and approximately 15-40% is stockpiled in steel plants and eventually landfilled

Journal of Materials in Civil Engineering, 2013

AbstractThe steelmaking industry in the United States generates 9–16 million metric tons of steel... more AbstractThe steelmaking industry in the United States generates 9–16 million metric tons of steel slag every year. The excess steel slag (∼15 to 40%) that is not reutilized is stockpiled in steel plants and eventually landfilled at slag disposal sites. Use of steel slag in civil engineering applications can help alleviate the steel slag disposal problem and help preserve natural resources. Understanding the in-service performance of steel slag is essential for its proper use as a geomaterial by the construction industry. In this paper, the results of a series of tests (grain-size analysis, X-ray diffraction, specific gravity, compaction, maximum and minimum dry unit weight, direct shear, consolidated-drained triaxial compression, and long-term swelling tests) performed on samples of both fresh and aged basic oxygen furnace (BOF) steel slag from a steel plant in Indiana are presented and analyzed. The test results indicated that both fresh and aged BOF steel slag exhibit superior strength and stiffness cha...

IFCEE 2015, 2015

Steel slag is a by-product of the steel industry. Understanding of the chemical, mineralogical an... more Steel slag is a by-product of the steel industry. Understanding of the chemical, mineralogical and morphological properties of steel slag are necessary for its use in sustainable practices. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF) steelmaking, electric-arc-furnace (EAF) steelmaking, and ladle furnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace- ladle (EAF(L)) slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM) studies. The XRD patterns of both BOF and EAF(L) slag samples were very complex, with several overlapping peaks resulting from the variety of minerals present in these materials. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L) slag samples. SEM micrographs showed that the sand-size steel slag particles had subangular to angular shapes and very rough surface textures. The characteristics of the steel slag samples considered in this study are discussed in the context of a detailed review of steel slag particle properties for its potential use in geotechnical applications.

Epilepsy & Behavior, 2015

Despite the explanations of many lateralization findings, body turning in focal epilepsy has been... more Despite the explanations of many lateralization findings, body turning in focal epilepsy has been rarely investigated. One of the aims of this study was to evaluate the role of ictal body turning in the lateralization of focal epilepsies. The records of 263 patients with focal epilepsy (temporal lobe epilepsy (TLE), n=178; extratemporal lobe epilepsy (ETLE), n=85) who underwent prolonged video-EEG monitoring during presurgical epilepsy evaluation were reviewed. Preoperative findings (TLE, n=16; ETLE, n=6) and postoperative outcomes (TLE, n=7) of patients with focal epilepsy with ictal body turning were assessed. For the evaluation of ictal body turning, two definitions were proposed. Nonversive body turning (NVBT) was used to denote at least a 90° nonforced (without tonic or clonic component) rotation of the upper (shoulder) and lower (hip) parts of the body around the body axis for a minimum of 3s. Versive body turning (VBT) was used to denote at least a 90° forced (with tonic or clonic component) rotation of the upper (shoulder) and lower (hip) parts of the body around the body axis for a minimum of 3s. Nonversive body turning was observed in 6% (n=11) of patients with TLE and 2% (n=2) of patients with ETLE. For VBT, these ratios were 5% (n=8) and 7% (n=6) for patients with TLE and ETLE, respectively. Nonversive body turning was frequently oriented to the same side as the epileptogenic zone (EZ) in TLE and ETLE seizures (76% and 80%, respectively). If the amount of NVBT was greater than 180°, then it was 80% to the same side in TLE seizures. Versive body turning was observed in 86% of the TLE seizures, and 55% of the ETLE seizures were found to be contralateral to the EZ. When present with head turning, NVBT ipsilateral to the EZ and VBT contralateral to the EZ were more valuable for lateralization. In TLE seizures, a significant correlation was found between the head turning and body turning onsets and durations. Our study demonstrated that ictal body turning is a rarely observed but reliable lateralization finding in TLE and ETLE seizures, which also probably has the same pathophysiological mechanism as head turning in TLE seizures.

Fly ash and bottom ash are coal combustion by-products (CCBPs) that are generated in large quanti... more Fly ash and bottom ash are coal combustion by-products (CCBPs) that are generated in large quantities throughout the world. It is often economical to dispose ash as mixtures rather than separately; that notwithstanding, only a few studies have been performed to investigate the behavior of fly and bottom ash mixtures, particularly those with high contents of fly ash. Also, there

Journal of Geotechnical and Geoenvironmental Engineering, 2009

... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 ... more ... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 mm/hr, the next load increment was applied only after the difference in settlement rate between the ... “Fromstrain measurements to ... “Stiffness degradation and shear strength of silty sands.” Can ...

Steel slag is a by-product of steelmaking and refining processes. In 2006, 10-15 million metric t... more Steel slag is a by-product of steelmaking and refining processes. In 2006, 10-15 million metric ton of steel slag was generated in the U.S. Out of the total steel slag produced in the U.S. every year, about 50-70% is used as aggregate for road and pavement construction and approximately 15-40% is stockpiled in steel plants and eventually landfilled at slag disposal sites. Since current levels of steel slag stockpiling and landfilling are not sustainable, alternative geotechnical engineering applications for steel slag are being explored to alleviate the slag disposal problem and to help save dwindling natural resources. The main objectives of this research were to determine the geotechnical engineering properties of two types of steel slag generated from different steelmaking operations and to assess their potential use in subgrade stabilization and embankment construction. Samples of fresh and aged basic-oxygen-furnace (BOF) slag and of fresh electric-arc-furnace-ladle (EAF(L)) slag were characterized through a series of laboratory tests (specific gravity, grain-size analysis, X-ray diffraction, compaction, maximum and minimum density, large-scale direct shear, consolidated drained triaxial and swelling tests). The effects of gradation on the engineering properties of both fresh and aged steel slag samples were also investigated. Various mixtures of steel slag [BOF and EAF(L)] and Class-C fly ash were also investigated. The mixtures were prepared by adding 5 and 10% Class-C fly ash (by weight) to aged BOF slag and 5, 10 and 20% Class-C fly ash (by weight) to fresh EAF(L) slag. Unconfined compression tests were performed after various curing times to evaluate the strength gain characteristics of the mixtures. Long-term swelling tests were performed for compacted mixtures of both fresh and aged BOF slag and 10% Class-C fly ash (by weight) and for compacted mixtures of fresh EAF(L) slag and 5, 10 and 20% Class-C fly ash (by weight). The effect of adding 10% ground rubber (by weight) to fresh and aged BOF slag on the long-term swelling behavior of the mixtures was also investigated. The optimum moisture content and maximum dry unit weight of BOF slag were in the ranges of 4-8% and 19.5-21.8 kN/m 3 , respectively. The critical-state friction angle of fresh and aged BOF slags was in the 45.3°-48.1° range according to large-scale direct shear test results. Based on isotropically consolidated drained triaxial test (CIDTX) results, the peak friction angles of aged BOF slag (with minus 9.5 mm gradation) samples prepared at 90% relative compaction were equal to 47.3°, 45.2° and 43.5° at effective confining stresses of 50, 110 and 200 kPa, respectively. The optimum moisture content and maximum dry unit weight of EAF(L) slag were in the ranges of 10-13% and 16.8-20.0 kN/m 3 , respectively. The critical-state friction angle of fresh EAF(L) slag was equal to approximately 40.6° according to large-scale direct shear tests results. Compacted mixtures of both Class-C fly ash and BOF slag and of Class-C fly ash and EAF(L) slag showed excellent strength gain properties with time. Results of the long-term swelling tests on steel slag and Class-C fly ash mixtures showed that the addition of 10% Class-C fly ash suppresses the swelling of both BOF and EAF(L) slag samples to negligible levels. .

Journal of Geotechnical and Geoenvironmental Engineering, 2009

... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 ... more ... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 mm/hr, the next load increment was applied only after the difference in settlement rate between the ... “Fromstrain measurements to ... “Stiffness degradation and shear strength of silty sands.” Can ...

Advances in Civil Engineering, 2011

Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an... more Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF) steelmaking, electric-arc-furnace (EAF) steelmaking, and ladle-furnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace-ladle [EAF(L)] slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM) studies. The XRD patterns of both BOF and EAF(L) slag samples were very complex, with several overlapping peaks resulting from the many minerals present in these samples. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L) slag samples. SEM micrographs showed that the majority of the sand-size steel slag particles had subangular to angular shapes. Very rough surface textures with distinct crystal structures were observed...

International Journal of Pavement Engineering

This study investigates the viability of using electric-arc-furnace steel slag (EAF SS)-blast fur... more This study investigates the viability of using electric-arc-furnace steel slag (EAF SS)-blast furnace slag (BFS) and EAF SS-Class C fly ash (FA) mixtures as a replacement for lime or cement in subg...

Construction and Building Materials

Abstract Despite of significant efforts in the last decades towards utilization of steel slag in ... more Abstract Despite of significant efforts in the last decades towards utilization of steel slag in the construction industry, steel slag stockpiling and landfilling operations do not seem to be declining in steel-producing countries. Use of steel slag as a construction material requires understanding of its engineering properties and development of a methodology to address its swelling potential. This paper focuses on the results of a series of laboratory tests (grain-size analysis, X-ray diffraction, specific gravity, compaction, maximum and minimum dry unit weight, direct shear, and long-term swelling tests) performed on samples of electric-arc-furnace ladle (EAF(L)) steel slag to assess its potential to be used as a geo-material. Direct shear test results indicated that the EAF(L) steel slag exhibits comparable frictional properties to angular crushed sand. Based on the leachate concentration levels from TCLP analyses, the EAF(L) steel slag tested was classified as Type III Solid Waste. The long-term, one-dimensional (1D) swelling test results showed continued volumetric expansion even after more than 16 months of monitoring. Replacing 5–10% by weight of EAF (L) steel slag with Class C fly ash reduced the 1D swelling to negligible levels.

Geo-Chicago 2016, 2016

Use of industrial by-products in geotechnical engineering projects, such as in the construction o... more Use of industrial by-products in geotechnical engineering projects, such as in the construction of highway embankments, is advantageous because large volumes of these materials can be utilized. Basic oxygen furnace (BOF) steel slag is one of these industrial by-products. This paper provides a brief background on the characteristics of BOF steel slag and presents the results of a series of laboratory tests (grain-size analysis, maximum and minimum dry density, compaction, large-scale direct shear tests (LDS) and isotropically consolidated-drained triaxial compression (CID TX) performed on fresh and aged BOF steel slag generated from an Indiana steel plant. BOF steel slag samples from three different batches of production were tested, which allowed an evaluation of both aging processes and the effect of changes in gradation on the mechanical properties. The BOF steel slag tested in this study contained sand-size particles with varying percentages of gravel- and silt-size fractions. The moisture-density relationships for BOF steel slag were irregular with two peaks. Based on the LDS and CID TX test results, the BOF steel slag exhibited superior strength and stiffness characteristics than conventional geo-materials. The mechanical properties of fresh and aged BOF steel slag are discussed in the context of its use in geotechnical applications.

Steel slag is a by-product of the steelmaking and steel refining processes. In 2006, 10-15 millio... more Steel slag is a by-product of the steelmaking and steel refining processes. In 2006, 10-15 million metric tons of steel slag were generated in the U.S. Out of the total steel slag produced in the U.S. every year, about 50-70% is used as aggregate for road and pavement construction and approximately 15-40% is stockpiled in steel plants and eventually landfilled

Journal of Materials in Civil Engineering, 2013

AbstractThe steelmaking industry in the United States generates 9–16 million metric tons of steel... more AbstractThe steelmaking industry in the United States generates 9–16 million metric tons of steel slag every year. The excess steel slag (∼15 to 40%) that is not reutilized is stockpiled in steel plants and eventually landfilled at slag disposal sites. Use of steel slag in civil engineering applications can help alleviate the steel slag disposal problem and help preserve natural resources. Understanding the in-service performance of steel slag is essential for its proper use as a geomaterial by the construction industry. In this paper, the results of a series of tests (grain-size analysis, X-ray diffraction, specific gravity, compaction, maximum and minimum dry unit weight, direct shear, consolidated-drained triaxial compression, and long-term swelling tests) performed on samples of both fresh and aged basic oxygen furnace (BOF) steel slag from a steel plant in Indiana are presented and analyzed. The test results indicated that both fresh and aged BOF steel slag exhibit superior strength and stiffness cha...

IFCEE 2015, 2015

Steel slag is a by-product of the steel industry. Understanding of the chemical, mineralogical an... more Steel slag is a by-product of the steel industry. Understanding of the chemical, mineralogical and morphological properties of steel slag are necessary for its use in sustainable practices. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF) steelmaking, electric-arc-furnace (EAF) steelmaking, and ladle furnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace- ladle (EAF(L)) slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM) studies. The XRD patterns of both BOF and EAF(L) slag samples were very complex, with several overlapping peaks resulting from the variety of minerals present in these materials. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L) slag samples. SEM micrographs showed that the sand-size steel slag particles had subangular to angular shapes and very rough surface textures. The characteristics of the steel slag samples considered in this study are discussed in the context of a detailed review of steel slag particle properties for its potential use in geotechnical applications.

Epilepsy & Behavior, 2015

Despite the explanations of many lateralization findings, body turning in focal epilepsy has been... more Despite the explanations of many lateralization findings, body turning in focal epilepsy has been rarely investigated. One of the aims of this study was to evaluate the role of ictal body turning in the lateralization of focal epilepsies. The records of 263 patients with focal epilepsy (temporal lobe epilepsy (TLE), n=178; extratemporal lobe epilepsy (ETLE), n=85) who underwent prolonged video-EEG monitoring during presurgical epilepsy evaluation were reviewed. Preoperative findings (TLE, n=16; ETLE, n=6) and postoperative outcomes (TLE, n=7) of patients with focal epilepsy with ictal body turning were assessed. For the evaluation of ictal body turning, two definitions were proposed. Nonversive body turning (NVBT) was used to denote at least a 90° nonforced (without tonic or clonic component) rotation of the upper (shoulder) and lower (hip) parts of the body around the body axis for a minimum of 3s. Versive body turning (VBT) was used to denote at least a 90° forced (with tonic or clonic component) rotation of the upper (shoulder) and lower (hip) parts of the body around the body axis for a minimum of 3s. Nonversive body turning was observed in 6% (n=11) of patients with TLE and 2% (n=2) of patients with ETLE. For VBT, these ratios were 5% (n=8) and 7% (n=6) for patients with TLE and ETLE, respectively. Nonversive body turning was frequently oriented to the same side as the epileptogenic zone (EZ) in TLE and ETLE seizures (76% and 80%, respectively). If the amount of NVBT was greater than 180°, then it was 80% to the same side in TLE seizures. Versive body turning was observed in 86% of the TLE seizures, and 55% of the ETLE seizures were found to be contralateral to the EZ. When present with head turning, NVBT ipsilateral to the EZ and VBT contralateral to the EZ were more valuable for lateralization. In TLE seizures, a significant correlation was found between the head turning and body turning onsets and durations. Our study demonstrated that ictal body turning is a rarely observed but reliable lateralization finding in TLE and ETLE seizures, which also probably has the same pathophysiological mechanism as head turning in TLE seizures.

Fly ash and bottom ash are coal combustion by-products (CCBPs) that are generated in large quanti... more Fly ash and bottom ash are coal combustion by-products (CCBPs) that are generated in large quantities throughout the world. It is often economical to dispose ash as mixtures rather than separately; that notwithstanding, only a few studies have been performed to investigate the behavior of fly and bottom ash mixtures, particularly those with high contents of fly ash. Also, there

Journal of Geotechnical and Geoenvironmental Engineering, 2009

... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 ... more ... instances in which it took longer than 2 hrs to satisfy the settlement rate criterion of 0.5 mm/hr, the next load increment was applied only after the difference in settlement rate between the ... “Fromstrain measurements to ... “Stiffness degradation and shear strength of silty sands.” Can ...

Steel slag is a by-product of steelmaking and refining processes. In 2006, 10-15 million metric t... more Steel slag is a by-product of steelmaking and refining processes. In 2006, 10-15 million metric ton of steel slag was generated in the U.S. Out of the total steel slag produced in the U.S. every year, about 50-70% is used as aggregate for road and pavement construction and approximately 15-40% is stockpiled in steel plants and eventually landfilled at slag disposal sites. Since current levels of steel slag stockpiling and landfilling are not sustainable, alternative geotechnical engineering applications for steel slag are being explored to alleviate the slag disposal problem and to help save dwindling natural resources. The main objectives of this research were to determine the geotechnical engineering properties of two types of steel slag generated from different steelmaking operations and to assess their potential use in subgrade stabilization and embankment construction. Samples of fresh and aged basic-oxygen-furnace (BOF) slag and of fresh electric-arc-furnace-ladle (EAF(L)) slag were characterized through a series of laboratory tests (specific gravity, grain-size analysis, X-ray diffraction, compaction, maximum and minimum density, large-scale direct shear, consolidated drained triaxial and swelling tests). The effects of gradation on the engineering properties of both fresh and aged steel slag samples were also investigated. Various mixtures of steel slag [BOF and EAF(L)] and Class-C fly ash were also investigated. The mixtures were prepared by adding 5 and 10% Class-C fly ash (by weight) to aged BOF slag and 5, 10 and 20% Class-C fly ash (by weight) to fresh EAF(L) slag. Unconfined compression tests were performed after various curing times to evaluate the strength gain characteristics of the mixtures. Long-term swelling tests were performed for compacted mixtures of both fresh and aged BOF slag and 10% Class-C fly ash (by weight) and for compacted mixtures of fresh EAF(L) slag and 5, 10 and 20% Class-C fly ash (by weight). The effect of adding 10% ground rubber (by weight) to fresh and aged BOF slag on the long-term swelling behavior of the mixtures was also investigated. The optimum moisture content and maximum dry unit weight of BOF slag were in the ranges of 4-8% and 19.5-21.8 kN/m 3 , respectively. The critical-state friction angle of fresh and aged BOF slags was in the 45.3°-48.1° range according to large-scale direct shear test results. Based on isotropically consolidated drained triaxial test (CIDTX) results, the peak friction angles of aged BOF slag (with minus 9.5 mm gradation) samples prepared at 90% relative compaction were equal to 47.3°, 45.2° and 43.5° at effective confining stresses of 50, 110 and 200 kPa, respectively. The optimum moisture content and maximum dry unit weight of EAF(L) slag were in the ranges of 10-13% and 16.8-20.0 kN/m 3 , respectively. The critical-state friction angle of fresh EAF(L) slag was equal to approximately 40.6° according to large-scale direct shear tests results. Compacted mixtures of both Class-C fly ash and BOF slag and of Class-C fly ash and EAF(L) slag showed excellent strength gain properties with time. Results of the long-term swelling tests on steel slag and Class-C fly ash mixtures showed that the addition of 10% Class-C fly ash suppresses the swelling of both BOF and EAF(L) slag samples to negligible levels. .