Olawale Ayinde - Academia.edu (original) (raw)
Papers by Olawale Ayinde
Ksce Journal of Civil Engineering, Apr 6, 2022
Computers and Concrete, Feb 25, 2017
Materials & Design, 2017
In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ... more In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ductile iron pipe in a flowing solution, two types of ductile iron pipe specimens lined with ordinary-and 40% slag-cement mortar are firstly prepared, then, an accelerated leaching experiment on the prepared specimens is carried out by using a 6M ammonium chloride solution at a flow rate of 0.3m/s. The parameters of linings at different leaching times, such as porosity, pore size distribution, phase composition and Calcium-Silicon (Ca/Si) ratio, were analyzed by using the saturation-drying weighing method, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy in back scattered electron mode (ESEM-BSE) measurements. Results show that, the mixture of 40% slag in cement-mortar lining can reduce its initial porosity and Calcium-Silicon ratio, and improve its pore size distribution and phase composition. In the accelerated leaching process, the porosity, phase composition and Calcium-Silicon ratio of the slag-cement-mortar lining with 40% slag have smaller change than that of the ordinary-cement-mortar lining without slag, and it indicates that the addition of slag can effectively improve the calcium leaching resistance of cement-mortar lining in ductile iron pipes in water supply engineering.
Construction and Building Materials, Dec 1, 2016
In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the lea... more In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the leaching behavior of cement-based material and its corrosion resistance in water environments, an accelerated calcium leaching experiment on a slice specimen with slag-cement pastes in 6M NH 4 Cl solution was carried out. Using the saturation-drying weighing method, X-ray diffraction (XRD) and the scanning electron microscope (SEM/EDS) measurement, the influences of water-binder ratio and slag content on the porosity, phase composition, microstructure morphology and Calcium-Silicon ratio of slag-cement pastes in the process of calcium leaching were analyzed. Results show that, compared to cement pastes without slag, the slag-cement paste with the appropriate slag content has a low rate of microstructure deterioration and a good leaching resistance. The optimum slag contents in slag-cement pastes are respectively 40% and 50% corresponding to the low and high water-binder ratio. The porosity, Calcium-Silicon ratio and microstructure morphology of slag-cement pastes exhibit small change in the process of accelerating leaching, and this indicates that the slag-cement pastes with the optimum slag content can provide the best performance of calcium leaching resistance in the soft-water environment.
Ocean Engineering, Sep 1, 2017
This paper numerically simulates time-dependent mechanical behaviors, such as stress redistributi... more This paper numerically simulates time-dependent mechanical behaviors, such as stress redistribution and bearing capacity degradation, of concrete subjected to the coupled axial loading and sulfate attack. Based on Fick's law and chemical reaction kinetics, a diffusion-reaction model was proposed to obtain the spatial and time-dependent concentration distribution of sulfate ion, gypsum and ettringite. From previous study, a chemical damage, characterized by the volumetric expansion from ettringite formation, is introduced to reflect the influence of sulfate attack on concrete performance. Furthermore, using the plasticity theory and damage mechanics, a coupled chemo-mechanical damage constitutive model was determined by introducing the chemical damage. Finally, a concrete prism is regarded as a research object, to investigate the time-dependent stress and bearing capacity degradation of concrete structures subjected to the coupled axial compression and sulfate attack.
KSCE Journal of Civil Engineering, 2022
Journal of Sustainable Cement-Based Materials, 2020
Aliyu (2020): Electrochemical investigation on the influence of sulfates on chloride-induced corr... more Aliyu (2020): Electrochemical investigation on the influence of sulfates on chloride-induced corrosion of steel bar in cement-based materials, Journal of Sustainable Cement-Based Materials,
Computers and Concrete, 2017
Materials & Design, 2017
In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ... more In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ductile iron pipe in a flowing solution, two types of ductile iron pipe specimens lined with ordinary-and 40% slag-cement mortar are firstly prepared, then, an accelerated leaching experiment on the prepared specimens is carried out by using a 6M ammonium chloride solution at a flow rate of 0.3m/s. The parameters of linings at different leaching times, such as porosity, pore size distribution, phase composition and Calcium-Silicon (Ca/Si) ratio, were analyzed by using the saturation-drying weighing method, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy in back scattered electron mode (ESEM-BSE) measurements. Results show that, the mixture of 40% slag in cement-mortar lining can reduce its initial porosity and Calcium-Silicon ratio, and improve its pore size distribution and phase composition. In the accelerated leaching process, the porosity, phase composition and Calcium-Silicon ratio of the slag-cement-mortar lining with 40% slag have smaller change than that of the ordinary-cement-mortar lining without slag, and it indicates that the addition of slag can effectively improve the calcium leaching resistance of cement-mortar lining in ductile iron pipes in water supply engineering.
Construction and Building Materials, 2016
In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the lea... more In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the leaching behavior of cement-based material and its corrosion resistance in water environments, an accelerated calcium leaching experiment on a slice specimen with slag-cement pastes in 6M NH 4 Cl solution was carried out. Using the saturation-drying weighing method, X-ray diffraction (XRD) and the scanning electron microscope (SEM/EDS) measurement, the influences of water-binder ratio and slag content on the porosity, phase composition, microstructure morphology and Calcium-Silicon ratio of slag-cement pastes in the process of calcium leaching were analyzed. Results show that, compared to cement pastes without slag, the slag-cement paste with the appropriate slag content has a low rate of microstructure deterioration and a good leaching resistance. The optimum slag contents in slag-cement pastes are respectively 40% and 50% corresponding to the low and high water-binder ratio. The porosity, Calcium-Silicon ratio and microstructure morphology of slag-cement pastes exhibit small change in the process of accelerating leaching, and this indicates that the slag-cement pastes with the optimum slag content can provide the best performance of calcium leaching resistance in the soft-water environment.
Ocean Engineering, 2017
This paper numerically simulates time-dependent mechanical behaviors, such as stress redistributi... more This paper numerically simulates time-dependent mechanical behaviors, such as stress redistribution and bearing capacity degradation, of concrete subjected to the coupled axial loading and sulfate attack. Based on Fick's law and chemical reaction kinetics, a diffusion-reaction model was proposed to obtain the spatial and time-dependent concentration distribution of sulfate ion, gypsum and ettringite. From previous study, a chemical damage, characterized by the volumetric expansion from ettringite formation, is introduced to reflect the influence of sulfate attack on concrete performance. Furthermore, using the plasticity theory and damage mechanics, a coupled chemo-mechanical damage constitutive model was determined by introducing the chemical damage. Finally, a concrete prism is regarded as a research object, to investigate the time-dependent stress and bearing capacity degradation of concrete structures subjected to the coupled axial compression and sulfate attack.
Asian Journal of Civil Engineering
Concrete structures built in marine environment are susceptible to attack by chemicals such as ch... more Concrete structures built in marine environment are susceptible to attack by chemicals such as chloride which diffuses into concrete structures and attack the reinforcements embedded in reinforced structures and break down the reinforcement protective layer. This paper presents the use of Abaqus Finite Element Analysis software in Analyzing the processes involved in concrete structure degradation from chloride diffusion to concrete cracking. Mass diffusion, Faraday's law and the Extended Finite Element Method (XFEM) were used to simulate chloride diffusion, mass loss from steel corrosion and corrosion product expansion and concrete cover cracking simultaneously, while the pressure due to the tensile stress generated by corrosion product was idealized as radial displacements. Obtained results show an increasing chloride concentration with time, but reduction with depth of penetration, while an obvious crack pattern was obtained.
Concrete structures in marine environment are susceptible to chloride attack, where chloride diff... more Concrete structures in marine environment are susceptible to chloride attack, where chloride diffusion results in the corrosion of steel bar and further lead to the cracking of concrete cover. This process causes structural deterioration and affects the response of concrete structures to different forms of loading. This paper presents the use of ABAQUS Finite Element Software in simulating the processes involved in concrete\'s structural degradation from chloride diffusion to steel corrosion and concrete cover cracking. Fick\'s law was used for the chloride diffusion, while the mass loss from steel corrosion was obtained using Faraday\'s law. Pressure generated by steel corrosion product at the concrete-steel interface was modeled by applying uniform radial displacements, while concrete smeared cracking alongside the Extended Finite Element Method (XFEM) was used for concrete cover cracking simulation. Results show that, chloride concentration decreases with penetration ...
Ksce Journal of Civil Engineering, Apr 6, 2022
Computers and Concrete, Feb 25, 2017
Materials & Design, 2017
In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ... more In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ductile iron pipe in a flowing solution, two types of ductile iron pipe specimens lined with ordinary-and 40% slag-cement mortar are firstly prepared, then, an accelerated leaching experiment on the prepared specimens is carried out by using a 6M ammonium chloride solution at a flow rate of 0.3m/s. The parameters of linings at different leaching times, such as porosity, pore size distribution, phase composition and Calcium-Silicon (Ca/Si) ratio, were analyzed by using the saturation-drying weighing method, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy in back scattered electron mode (ESEM-BSE) measurements. Results show that, the mixture of 40% slag in cement-mortar lining can reduce its initial porosity and Calcium-Silicon ratio, and improve its pore size distribution and phase composition. In the accelerated leaching process, the porosity, phase composition and Calcium-Silicon ratio of the slag-cement-mortar lining with 40% slag have smaller change than that of the ordinary-cement-mortar lining without slag, and it indicates that the addition of slag can effectively improve the calcium leaching resistance of cement-mortar lining in ductile iron pipes in water supply engineering.
Construction and Building Materials, Dec 1, 2016
In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the lea... more In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the leaching behavior of cement-based material and its corrosion resistance in water environments, an accelerated calcium leaching experiment on a slice specimen with slag-cement pastes in 6M NH 4 Cl solution was carried out. Using the saturation-drying weighing method, X-ray diffraction (XRD) and the scanning electron microscope (SEM/EDS) measurement, the influences of water-binder ratio and slag content on the porosity, phase composition, microstructure morphology and Calcium-Silicon ratio of slag-cement pastes in the process of calcium leaching were analyzed. Results show that, compared to cement pastes without slag, the slag-cement paste with the appropriate slag content has a low rate of microstructure deterioration and a good leaching resistance. The optimum slag contents in slag-cement pastes are respectively 40% and 50% corresponding to the low and high water-binder ratio. The porosity, Calcium-Silicon ratio and microstructure morphology of slag-cement pastes exhibit small change in the process of accelerating leaching, and this indicates that the slag-cement pastes with the optimum slag content can provide the best performance of calcium leaching resistance in the soft-water environment.
Ocean Engineering, Sep 1, 2017
This paper numerically simulates time-dependent mechanical behaviors, such as stress redistributi... more This paper numerically simulates time-dependent mechanical behaviors, such as stress redistribution and bearing capacity degradation, of concrete subjected to the coupled axial loading and sulfate attack. Based on Fick's law and chemical reaction kinetics, a diffusion-reaction model was proposed to obtain the spatial and time-dependent concentration distribution of sulfate ion, gypsum and ettringite. From previous study, a chemical damage, characterized by the volumetric expansion from ettringite formation, is introduced to reflect the influence of sulfate attack on concrete performance. Furthermore, using the plasticity theory and damage mechanics, a coupled chemo-mechanical damage constitutive model was determined by introducing the chemical damage. Finally, a concrete prism is regarded as a research object, to investigate the time-dependent stress and bearing capacity degradation of concrete structures subjected to the coupled axial compression and sulfate attack.
KSCE Journal of Civil Engineering, 2022
Journal of Sustainable Cement-Based Materials, 2020
Aliyu (2020): Electrochemical investigation on the influence of sulfates on chloride-induced corr... more Aliyu (2020): Electrochemical investigation on the influence of sulfates on chloride-induced corrosion of steel bar in cement-based materials, Journal of Sustainable Cement-Based Materials,
Computers and Concrete, 2017
Materials & Design, 2017
In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ... more In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ductile iron pipe in a flowing solution, two types of ductile iron pipe specimens lined with ordinary-and 40% slag-cement mortar are firstly prepared, then, an accelerated leaching experiment on the prepared specimens is carried out by using a 6M ammonium chloride solution at a flow rate of 0.3m/s. The parameters of linings at different leaching times, such as porosity, pore size distribution, phase composition and Calcium-Silicon (Ca/Si) ratio, were analyzed by using the saturation-drying weighing method, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy in back scattered electron mode (ESEM-BSE) measurements. Results show that, the mixture of 40% slag in cement-mortar lining can reduce its initial porosity and Calcium-Silicon ratio, and improve its pore size distribution and phase composition. In the accelerated leaching process, the porosity, phase composition and Calcium-Silicon ratio of the slag-cement-mortar lining with 40% slag have smaller change than that of the ordinary-cement-mortar lining without slag, and it indicates that the addition of slag can effectively improve the calcium leaching resistance of cement-mortar lining in ductile iron pipes in water supply engineering.
Construction and Building Materials, 2016
In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the lea... more In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the leaching behavior of cement-based material and its corrosion resistance in water environments, an accelerated calcium leaching experiment on a slice specimen with slag-cement pastes in 6M NH 4 Cl solution was carried out. Using the saturation-drying weighing method, X-ray diffraction (XRD) and the scanning electron microscope (SEM/EDS) measurement, the influences of water-binder ratio and slag content on the porosity, phase composition, microstructure morphology and Calcium-Silicon ratio of slag-cement pastes in the process of calcium leaching were analyzed. Results show that, compared to cement pastes without slag, the slag-cement paste with the appropriate slag content has a low rate of microstructure deterioration and a good leaching resistance. The optimum slag contents in slag-cement pastes are respectively 40% and 50% corresponding to the low and high water-binder ratio. The porosity, Calcium-Silicon ratio and microstructure morphology of slag-cement pastes exhibit small change in the process of accelerating leaching, and this indicates that the slag-cement pastes with the optimum slag content can provide the best performance of calcium leaching resistance in the soft-water environment.
Ocean Engineering, 2017
This paper numerically simulates time-dependent mechanical behaviors, such as stress redistributi... more This paper numerically simulates time-dependent mechanical behaviors, such as stress redistribution and bearing capacity degradation, of concrete subjected to the coupled axial loading and sulfate attack. Based on Fick's law and chemical reaction kinetics, a diffusion-reaction model was proposed to obtain the spatial and time-dependent concentration distribution of sulfate ion, gypsum and ettringite. From previous study, a chemical damage, characterized by the volumetric expansion from ettringite formation, is introduced to reflect the influence of sulfate attack on concrete performance. Furthermore, using the plasticity theory and damage mechanics, a coupled chemo-mechanical damage constitutive model was determined by introducing the chemical damage. Finally, a concrete prism is regarded as a research object, to investigate the time-dependent stress and bearing capacity degradation of concrete structures subjected to the coupled axial compression and sulfate attack.
Asian Journal of Civil Engineering
Concrete structures built in marine environment are susceptible to attack by chemicals such as ch... more Concrete structures built in marine environment are susceptible to attack by chemicals such as chloride which diffuses into concrete structures and attack the reinforcements embedded in reinforced structures and break down the reinforcement protective layer. This paper presents the use of Abaqus Finite Element Analysis software in Analyzing the processes involved in concrete structure degradation from chloride diffusion to concrete cracking. Mass diffusion, Faraday's law and the Extended Finite Element Method (XFEM) were used to simulate chloride diffusion, mass loss from steel corrosion and corrosion product expansion and concrete cover cracking simultaneously, while the pressure due to the tensile stress generated by corrosion product was idealized as radial displacements. Obtained results show an increasing chloride concentration with time, but reduction with depth of penetration, while an obvious crack pattern was obtained.
Concrete structures in marine environment are susceptible to chloride attack, where chloride diff... more Concrete structures in marine environment are susceptible to chloride attack, where chloride diffusion results in the corrosion of steel bar and further lead to the cracking of concrete cover. This process causes structural deterioration and affects the response of concrete structures to different forms of loading. This paper presents the use of ABAQUS Finite Element Software in simulating the processes involved in concrete\'s structural degradation from chloride diffusion to steel corrosion and concrete cover cracking. Fick\'s law was used for the chloride diffusion, while the mass loss from steel corrosion was obtained using Faraday\'s law. Pressure generated by steel corrosion product at the concrete-steel interface was modeled by applying uniform radial displacements, while concrete smeared cracking alongside the Extended Finite Element Method (XFEM) was used for concrete cover cracking simulation. Results show that, chloride concentration decreases with penetration ...