Browsing by Author "Beglarigale, Ahsanollah"

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Citation Count: 5
Alkali-silica reaction of sanitary ware ceramic wastes utilized as aggregate in ordinary and high-performance mortars
(Elsevier Ltd, 2022) Tutkun,B.; Beglarigale,A.; Yazici,H.; İnşaat Mühendisliği / Civil Engineering
Waste management has been the foremost concern in the last decades. Utilizing sanitary ware ceramic (SWC) wastes in concrete has been found to be beneficial in terms of sustainability and cost in previous studies; however, deleterious alkali-silica reaction (ASR) potential of this waste aggregate, albeit it's high SiO2 content, has not been taken into account. This study aims to examine ASR potential of SWC wastes as well as the effects of permeability, w/c ratio, and reactive powder content of mixtures on the ASR-induced expansions in detail. Accelerated mortar bar, total and capillary water absorptions, and chloride ion penetration tests were conducted for %20, %40, %60, %80, and %100 replacement ratios at the first part of the study. The SWC aggregate showed ASR-induced expansions in “pessimum proportions”. With a 9-day delay, similar patterns (trends) of ASR expansions were observed in the mixtures with a w/c ratio of 0.3 as compared with those of 0.5 w/c ratio. While the ASR expansions had meaningful relations with the water absorption tests and w/c ratio, there was no noteworthy correlation with the rapid chloride ion penetration test results, since the SWC aggregate effected the properties of pore solution. The effect of the finer grains of the SWC aggregate on ASR was investigated in the second part of the study. For this purpose, the SWC aggregate finer than 250 µm was replaced with same sized limestone aggregate. The results revealed that the finer grains of SWC aggregate were responsible for the reductions observed in the first part of the study not due to “pessimum effect” phenomenon but rather to the pozzolanic activity of the finer grains. © 2021
Citation Count: 4
Alkali-silica reaction of sanitary ware ceramic wastes utilized as aggregate in ordinary and high-performance mortars
(Elsevier Sci Ltd, 2022) Tutkun, Bayram; Beglarigale, Ahsanollah; Yazici, Halit; İnşaat Mühendisliği / Civil Engineering
Waste management has been the foremost concern in the last decades. Utilizing sanitary ware ceramic (SWC) wastes in concrete has been found to be beneficial in terms of sustainability and cost in previous studies; however, deleterious alkali-silica reaction (ASR) potential of this waste aggregate, albeit it's high SiO2 content, has not been taken into account. This study aims to examine ASR potential of SWC wastes as well as the effects of permeability, w/c ratio, and reactive powder content of mixtures on the ASR-induced expansions in detail. Accelerated mortar bar, total and capillary water absorptions, and chloride ion penetration tests were conducted for %20, %40, %60, %80, and %100 replacement ratios at the first part of the study. The SWC aggregate showed ASR-induced expansions in "pessimum proportions". With a 9-day delay, similar patterns (trends) of ASR expansions were observed in the mixtures with a w/c ratio of 0.3 as compared with those of 0.5 w/c ratio. While the ASR expansions had meaningful relations with the water absorption tests and w/c ratio, there was no noteworthy correlation with the rapid chloride ion penetration test results, since the SWC aggregate effected the properties of pore solution. The effect of the finer grains of the SWC aggregate on ASR was investigated in the second part of the study. For this purpose, the SWC aggregate finer than 250 mu m was replaced with same sized limestone aggregate. The results revealed that the finer grains of SWC aggregate were responsible for the reductions observed in the first part of the study not due to "pessimum effect" phenomenon but rather to the pozzolanic activity of the finer grains.
Citation Count: 1
Corrosion Behavior of Rebars Embedded in Alkali-Activated and Conventional Reactive Powder Concretes
(Turkish Chamber Civil Engineers, 2020) Yigiter, Huseyin; Beglarigale, Ahsanollah; Aydin, Serdar; Baradan, Bulent; İnşaat Mühendisliği / Civil Engineering
The present study investigated the corrosion behavior of reinforcement bars embedded in alkali-activated (ARPC) and conventional (CRPC) reactive powder concretes. Corrosion progress in 3.5% NaCl solution, water and air environments were monitored up to 365 days. The physical and mechanical characteristics, such as water absorption, rapid chloride ion permeability, compressive and flexural strength, and corrosion characteristics, such as half cell potential and corrosion current intensity results were compared for ARPC and CRPC matrices. Even for the same mechanical performance, alkali-activated mortars were found to have a high permeable structure and an early depassivation of the rebars occurred. In the propagation stage of chloride induced corrosion, almost 13 times higher corrosion current intensity values were measured as well as earlier deterioration and cracking was observed for ARPC compared to CRPC.
Citation Count: 1
Corrosion behavior of rebars embedded in alkali-activated and conventional reactive powder concretes
(Turkish Chamber of Civil Engineers, 2020) Yiteter,H.; Beglarigale,A.; Aydin,S.; Baradan,B.; İnşaat Mühendisliği / Civil Engineering
The present study investigated the corrosion behavior of reinforcement bars embedded in alkali-activated (ARPC) and conventional (CRPC) reactive powder concretes. Corrosion progress in 3.5% NaCl solution, water and air environments were monitored up to 365 days. The physical and mechanical characteristics, such as water absorption, rapid chloride ion permeability, compressive and flexural strength, and corrosion characteristics, such as half cell potential and corrosion current intensity results were compared for ARPC and CRPC matrices. Even for the same mechanical performance, alkali-activated mortars were found to have a high permeable structure and an early depassivation of the rebars occurred. In the propagation stage of chloride induced corrosion, almost 13 times higher corrosion current intensity values were measured as well as earlier deterioration and cracking was observed for ARPC compared to CRPC. © 2020 Turkish Chamber of Civil Engineers. All rights reserved.
Citation Count: 0
Corrosion Performance of Various Reinforced Concretes Subjected to a Systematic Wetting-Drying Cycle Regime in Real Marine Environment
(Asce-amer Soc Civil Engineers, 2023) Beglarigale, Ahsanollah; Huseyin, Yigiter; Yazici, Halit; İnşaat Mühendisliği / Civil Engineering
This study contributes to the understanding of the chloride-induced corrosion of steel rebars embedded in various concretes. Concrete specimens were exposed to systematic wetting-drying cycles in real seawater via a platform installed on a pier. Various mixtures were designed using three different cement types and two binder dosages (therefore two water/cement ratios) with and without fly ash. The strength development and electrical conductivity of the mixtures were assessed prior to the cycles. The dimensional stability, flexural strength, compressive strength, and chloride penetration depth of plain concretes were scrutinized during the cycles. The corrosion processes of 360 RC specimens with three different cover thicknesses were monitored. The test results revealed that increasing the dosage of cement, and therefore decreasing the water/cement ratio, was a more effective corrosion-mitigation approach than was the utilization of fly ash or enhancing physical protection.
Citation Count: 30
Evaluation of enhanced autogenous self-healing ability of UHPC mixtures
(Elsevier Sci Ltd, 2021) Beglarigale, Ahsanollah; Eyice, Doga; Tutkun, Bayram; Yazici, Halit; İnşaat Mühendisliği / Civil Engineering
Enhancing and characterization of self-healing ability of ultra high performance concrete (UHPC) is the main aim of this study. The self-healing mechanisms of macro/micro cracks were investigated through different techniques with some novel procedures. Two different mix designs have been considered to increase the amount of unreacted particles in the matrix. In spite of the positive effect of supplementary cementitious materials (SCM) on self-healing ability of UHPC, it was observed that the detected self-healing ratios depend on critical parameters such as damage type/level and the methods used to verify the phenomenon of self-healing. Depending on the composition of the UHPC mixtures, the age of specimens and the assessing method, up to 70-76% recoveries were obtained in the compressive strength and permeability of specimens pre-loaded up to -400% of their corresponding compressive strength. In addition, up to 88-100% crack sealing was observed in the pre-cracked UHPC specimens assessed via various methods. (C) 2021 Elsevier Ltd. All rights reserved.
Citation Count: 0
Microencapsulation of Isophorone Diisocyanate with Silica Shell
(Springer Science and Business Media B.V., 2021) Beglarigale,A.; Eyice,D.; Seki,Y.; Yazıcı,H.; İnşaat Mühendisliği / Civil Engineering
In several studies, Isophorone diisocyanate (IPDI), a monomeric aliphatic diisocyanate, has been microencapsulated with various polymeric shells for self-healing purposes in polymer-based materials. In this study, for the first time, isophorone diisocyanate was microencapsulated with silica shell via interfacial polycondensation of a silica precursor (TEOS). The shell materials of the IPDI-loaded microcapsules reported in the literature are polymeric (organic). It is known from the literature that silica shell can chemically and physically bonded to cementitious matrices, allowing the microcapsules to remain stable for years without deterioration. Essential parameters such as the amounts of core material (IPDI), shell-forming material, and surfactant as well as the stirring speeds were investigated through yield, optical microscopy, SEM, TGA, and FTIR analyses. Promising results were obtained in the process of microencapsulation of isophorone diisocyanate with silica shell. The optimum core material/shell-forming material, oil phase/aqueous phase, and surfactant/oil ratios were found to be 1.0, 0.18, and 0.08, respectively. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Citation Count: 4
Novel Test Method for Assessing Bonding Capacity of Self-Healing Products in Cementitious Composites
(Asce-amer Soc Civil Engineers, 2019) Beglarigale, Ahsanollah; Vahedi, Houten; Eyice, Doga; Yazici, Halit; İnşaat Mühendisliği / Civil Engineering
Many tests and methods can be used to assess or verify the self-healing mechanisms of cement-based materials. This study, which is part of wider project, deals with the development and application of a test method for studying the self-healing ability of cementitious composites. The principle of this method lies in the bonding capacity of self-healing products under direct tension loads. A specially designed cylinder specimen was split after 7 days of water curing, and then the two parts of the split specimen were carefully put together immediately. A connector apparatus was designed to keep the surface of each part connected to each other with equal pressure for the "healing" process in water. After 30 days, the specimens were tested by a special direct tension test method to evaluate the bond loads. In addition, the crack-closing ratios were monitored on precracked disc-shaped specimens. The bond loads of 7 different ultra-high-performance concrete (UHPC) mixtures were compared with the crack-closing ratios. The healing process in the novel test, which simulated the self-healing of very narrow cracks, was observed to differ from the crack-closing test method. Considerable bond loads were obtained in both fly ash (308 N) and ground granulated blast furnace slag (GGBFS) (210 N) bearing mixtures. Additionally, the maximum crack-closing ratio (100%) was observed in the GGBFS bearing mixture. (c) 2019 American Society of Civil Engineers.
Citation Count: 14
Sodium silicate/polyurethane microcapsules synthesized for enhancing self-healing ability of cementitious materials: Optimization of stirring speeds and evaluation of self-healing efficiency
(Elsevier, 2021) Beglarigale, Ahsanollah; Eyice, Doga; Seki, Yoldas; Yalcinkaya, Caglar; Copuroglu, Oguzhan; Yazici, Halit; İnşaat Mühendisliği / Civil Engineering
In this study, stirring speeds during the synthesizing process of the sodium silicate/polyurethane microcapsules were optimized. The yield values of micmcapsules at different stirring rates were evaluated. Based on the yield values and shape of microcapsules, optimized microcapsules were obtained. The measurements of the shell thickness of microcapsules were performed on the fractured microcapsules by using scanning electron microscopy. The optimized micmcapsules were further characterized by means of optical microscopy and nanoindentation. Load vs. displacement and modulus of elasticity vs. displacement characteristics of the microcapsules were obtained. The average modulus of elasticity was found to be 633 MPa. The self-healing efficiency of the optimized micmcapsules was evaluated by means of compressive strength tests. The incorporation of micmcapsules reduced the compressive strength of fiber-reinforced mortar by 12-22%. However, it was observed that the microcapsules enhanced the self-healing capacity (recovery in compressive strength) of the mortar.