Browsing by Author "Tutkun, Bayram"

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Citation Count: 4
Alkali-silica reaction of sanitary ware ceramic wastes utilized as aggregate in ordinary and high-performance mortars
(Elsevier Sci Ltd, 2022) Beglarigale, Ahsanollah; 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: 30
Evaluation of enhanced autogenous self-healing ability of UHPC mixtures
(Elsevier Sci Ltd, 2021) Beglarigale, Ahsanollah; Beglarigale, Ahsanollah; 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.