Civil Engineering / İnşaat Mühendisliği

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Browsing Civil Engineering / İnşaat Mühendisliği by Author "Ahari, Reza Saleh"

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    Article
    Citation - WoS: 18
    Citation - Scopus: 22
    Influence of Thixotropy Determined by Different Test Methods on Formwork Pressure of Self-Consolidating Concrete
    (Elsevier Ltd., 2018-06) Tuyan, Murat; Ahari, Reza Saleh; Erdem, Tahir Kemal; Andiç Çakır, Özge; Ramyar, Kambiz
    In this experimental study, the influence of thixotropy determined by different test methods on the formwork pressure of self-consolidating concrete (SCC) with varying compositions was investigated. In order to determine the effect of water/binder (w/b) ratio, slump flow diameter and coarse aggregate/total aggregate (CA/TA) ratio on thixotropy and formwork pressure of SCC, fifteen concrete mixtures were prepared. Four different test methods i.e., “structural break-down area” (SBDA), “break-down percentage” (BDP), “drop in apparent viscosity” (DAV) and “yield value at rest” (YVR) were performed to determine the thixotropy of the SCC mixtures. Test results showed that the SBDA, DAV and YVR methods were more appropriate to evaluate the thixotropy of SCC than the BDP method. A strong correlation between thixotropy and formwork pressure was found using SBDA, DAV and YVR methods in SCC mixtures having low w/b ratio. There was a strong relationship between thixotropy determined by SBDA, BDP and DAV methods and formwork pressure in low slump flow SCC mixtures, while thixotropy determined by the YVR method showed good correlation with the formwork pressure in SCC mixtures having high slump flow values. Finally, new models were developed to estimate the formwork pressure of all kinds of mixtures as a function of thixotropy and time. The models were found to be successful for each of the thixotropy measurement method.
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    Article
    Citation - WoS: 100
    Citation - Scopus: 125
    Thixotropy and Structural Breakdown Properties of Self Consolidating Concrete Containing Various Supplementary Cementitious Materials
    (Elsevier Ltd., 2015-05) Ahari, Reza Saleh; Erdem, Tahir Kemal; Ramyar, Kambiz
    Abstract In this study, thixotropy and structural breakdown of 57 self-consolidating concrete (SCC) mixtures containing various supplementary cementitious materials (SCM) were investigated by different approaches. The effects of SCM type and content on high range water reducer demand and plastic viscosity were also studied. For these purposes, various amounts of silica fume (SF), metakaolin (MK), Class F fly ash (FAF), Class C fly ash (FAC) and granulated blast-furnace slag (BFS) were utilized in binary, ternary, and quaternary cementitious blends in three water/binder (w/b) ratios. Results showed that except BFS, use of SCM in SCC mixtures increased thixotropy values in comparison with the mixtures containing only portland cement (PC). Good correlations were established between structural breakdown area and drop in apparent viscosity values for all w/b ratios. The different methods used to evaluate the thixotropy and structural breakdown got more consistent with each other as w/b decreased.