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Dive into the research topics where Okan Karahan is active.

Publication


Featured researches published by Okan Karahan.


Advances in Engineering Software | 2009

Comparison of artificial neural network and fuzzy logic models for prediction of long-term compressive strength of silica fume concrete

Fatih Özcan; Cengiz Duran Atiş; Okan Karahan; Erdal Uncuoğlu; Harun Tanyildizi

In this study, an artificial neural network (ANN) and fuzzy logic (FL) study were developed to predict the compressive strength of silica fume concrete. A data set of a laboratory work, in which a total of 48 concretes were produced, was utilized in the ANNs and FL study. The concrete mixture parameters were four different water-cement ratios, three different cement dosages and three partial silica fume replacement ratios. Compressive strength of moist cured specimens was measured at five different ages. The obtained results with the experimental methods were compared with ANN and FL results. The results showed that ANN and FL can be alternative approaches for the predicting of compressive strength of silica fume concrete.


Advances in Engineering Software | 2009

Predicting the compressive strength of ground granulated blast furnace slag concrete using artificial neural network

Cahit Bilim; Cengiz Duran Atiş; Harun Tanyildizi; Okan Karahan

In this study, an artificial neural networks study was carried out to predict the compressive strength of ground granulated blast furnace slag concrete. A data set of a laboratory work, in which a total of 45 concretes were produced, was utilized in the ANNs study. The concrete mixture parameters were three different water-cement ratios (0.3, 0.4, and 0.5), three different cement dosages (350, 400, and 450kg/m^3) and four partial slag replacement ratios (20%, 40%, 60%, and 80%). Compressive strengths of moist cured specimens (22+/-2^oC) were measured at 3, 7, 28, 90, and 360 days. ANN model is constructed, trained and tested using these data. The data used in the ANN model are arranged in a format of six input parameters that cover the cement, ground granulated blast furnace slag, water, hyperplasticizer, aggregate and age of samples and, an output parameter which is compressive strength of concrete. The results showed that ANN can be an alternative approach for the predicting the compressive strength of ground granulated blast furnace slag concrete using concrete ingredients as input parameters.


Construction and Building Materials | 2009

Influence of activator on the strength and drying shrinkage of alkali-activated slag mortar

Cengiz Duran Atiş; Cahit Bilim; Ozlem Celik; Okan Karahan


Materials & Design | 2011

The durability properties of polypropylene fiber reinforced fly ash concrete

Okan Karahan; Cengiz Duran Atiş


Construction and Building Materials | 2009

Properties of steel fiber reinforced fly ash concrete

Cengiz Duran Atiş; Okan Karahan


Materials & Design | 2013

Influence of admixtures on the properties of alkali-activated slag mortars subjected to different curing conditions

Cahit Bilim; Okan Karahan; Cengiz Duran Atiş; Serhan İlkentapar


Cement & Concrete Composites | 2008

The influence of aggregate type on the strength and abrasion resistance of high strength concrete

A. Kılıç; Cengiz Duran Atiş; A. Teymen; Okan Karahan; F. Özcan; Cahit Bilim; M. Özdemir


Construction and Building Materials | 2015

Very high strength (120 MPa) class F fly ash geopolymer mortar activated at different NaOH amount, heat curing temperature and heat curing duration

Cengiz Duran Atiş; Ela Bahşude Görür; Okan Karahan; Cahit Bilim; Serhan İlkentapar; Erion Luga


Construction and Building Materials | 2007

A comparative experimental investigation of concrete, reinforced-concrete and steel-fibre concrete pipes under three-edge-bearing test

Tefaruk Haktanir; Kamuran Ari; Fatih Altun; Okan Karahan


Construction and Building Materials | 2012

Effect of metakaolin content on the properties self-consolidating lightweight concrete

Okan Karahan; Khandaker M. Anwar Hossain; Erdogan Ozbay; Mohamed Lachemi; Emre Sancak

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Erdogan Ozbay

Mustafa Kemal University

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