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- MakaleYalnız künye2020Scopus SJRQ3A dynamic segregation test method for heavyweight concrete: Density variation method
Süleyman Gökçe, H.; Andiç-Çakir, Ö.
Several segregation evaluation methods have been developed for concrete; however, none of them have been specially focused on heavyweight concrete, which has more of a tendency toward segregation because of differences in density of paste matrix to heavy aggregate. Thus, for heavyweight concrete, the segregation may be determined by measuring the difference density in a vertical direction. In this study, a simple reliable method, i.e., the density variation method, that considers the variation in vertical layers of the concrete is modeled to assess dynamic segregation of heavyweight concrete. In addition, 35 heavyweight concrete mixtures with high consistency were designed with various mixing parameters, and the results were compared with the model findings. The suggested test method was also compared with a conventional method (column segregation test by wet-sieving), and an equivalent segregation limit was determined. A strong linear relation (R2: 0.86) was found between the density variation method and column segregation test, and a segregation coefficient limit for segregation of heavyweight concrete is recommended as 1.7 %.
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İncele - MakaleYalnız künye2019Scopus SJRQ1Bleeding characteristics of high consistency heavyweight concrete mixtures
Gökçe, H. Süleyman; Andiç-Çakır, Özge
Bleeding, a type of static segregation derives from density difference of concrete ingredients in fresh state. Due to having this difference higher than normal weight counterparts, heavyweight concrete is more susceptible to bleeding, thus, this type of concrete is commonly produced in low slump values. In order to give a response to advances and demands in concrete technology, heavyweight concrete mixtures with high slump values were designed at various mixture characteristics, and their bleeding characteristics were researched in the study. For this purpose, totally, thirty-five concrete mixtures with ≥150 mm slump values were produced by using common cement replacement materials (silica fume and fly ash), viscosity modifier, and various water/binder ratios at two binder dosages. The mixtures showed excessive bleeding capacities ranged from 0 to 11.7% and bleeding rates ranged from 0 to 5.1 kg/m2/h. Silica fume was found as the most effective admixture for reducing or elimination of the bleeding. Bleeding time generally shorten at high binder content and at high water/binder ratio. It was observed that the bleeding adversely affects the hardened characteristics of heavyweight concrete mixtures.
AtıfScopus62WoS54OpenAlex59İncele