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- MakaleYalnız künye2023Scopus SJRQ3Evaluation of Pozzolanic Activity of Two Different Types of C and F Fly Ashes with Fineness Factor
Sahin, Demet Demir; Cavusoglu, Ibrahim; Yilmaz, Ali Osman
Today, energy produced from coal is economical compared to other sources but it faces a very serious waste problem. However, these wastes are evaluated by using them as mineral additives in cement, which leads to lower cement costs, saving resources, producing environmentally friendly cement, reducing CO2 gas, and producing high-strength cement. In this work, the pozzolanic properties of different types of fly ash (Afşin Elbistan C type and Çayırhan F type) are investigated. The fly ashes used in the study are first subjected to the milling process (10, 20, 30, 45, and 60 minutes), and then the 28 and 90-day pozzolanic activity index tests of the milled and unmilled ashes are performed. The results obtained show that the 28-day pozzolanic activity value of the ashes subjected to 20-, 30-, 45-, and 60-minute milling times are higher than the value specified in the standard, compared to the unmilled and 10 min milled fly ash. In addition, for all fly ash samples, the 90-day pozzolanic activity index results show that while the pozzolanic activity index value of Çayırhan (ÇYH) fly ash is higher than the standard value, that of Afşin Elbistan (AE) fly ash is lower than standard. The outcomes of the present study show that the mechanical properties of the fly ash are generated by the burning of coal increase after milling process, and thus can be used as a mineral additive. With the effect of grinding, both fly ash increase the pozzolanic activity. The results are determined with the experimental results obtained.
AtıfScopus5WoS3
İncele - MakaleYalnız künye2023Scopus SJRQ2Effect of Reduced Fineness of Fly Ash Used on the Alkali–Silica Reaction (ASR) of Concrete
Eker, Hasan; Demir Şahin, Demet; Çullu, Mustafa
This study aimed to determine the effect of fly ash added to concrete with high calcium content (C class) and different fineness on durability properties such as the alkali–silica reaction (ASR). By substituting ultra-fine fly ash for cement at specific proportions in concrete mixes and increasing the fly ash fineness, fly ash filled the spaces between cement grains or aggregates in concrete and accelerated the hydration process. Thus, the mechanism of ASR development was reduced. Class C Afşin Elbistan ash was used and was ground in a ball mill for 0, 10, 20, 30, and 45 min, and Blaine fineness values of 1555, 1632, 2347, 2589, and 2766 cm2/g were obtained, respectively. For each fly ash fineness, the effect of mixtures with 10%, 30%, and 50% replacement of cement on the ASR mechanism was observed during curing periods of 3, 7, 14, and 28 days compared to concrete without fly ash admixture. Furthermore, the effect of the increased fineness and substitution rate of fly ash with high calcium content in cement on the microstructure was revealed by microscopic mineralogical images. The prepared fine fly ash added to concrete mixes at different replacement ratios showed ASR reducing properties compared to the concrete mix without additions. The fly ash fineness and the substitution rate in the concrete had a reducing effect on the ASR, and this effect resulted in values lower than the reference concrete value.
AtıfScopus21WoS21OpenAlex24İncele