Browsing by Author "Ramroom A.A."

Now showing 1 - 3 of 3

INVESTIGATION AND TAGUCHI OPTIMIZATION OF FIRE RESISTANCE IN ULTRA-HIGH PERFORMANCE CONCRETE (UHPC) PRODUCED USING MINERAL ADDITIVES
(2022-01-01) Memiş S.; Ramroom A.A.
In this study, the effects of silica fume (SF), fly ash (FA) and granulated blast furnace slag (GBFS) on the design and fire resistance properties of ultra-high performance concrete (UHPC) were analyzed using the Taguchi L16 method. Samples were exposed to temperatures of 300 °C, 450 °C and 600 °C. The composition of the UHPC was: sand/binder ratio = 1, water/binder ratio = 0.19, Polycarboxylate superplasticizer (PCE) /binder ratio = 3.5%, pozzolanic (SF, FA and GBFS)/binder ratio = (0, 10, 15, 20)% and steel fibers = 1% by volume, and a Taguchi L16 program was prepared that consisted of 240 samples (40x40x160mm). The high-temperature properties of the UHPC samples were evaluated. Because several mixtures could withstand a temperature of 450 °C, it was determined that the losses were more effective when the highest temperature reached was greater than or equal to 600 °C, and the twelve mixtures are damaged by breaking them up. When the actual values obtained in the verification test were examined, it was determined that the results were sufficient for the compressive and flexural strength and physical properties of the concrete under various heating conditions and the Taguchi optimization was successfully implemented.
Investigation of the ideal mixing ratio and steel fiber additive in ultra high performance concrete (Uhpc)
(2020-01-01) Memiş S.; Ramroom A.A.
Ultra high performance concrete (UHPC) generally has low workability due to the fact that it is a material with low water/cement (w/c) ratio and contains fiber in it. Therefore, adding a superplasticizer (SP) in its production may be a solution, so that it can self-compress, but there may be an overdosing problem. This research, conducted in two stages to determine ideal UPHC mixture, consisted of the first stage involving the determination of the sand/binder (s/b) ratio and the two stages, which included the determination of the ideal steel fiber ratio. To achieve ultra-high performance, the w/c ratio was reduced to 0.2 and the steel fiber was increased to a maximum of 2%. The fresh and hardened properties of UPHC were examined, for better workability their flow diameters and also compressive strengths, flexural strengths, densities, water absorption rates, total voids were determined in UPHC mixtures. It has been determined that the maximum strength can reach about 110 MPa without steel fiber reinforcement, but 130-140 MPa strengths can be achieved if up to 2% steel fiber is added to the mixtures. It has been found that the strength of the UHPC is related to the s/b ratio and the fiber volume used and that the UHPCs can be obtained when the ideal ratios are taken into account.
Investigation of the use of waste mineral additives in ultra-high-performance concrete
(2023-01-01) Memiş S.; Ramroom A.A.