Ph.D. Tezi Görüntüleme
The performance of concretes and mortars produced using different mineral additives isinvestigated in this study. In this context, three series of concrete mixtures containing of 10%
silica fume, 20% fly ash and 20% granulated blast furnace slag were produced. Mixtureswithout mineral additives were also produced for making comparisons. Totally 250 specimens
of 15 cm cubes were prepared and they were kept in 2% sodium sulfate and magnesium sulfatesolutions, seawater provided from Karadeniz and in the tap water, respectively. At certain
intervals, concrete specimens exposed to sulfates were examined for surface hardness,ultrasound measurements and compressive strength. Meanwhile, the specimens were
periodically monitored for surface deterioration. Within the context of experimental program,mortars without mineral additives, with silica fume, with fly ash and with granulated blast
furnace slag were produced and 4x4x16 cm prisms were prepared. The addition rate of mineraladmixtures to mortar was 20% in all cases. The mortar prisms prepared were kept in 2%
magnesium sulfate solution at room temperature, at 5oC and at 40oC throughout the testingprogram.
Concretes with blast furnace slag cured in standard curing condition yielded the higheststrength. This is followed by concretes with silica fume at early ages and concretes with fly ash
at later ages. Concretes without mineral additives yielded the lowest strength throughoutexperimentation. The deterioration pattern of concretes subjected to magnesium sulfate was a
combination of surface softening and cracking, while concretes subjected to sodium sulfatesolution have indicated a similar deterioration pattern without surface softening. The mortar
prisms immersed in magnesium sulfate solution at room temperature have indicated adeterioration pattern of disintegration. In addition to findings given above, some additional
findings obtained from the study may be underlined that mineral admixtures have increased theperformance of concrete subjected to sulfate solutions and the deterioration mechanism
observed in the mortar prisms has indicated a different pattern depending on the temperature.Key words: Fly ash, Granulated blast furnace slag, Silica fume, Sulfate attack, Seawater,
Performance, Tobermorite, Ettrengite, Thaumasite.