Ph.D. Tezi Görüntüleme

Student: İlker USTABAŞ
Supervisor: Prof. Dr. Şakir ERDOĞDU
Department: İnşaat Mühendisliği
Institution: Graduate School of Natural and Applied Sciences
University: Karadeniz Technical University, Turkey
Title of the Thesis: Performance Of Minarel Incorporated Concrete And Mortar Exposed To Sodium And Magnesium Sulfate
Level: Ph.D.
Acceptance Date: 9/5/2008
Number of Pages: 130
Registration Number: Di635

      The performance of concretes and mortars produced using different mineral additives is

investigated 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. Mixtures

without 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 sulfate

solutions, 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 mineral

admixtures 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 testing


      Concretes with blast furnace slag cured in standard curing condition yielded the highest

strength. 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 throughout

experimentation. The deterioration pattern of concretes subjected to magnesium sulfate was a

      combination of surface softening and cracking, while concretes subjected to sodium sulfate

solution have indicated a similar deterioration pattern without surface softening. The mortar

      prisms immersed in magnesium sulfate solution at room temperature have indicated a

deterioration pattern of disintegration. In addition to findings given above, some additional

      findings obtained from the study may be underlined that mineral admixtures have increased the

performance 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.