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Article Citation - WoS: 10Citation - Scopus: 9Bacteria-Induced Cementation in Sandy Soils(Taylor & Francis inc, 2015) Gurbuz, Ayhan; Sari, Yasin Dursun; Yuksekdag, Zehra NurBacteria-induced calcite precipitation (BICP) is a promising technique that utilizes bacteria to form calcite precipitates throughout the soil matrix, leading to an increase in soil strength and stiffness. This research investigated BICP in two types of sands under sterile and nonsterile conditions. Bacteria formation and BICP in the sterilized sand specimens are higher than those in the nonsterilized sand specimens. The development of calcite with time is initially greater for the sand specimens containing calcite. Scanning electron microscope imaging allowed the detection of cementation from calcite precipitation on the surface and pores of the sand matrix. The effects of injecting nutrient mediums and bacteria into the specimens, as well as pH of soil samples on BICP were investigated. The bearing capacity of biologically treated vs. untreated sand specimens were determined especially by laboratory foundation loading tests.Article Citation - WoS: 4Evaluation of Boron Ore in Cement Production(Taylor & Francis inc, 2012) Yesilmen, Seda; Gurbuz, AyhanA new genre of high belite cement named boron-modified active belite (BAB) cement that was developed using byproduct of boric acid production was investigated. The cement proved superior in compressive strength and permeability characteristics in the previous studies. Long term storage of cement is known to alter the mechanical properties of concrete made with the aged cement. The article investigated the BAB cement in aged condition-stored in silos for about three years-variations of mechanical and physical properties of specimens during a one-year period. An additional comparison is also performed with specimens cast using fresh Ordinary Portland Cement (OPC) of the same grade in order to present the development of mechanical and physical properties in a qualitative manner. Lower 28 day compressive strength values are observed for BAB cement compared to OPC specimens; however, higher rate of strength development of BAB cement resulting from high belite content led to comparable long term strength values with OPC specimens.
