Ozlem Celik Sola

The Effects of Different Types of Fly Ash on the Compressive Strength Properties of Briquettes

The aim of this study is to evaluate the effect of the different types of fly ash on the compressive strength properties of sintered briquettes. Thermal gravimetric (TG) analysis was carried out. The chemical composition and physical properties of the materials used were determined. Particle size distribution and microstructure elemental analyses of the materials used were carried out by a particle size analyzer (Mastersizer) and a scanning electron microscope (SEM-EDS). Following the characterization of the materials, briquettes were prepared by sintering at different temperatures. Compressive strength test results of the briquette samples indicated that briquettes with a compressive strength value of 47.45 N/mm2 can be produced. The results obtained exceed the Turkish standard (TS EN 771-1) requirements (9.8–23.54 N/mm2). SEM-EDS results showed that briquette samples made with Tuncbilek (T) fly ash had a higher percentage of the glassy phase than the other briquette samples. Due to this microstructure, it results in higher compressive strength value.

Mechanical Properties and Thermal Conductivity of Aerogel-Incorporated Alkali-Activated Slag Mortars

Compressive strength, thermal conductivity coefficient, and porosimetric properties of alkali-activated slag (AAS) mortars containing silica aerogel were investigated experimentally in this study. For this purpose, slag mortar mixtures at 0.75% and 1.0% aerogel content ratios were prepared, and these mortar mixtures were activated with lithium carbonate (Li2CO3) at 0.03% and 1.50% dosage rates. Mortar samples were exposed to curing process in water for 2, 7, and 28 days, and the samples, which completed the curing stage, were subjected to the compressive strength test. The porosimetry test and the thermal conductivity coefficient measurement were carried out following the compressive strength test on 28-day samples. The varying aerogel content rate in the mixtures and the effects of the dosage of Li2CO3 on the gel, capillary, and macropore distributions, and the effect of changing porosimetric properties on compressive strength and thermal conductivity coefficient were analyzed in detail. Experimental studies have shown that AAS mortars including an optimum 0.75% aerogel content rate and 0.03% Li2CO3 activation provided a compressive strength of 34.1 MPa and a thermal conductivity coefficient of 1.32 W/mK. Aerogel addition provides a partial compressive strength increase at 7- and 28-day samples while it also causes maximum strength loss of 5.0% at 2-day samples.

Analysis of Cement-Based Pastes Mixed with Waste Tire Rubber

Using the methods of thermal gravimetry, differential thermal analysis, Furier transform infrared analysis, and capillary absorption, the properties of a cement composite produced by introducing waste tyre rubber into a cement mixture were investigated. It was found that the composite filled with the rubber had a much lower water absorption ability than the unfilled one.

Assessment of the Material Quality of Damaged Structures after Earthquake in Van, Turkey

AbstractTwo earthquakes occurred on October 23 and November 9, 2011, in Van, Turkey, with magnitudes (Mw) of 7.2 and 5.6, respectively. The types of the damage and collapse that occurred in both earthquakes necessitate a detailed examination of the load-bearing elements, which essentially comprise the components of RC buildings, in terms of their material quality. For this purpose, the compressive strengths, X-ray diffraction (XRD), and scanning electron microscopy with X-ray microanalysis (SEM/EDS) were performed on concrete samples collected from the collapsed buildings, with a view to understand the role of the materials in the devastation caused by the earthquakes. Visual observations and the results of the tests showed that there were not only construction and manufacturing failures, but also the strength of the concrete was a crucial factor that contributed to the damage and collapse of the buildings. In addition to these conclusions, results obtained from XRD and SEM-EDS showed that compressive str...