Şişen Killerin Stabilizasyonunda Katkı Malzemesi Olarak Atık Cam Kullanımı

Abstract

The increase in volume, known as ‘swelling’, developing as a result of increase in the water content of clayey soils, which are generally located in arid climates, causes various engineering problems. In order to minimize deformations, which are developed in engineering structures due to the swelling characteristics of clays in soils, it is very important to examine the swelling behaviour of the soils and improve their mechanical properties. Additive stabilization is an advantageous method, which saves a lot in the cost and application process, for improving the engineering properties of swelling clays. The aim of this method is to improve the physical and mechanical parameters of the soil by forming a chemical reaction by mixing different additives to the soil. By the application of additive stabilization technique, water content and void ratio of the soil are regulated and intergranular bonding is increased. Although many studies have been done to stabilize clayey soils, the number of studies using waste glass as an additive in the stabilization process is limited. It is observed that the performance of the stabilization process under natural conditions is not evaluated in the literature. Within the scope of the thesis, the use of waste glass in stabilization of Ankara Clay which has high swelling potential was investigated. A certain proportions of waste glass powder were added to the Ankara Clay and the change in uniaxial compressive strength and free swelling index iv were determined. The effect of waste glass powder on shear strength parameters of the soil was also evaluated. Stabilized samples were subjected to wetting-drying and freezing-thawing cycles and the amount of change in their strength under natural conditions was predicted. The mineralogical changes of soil samples after stabilization process were investigated by XRD method. Microstructural analysis studies were performed by using SEM technique. In this study, it has been observed that when waste glass was used alone, its effects were limited. It has been observed that the success of the stabilization process can be increased if the activity of the glass powder is provided with the alkali materials. More efficient results were obtained in the experiments using CaOactivated waste glass powder as a stabilizing material. 15% glass powder and 5% CaO added samples were determined to have a 291% increase in uniaxial compressive strength at the end of 14 days of curing period. It was determined that in samples that were prepared with CaO in addition to the glass powder, the free swelling index decreased by 72.7%. At the end of the wetting-drying and freezing-thawing cycles, when the strength of the samples were evaluated among themself, the most effective additive type was found to be 15% glass powder + 5% CaO. At the end of 2 wetting-drying cycles, the uniaxial compressive strength of the soil, which was stabilized with 15% glass powder and 5% CaO, was determined as 2052.4 kPa. After wetting-drying cycles, a decrease in the strength of the sample is expected. In this case, however, an increase of 179.6% in the strength of the sample was determined. At the end of 3 freezing-thawing cycles, the highest strength value was obtained 15% glass powder + 5% CaO added sample with 548.7 kPa. Keywords: Ankara Clay, Swelling, Waste glass, Stabilization, Wetting-drying, Freezingthawing.