Bor katkılarının kum-bentonit karışımlarının yüksek ısılar varlığında permeabilite ve kayma dayanımı davranışı üzerindeki etkilerinin araştırılması

The importance of thermal behavior of soils has increased considerably in last decades. High thermal resistance and durable soils are needed for structures such as; nuclear waste disposal facilities, buried high voltage cables, energy piles etc. These structures cause thermal variations in the surrounding soils. The soil engineering properties are temperature dependent. For that reason, the change in engineering properties of soils should be investigated under high temperatures and thermal cycles. Sand-bentonite mixtures are usually used for impervious barriers at nuclear waste repositories, municipal solid waste landfill liners, etc. These mixtures must keep their strength and hydraulic conductivity properties without any changes for a very long time. The literature studies have shown that high temperature and thermal cycles have negative effects on the hydraulic conductivity and shear strength of soils. For that reason, the resistivity of sand-bentonite mixtures should be increased against high temperatures when they are used in liners. Boron reduces heat expansion of the glasses, protects the glass against acid and scratches. Boron minerals are used in order to increase the thermal resistivity of materials in industry. Hence the boron minerals can be added to the sand-bentonite mixtures in order to improve strength and hydraulic conductivity properties of these mixtures against high temperature or thermal cycles. In this study, compaction, shear strength and hydraulic conductivity properties of sand-bentonite mixtures were determined in the presence of boron mineral; namely colemanite, tincal and ulexite. The sand-bentonite mixtures were prepared with 10 and 20 percentage bentonite and boron minerals were added to these mixtures. The direct shear and the hydraulic conductivity tests were conducted under 80 Celsius degrees and room temperature.