Volume Deformation and Hydraulic Conductivity Behavior of Sand-Bentonite Mixtures with Fiberglass Additives under High Temperatures

The performance of energy geostructures is dependent on the surrounding soil properties in the presence of high temperatures or thermal cycles. Change in temperature may affect many engineering parameters of soils. Sand-bentonite mixtures or bentonite, which are used as a buffer should keep their performance at design level for a long time. Purpose: In order to improve engineering behavior of soils under high temperatures thermally durable materials may be used. Volume deformation and hydraulic conductivity behavior of 30% bentonite-70% sand mixtures in the presence of fiberglass additives were investigated. Methods: Consolidation tests were performed at room and high temperatures (80 degrees C), hydraulic conductivity tests were started at room temperature, and a temperature cycle (25 degrees C, 50 degrees C, and 80 degrees C) was applied. Results: Fiberglass increased the amount of compression insignificantly under room temperature, whereas the total compression amount increased remarkably under high temperature. On the other hand, the hydraulic conductivity increased under high temperature with fiberglass additive. Conclusions: Fiberglass-added sand-bentonite mixtures can be used around energy structures as an alternative buffer material with high-temperature resistance.