Influence of temperature and fiber content on direct shear properties of plain ice and fiber-reinforced ice

Abstract

As a new kind of building material, ice has been paid more and more attention and applied in cold, polar regions and the outer space. The shear mechanical properties of plain ice and fiber-reinforced ice (FRI) were studied by a modified direct shear test. Five types of FRI containing 0%, 1%, 2%, 4% and 6% fiber content of bleached sulfate softwood pulp (BSSP) fiber were prepared and tested under −20, −15, −10 and − 5 °C. The results showed that the brittle failure of plain ice was in contrast to the ductility of FRI. With the decrease of temperature, the shear strength and peak deformation increased. The shear strength and deformation of ice at −20 °C were 2–2.5 times and 1.1–1.4 times higher than those at −5 °C. The study also showed that with the increasing fiber content, the shear strength and peak deformation increased. The shear strength and peak deformation of FRI with 6% fiber content were 3.8–5.9 times and 2–3times higher than those of plain ice. Equations predicting the shear strength and peak deformation of ice considering the temperature and fiber content were proposed, and the relationship between shear strength and compressive strength was investigated. Through the analysis of shear ductility coefficient, the increase of fiber content and decrease of temperature greatly improved the energy absorption capacity and subsequent bearing capacity of ice in the shear process. A shear constitutive model was proposed to predict the relationship between shear strength and deformation.