Study of mechanical properties of cellulose reinforced ice
No Thumbnail Available
Insinööritieteiden korkeakoulu | Master's thesis
Ask about the availability of the thesis by sending email to the Aalto University Learning Centre firstname.lastname@example.org
Master's Programme in Structural Engineering and Building Technology
AbstractIn arctic region, ice has been used as a building material for a long time. However, the strength of ice is not high enough to be used in structures where higher stresses occur. Besides this, due to high homologous temperature, creep is a dominating mechanical characteristic of ice. Therefore, strengthening of ice is necessary to build structures to stand higher stresses. The mechanical strength of ice can be improved by reinforcing it with some materials such as sawdust, wood pulp, cellulose, geo-grid, fibreglass and so on. In this thesis, mechanical properties of cellulose reinforced ice composites are examined thoroughly, and compared with the properties of pure ice. The mechanical properties included compressive strength, modulus of elasticity and creep behaviour. The newly developed ice composite has been named as 'cellcrete'. The experimental study included compression tests at three different strain rates and creep tests at two stress levels. Besides this, to find the optimal water to cellulose ratio, different mass fractions of cellulose were tried out. The temperature was, -10 ⁰C in both compression and creep tests. Preparation of specimens with given properties was also part of the study, specially for pure ice specimens. The whole experimental setup was constructed from the scratch and hence, pure ice specimens were tested as a reference. In the experiments, the accuracy was maintained as carefully as possible. The test results show that, adding cellulose in ice specimens improved the compressive strength and modulus of elasticity of ice composite compared to pure ice. The creep behaviour of cellcrete was also better compared to pure ice. Depending on strain rate (10-4 s-1 < ε ̇ < 10-2 s-1) the compressive strength of cellcrete varies from 4 to 12 MPa. Whereas, at the same strain rates, compressive strength of pure ice varies from 6 to 10 MPa. It can also be noticed that, cellcrete of various concentrations have 10 to 12 times lower creep rate than pure ice. Another observation was that, cellcrete specimens were more ductile compared to pure ice. Besides this, cellulose-ice composite has a natural white colour which would make structures look aesthetically better compared to other ice composites such as pykrete.
Thesis advisorSalokangas, Lauri
cellcrete, cellulose, pure ice, creep rate, compressive strength, ductility