PSI - Issue 64

Agostino Walter Bruno et al. / Procedia Structural Integrity 64 (2024) 1411–1418 Bruno et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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3.2. Thermal tests Figure 8 shows the t hermal conductivity (λ) and diffusivity (α), respectively measured in W/(m×K) and in m 2 /s, for all material compositions. Inspection of Figure 8 suggests that all materials are relatively poor thermal insulators as the addition of fibers does not significantly change the original thermal conductivity. Also, there are no significant differences between Nagen and Bouisset samples. The effect of flax fibers is instead evident in terms of thermal diffusivity. Inspection of Figure 8 indicates that, in the case of Nagen earth, the addition of fibers does not significantly change the thermal diffusivity while, in the case of Bouisset earth, the thermal diffusivity clearly increases with growing fiber content, indicating a faster heat transfer through the material.

1.400

1.200

1.000

0.800

0.600

0.400

Thermal Conductivity [W/mK]

0.200

0.000

0.0% FIBERS

0.5% FIBERS

1.0% FIBERS

NAGEN

1.080 1.101

1.121 1.024

1.057 1.045

BOUISSET

0.900

0.800

0.700

0.600

0.500

0.400

0.300

Thermal Diffusivity [mm²/s]

0.200

0.100

0.000

0.0% FIBERS

0.5% FIBERS

1.0% FIBERS

NAGEN

0.591 0.605

0.606 0.698

0.613 0.717

BOUISSET

Fig. 8. Thermal conductivity and diffusivity of unreinforced and reinforced earth samples. The vertical bars represent the range between the minimum and maximum values of strength. 4. Conclusions This study investigated the mechanical and thermal behavior of earth samples reinforced with flax fibers. A comprehensive experimental campaign was conducted to examine various material compositions made of two types of earth (namely a sandy silt and a clayey silt) reinforced with differing flax fiber contents. Test results indicate that