*3.2. Results of Deformation, Young's Modulus, and Poisson's Coefficient Tests*

#### 3.2.1. Stress–Strain Dependencies

The results of measurements of the dependence of the deformation of the tested samples in the longitudinal and transverse directions to the applied load are shown in Figure 8.

In each of the analyzed cases, the range of compressive strains of the tested samples exceeds the tensile strain values. With the increase in the value of the angle θ of the tested samples, the value of tensile strain (in the direction transverse to the direction of the force) increases. The range of compressive stresses in the area of elastic work of the wall also changes due to the different strength of the tested samples, loaded at different angles θ.

**Figure 8.** Stress–strain diagrams for compressed wall samples at different joint angles (**a**) θ = 0◦, (**b**) θ = 22.5◦, (**c**) θ = 45◦, (**d**) θ = 67.5◦, (**e**) θ = 90◦.

#### 3.2.2. Young Modulus Measurements

The results obtained during the Young's modulus measurements are presented in Table 3.


**Table 3.** Young's modulus test results of wall samples with different angle of bed joints θ.

The highest value of the modulus of elasticity (*E* = 11.146 GPa) was obtained for samples loaded perpendicularly to horizontal joints (θ = 0◦). The lowest value of *E* = 8.563 GPa was obtained for the samples with angle θ = 67.5◦. Figure 9 presents the changes in the Young's modulus of the wall in relation to the reference model (samples θ = 0◦) in dependence of the bed joints angle θ.

The lowest value of the coefficient *E*θ/*E*<sup>0</sup> has been obtained for samples with joints rotated at an angle θ = 67.5◦.

**Figure 9.** Changes in Young's modulus coefficient *E*θ/*E*<sup>0</sup> in regard to the angle of the head joints angle θ.

#### 3.2.3. Measurements of the Poisson's ratio

The results of the Poisson's coefficient measurements are presented in Table 4.

**Table 4.** Poisson's ratio testing results of wall samples with different angles of bed joints θ.


The lowest value of the Poisson coefficient *νxy* = 0.156 was obtained for samples with a load acting perpendicularly to the bed joints. The highest value *νxy* = 0.290 was acquired with the samples rotated with angle θ = 22.5◦. Figure 10 presents the graph with an approximate dependence between coefficient *ν*θ/*ν*<sup>0</sup> and the load acting on samples with bed joints rotated with angle θ.

**Figure 10.** Changes in Poisson's ratio *ν*θ/*ν*<sup>0</sup> in regard to the angle of the bed joints θ.

The maximum value has been obtained with angle θ = 67.5◦, with coefficient *ν*θ/*ν*<sup>0</sup> = 1.81. Figure 11 presents the representative Poisson's ratio–stress curves of tested wall panels at different angles θ.

The difference in the course of the curves is visible both in the value of the Poisson number after their stabilization from the initial stresses and in the range of their subsequent increases.

For the angle θ = 0◦, the course of the curve (after stabilization in the range of the initial stress increase) is characterized by a slight upward trend from *νxy* = 0.10 to 0.15 at the end of the measuring range reaching 40–50% of the limit stress. Samples with bed joints turned by the angle θ = 22.5◦ are characterized by a parallel course of the dependence *νxy*-*σ* in the range up to 40–60% of the maximum stresses. Then the value of the Poisson number increases with the increase in deformation of the samples in the horizontal direction and the formation of vertical cracks. Along with increasing the value of the angle θ to a value of 67.5◦, the value of the Poisson's ratio increases. For the angle of θ = 45◦, it reaches the value of 0.2 with a load equal to 15% of the limit value and 0.25 with 30% of the maximum stress. This increase is related to the formation of the first cracks. As stress increases further, the Poisson ratio also increases. Strain values in the horizontal direction become equal to the vertical direction at stresses equal to half of the limit values. In the case of the tested panels θ = 67.5◦, the initial value of the Poisson's ratio is characterized by the highest value among all the tested wall models (*νxy* = 0.29) up to the value of 30% of the ultimate stresses. Above 30% of stresses, the value of *νxy* increases. In the tested range of deformations, the Poisson's number reaches a value of 0.8 at stresses equal to 40% of the limit value. For θ = 90◦, in the range from 5 to 30% of the ultimate stress, the value of *νxy* was within the range of 0.22 to 0.25. Above the value of 25–30% of the limit stress, the Poisson number increases, reaching a value of 0.37 at 40% of the limit stress.

**Figure 11.** Representative Poisson's ratio–stress curves of tested wall panels at different joint angles (**a**) θ = 0◦, (**b**) θ = 22.5◦, (**c**) θ = 45◦, (**d**) θ = 67.5◦, (**e**) θ = 90◦.
