The aim of this study was to test the isotropic behavior hypothesis for concrete by means of wave propagation tests. The elastic properties of the concrete were determined using ultrasound tests with 1.0 MHz longitudinal and transversal transducers in polyhedral specimens with 26 faces. The concrete was analyzed using the theoretical aspects of three types of elastic behavior, namely isotropy, transverse isotropy, and orthotropy, in concretes with different compressive strengths and coarse aggregate size distributions. The results show that there were no statistically significant differences in the elastic parameters on the three symmetry axes. The constitutive relation between the shear modulus and longitudinal modulus, which involves Poisson’s ratio, was as expected for isotropic materials, and the elastic properties of the concrete differed equally as a function of the compressive strength. Considering the results, the isotropic behavior of the concrete was validated regardless of the elastic behavior adopted in the analyses.

The use of nondestructive techniques in the technological control of concrete allows to evaluate and monitor the condition of the material without interfering with its properties; therefore, it is highly desirable in on-site inspections. Among these techniques, ultrasonic testing stands out as one of the most promising by its speed and simplicity to obtain results. However, inferences of strength and stiffness properties using ultrasound parameters should be made with caution, since many factors may interfere with wave propagation. This research aimed to evaluate the behavior of parameters obtained by ultrasonic testing (velocity of wave propagation [V] and stiffness coefficient [C = density × V²]) as predictors of the strength (f_c) and stiffness (E_ci) of concrete produced with coarse aggregates from different mineralogical origins. To achieve the objective, 128 specimens were produced with four aggregate mineralogical origins and four water-cement ratios, with 8 replications each. The ultrasonic tests were performed with two-frequency transducers (45 and 80 kHz). Prediction models of f_c and E_ci were statistically significant (P-value < 0,05) for both frequencies. The model using [C] as independent variable present better correlation with E_ci (R² > 91,2%) and with f_c (R² > 82%) than the model using only [V]. General regression models (regardless of the gravel type) were also statistically significant (P-value < 0.05), with R² > 79% and prediction errors higher than those obtained for the specific models for different rock types.

The complete characterization of wood, with the determination of the 12 elastic constants that represent its orthotropy, is greatly relevant in applications employing structural calculation software programs. Ultrasound allows for such characterization with relative simplicity when compared to other methods. The polyhedron is considered the most appropriate specimen format for allowing the 12 constants to be calculated with a single specimen, and the traditionally used one is the 26-sided polyhedron, which, to be produced manually with more precision in directing the main directions of the wood, needs larger faces. The accuracy of this technique tends to be reduced when increasing the growth rings’ inclination since the waves deviate from the main directions of orthotropy. This research aimed to verify whether it is possible to reduce the polyhedra dimension without affecting the results of the elastic parameters obtained in wood characterization by ultrasound. The results indicate that the dimension of the polyhedron can be reduced without prejudice to the results of the elastic parameters obtained by the ultrasound test and that, in the manual production process of the specimen, the best way to make this reduction is to eliminate the faces unused in the test, changing the polyhedron to 18 faces instead of 26. Reducing the number of faces simplifies the manufacturing process and thus increases the possibility of producing specimens with straighter growth rings and better-directed symmetry axes.

The diversity of commercial tree planting sites, with their distinct environmental conditions, directly influences tree growth and consequently impacts the wood properties in various ways. However, there is limited research evaluating the impact of these variations in nondestructive testing. Therefore, this study aimed to investigate whether edaphoclimatic variations affect parameters obtained through nondestructive tests conducted on standing trees. To this end, 30 specimens were selected from 3 Eucalyptus sp. clones, aged 1, 3, and 4 years, grown in 2 regions, totaling 540 trees. Tree development was monitored quarterly over 12 months. The tests included ultrasound propagation, drilling resistance, and penetration resistance, and the trees were measured for diameter at breast height (DBH) and height. Among the edaphoclimatic factors evaluated, only temperature and soil water storage differed statistically between the two study regions. The higher temperature and lower soil water storage in region 2 promoted tree growth, with these trees showing greater drilling resistance and higher longitudinal wave velocities. In addition, the influence of climatic factors was evidenced by the variation of wave propagation velocity throughout the year. Periods of lower water availability resulted in higher velocities, while periods of greater precipitation were associated with lower velocities. The research results showed that temperature and soil water storage had significant effects on tree growth (DBH and height), as well as ultrasound wave propagation velocity and drilling resistance.