Developing non-destructive methods (NDT) that can deliver faster and more accurate results is an objective pursued by many researchers. The purpose of this paper is to present a new approach in predicting the concrete compressive strength through means of ultrasonic testing for non-destructive determination of the dynamic and static modulus of elasticity. For this study, the dynamic Poisson’s coefficient was assigned values provided by technical literature. Using ultra-sonic pulse velocity (UPV) the apparent density and the dynamic modulus of elasticity were determined. The viability of the theoretical approach proposed by Salman, used for the air-dry density determination (predicted density), was experimentally confirmed (measured density). The calculated accuracy of the Salman method ranged between 98 and 99% for all the four groups of specimens used in the study. Furthermore, the static modulus of elasticity was deducted through a linear relationship between the two moduli of elasticity. Finally, the concrete compressive strength was mathematically determined by using the previously mentioned parameters. The accuracy of the proposed method for concrete compressive strength assessment ranged between 92 and 94%. The precision was established with respect to the destructive testing of concrete cores. For this research, the experimental part was performed on concrete cores extracted from different elements of different structures and divided into four distinct groups. The high rate of accuracy in predicting the concrete compressive strength, provided by this study, exceeds 90% with respect to the reference, and makes this method suitable for further investigations related to both the optimization of the procedure and = the domain of applicability (in terms of structural aspects and concrete mix design, environmental conditions, etc.).

The present paper presents some of the results of the experimental research carried out by the authors in order to obtain construction materials, mortars in particular, which are more environmentally friendly, less polluting, while aiming to obtain new materials that also help to increase the energy efficiency of buildings. The study includes the realization and testing of several mortar samples with different compositions in order to reduce the consumption of cement, a polluting material by its way of obtaining but a main component of mortars. The mortar samples had cement and perlite in different dosages and some of them also had lime in different quantities. They have been mechanically tested, determining bending tensile strengths and compressive strengths. At the same time, there are some physical characteristics for the mortars obtained, namely the density of the samples and their mass loss over time. The interpretation of the results obtained helps us to obtain useful information regarding the composition of mortars with the addition of perlite, an ecological material, difficult to degrade, with special physical properties and the possibilities of their use in constructions in order to increase the energy efficiency of buildings, reduce energy consumption and in identifying new efficient and sustainable solutions for constructions and for the built environment.

The assessment of compressive strength, and air-dry density constitutes essential parameters for evaluating the quality and performance of earthen construction materials. To ascertain these properties, this study investigates the potential application of ultrasonic testing as a non-destructive evaluation technique for earthen materials, including specimens, elements, or structures. The methodology is predicated on the measurement of ultrasonic pulse velocity (UPV), which is affected by various factors such as density, elasticity, and the curing process. By examining the propagation of ultrasonic waves through earthen samples, significant insights can be obtained regarding their drying duration, compressive strength, and density. Compressive strength is a pivotal factor in evaluating the structural integrity of earthen materials. The UPV method provides a non-destructive means to ascertain the compressive strength of earthen samples, thereby serving as a valuable instrument for quality control and assessment of earthen construction materials. Density, another critical property influencing the performance of earthen materials, can also be evaluated using the UPV method. By measuring ultrasonic pulse velocity and analyzing its correlation with density, this non-destructive approach enables rapid and efficient estimation of the compactness and quality of earthen mixtures. The ultrasonic method presents a non-destructive and efficient strategy for determining the compressive strength, and density of various soil compositions. By quantifying pulse velocity and examining its relationship with these properties, substantial insights can be garnered regarding the quality and performance of earthen construction materials. This technique holds the potential to enhance assessment and quality control processes in earthen construction, ultimately contributing to the development of more sustainable and reliable structures utilizing earthen techniques.