# Special Issue \"Reinforced Concrete: Materials, Physical Properties and Applications\"
## 10 Assessment on the Properties of Biomass-Aggregate Geopolymer Concrete
Influence of Concrete Strength Class on the Long-Term Static and Dynamic Elastic Modules of Concrete  
Article [12] contributes to filling the gap in information about the concrete strength and its dynamic elastic properties. The dynamic elasticity modulus can be used to evaluate the static elasticity modulus, a key property used during the design phase of a structure, in a non-destructive manner. This article presents the long-term (6 years) laboratory test results of the concrete characteristics in terms of dynamic shear and longitudinal modulus of elasticity, dynamic Poisson's ratio, static modulus of elasticity, compressive and tensile strength in splitting, and their change depending on the strength class of concrete. Experimental Investigations on the Long-Term Material Properties of Rubberized Portland Cement Concrete  
In paper [13], authors present the research work results that aimed at assessing the rubber concrete long-term strength and its elastic properties. The parameters of the study are the rubber substitution of small aggregates and the age of the samples. The concrete cylinders compressive and splitting strength was obtained at the age of 5 years in combination with the static and dynamic elasticity modulus of all concrete samples. In addition, the damping factor of the material is evaluated using non-destructive testing. The density of rubberized concrete decreases with the percentage replacement of natural sand with rubber aggregates. When replacing natural sand with rubber aggregates, the density of concrete decreases. With the age of 5 years, rubberized concrete samples showed a significant drop in density. With an increase in the rubber content in concrete, both static and dynamic moduli of elasticity decrease. The same is true for compressive and tensile strength when splitting. The authors present a very interesting approach to the creation of a new material-rubberized concrete on Portland cement. The durability of such a material plays a crucial role in the creation of new building materials that will allow them to be used in difficult climatic conditions, as well as in difficult operating conditions. Such materials, which are combined, definitely occupy an important niche in modern building materials science and the production of building materials. Influence of Mechanochemical Activation of Concrete Components on the Properties of Vibro-Centrifugated Heavy Concrete  
Article [14] is devoted to the development of a complex technology for the activation effect on concrete produced by various technological methods: vibration, centrifugation and vibro-centrifugation. Chemical water activation and mechanical cement activation are considered. The relevance and prospects of the double complex mechanochemical activation of the components of the concrete mixture are substantiated. In addition, a connection is established between the concrete production technology and its components activation technology. The most optimal manufacturing technology and activation parameters are determined, which result in the greatest increase in the strength characteristics of concrete. An interesting approach to the creation of new variotropic concretes is offered by the authors. At the same time, the authors combine the engineering solution for creating layered structures with a smooth transition of properties along the section with technological solutions, which, in turn, are complex; that is, the authors present the mechanochemical activation of variotropic concretes, which in itself is of great interest and deserves special attention of readers. Influence of Composition and Technological Factors on Variatropic Efficiency and Constructive Quality Coefficients of Lightweight Vibro-Centrifuged Concrete with Alkalized Mixing Water  
Article [15] is devoted to a perspective technology for the manufacture of reinforced concrete structures with low energy, resource and labor intensity based on an improved variotropic configuration of vibro-centrifuged concrete using activated high-pH water.