On Innovative Concrete-Rubber Composite Blocks Reducing Effects of Dynamic Mechanical Impact: The Review of Structural Solutions

Abstract

In this paper structural solutions concerning innovative precast concrete hollow blocks with rubber injects are discussed. Knowing that the concrete material has relatively low damping factor, injecting in blocks additional rubber layers improves the overall damping coefficient against propagation of mechanical waves. In order to prepare in the concrete block required hollows under the rubber injects, special form made of plastic or steel is required. Discussed solution is very cheap to achieve. Prepared form could be placed into the cuboid form, where concrete mix has already been poured. After the congeal process both forms could be removed and in the premade hollows, rubber material could be injected. According to that, production process is changed in only a small manner in comparison to the original concrete blocks production. Moreover, as an inject, recycled rubber material may be used. Research conducted by other researchers mainly concerns case, where crumbed rubber is added to the concrete mix in order to obtain desired composite parameters. In this paper different approach is discussed, where rubber is injected into hollow concrete blocks. There were and are performed dynamic and thermal numerical analyses with different shapes or rubber injects. One of the main aims of performed studies is to estimate the damping factor against propagation of mechanical wave in blocks. On the other hand, heat transfer of proposed blocks is also very important from the economical point of view. Despite of analysing single precast concrete-rubber hollow blocks, analyses concerning utilization of that blocks in three-layered wall have also been performed. ADINA code has been used, which is fully based on finite element method. As a concrete material describing hollow blocks C16/20 and C20/25 concrete strength classes have been adopted, which are the most popularly used in Poland. Rubber has been represented via Mooney-Rivlin and/or Zahorski material model. In order to use Zahorski model, special modification of ADINA material library has been introduced. Through the analyses, it has been shown that shape of rubber injects have significant influence on mechanical waves refraction and their dissipation. Moreover, due to relatively small volume of rubber injects in comparison to the whole concrete block, the reduction of block compressive strength would be insignificant. Presented in this paper prototype solutions may be treated as innovative because of rarely met combination of concrete with rubber as well as relatively easy and cheap implementation in the production process.