An Innovative Absorption Propagation System Hollow Block Made of Concrete Modified with Styrene–Butadiene Rubber and Polyethylene Terephthalate Flakes to Reduce the Propagation of Mechanical Vibrations in Walls

This paper discusses an innovative APS hollow block wall with a frame made of concrete modified with recycled materials. The technical data of the hollow block, the percentages of the recycled materials, including SBR rubber granules and PET flakes in the modified concrete, and the composition of the concrete modified with this mixture of recycled additives, are presented. To demonstrate the effectiveness of the solution in reducing mechanical vibrations, the effect of the interaction of different frequencies of the mechanical wave on reducing these vibrations was evaluated for APS blocks and Alpha comparison blocks. The test was carried out on a developed test stand dedicated to dynamic measurements for sixteen frequencies in the range from 8 to 5000 Hz, forcing a sinusoidal course of vibrations. The results are presented graphically and show that the new type of APS hollow block wall was much more effective in reducing mechanical vibrations. This efficiency was in the range from 10 to 51% for 12 out of the tested 16 frequencies. For the frequencies of 8, 16, 128, and 2000 Hz, the values were obtained with a difference of 3.58% in favor of the APS hollow block. In addition, the study of the damping effectiveness of the APS hollow blocks, in relation to the vibrations generated by an M-400 impact mill, showed that the APS block wall had a higher damping efficiency of 16.87% compared to the Alpha hollow block for the signal reading on the floor next to the mill, and 18.68% for the signal reading on the mill body. The modified concrete used in the production of the APS hollow blocks enabled the effective use of two recycled materials, SBR rubber and polyethylene terephthalate, in the form of PET flakes.