ACOUSTIC ISOLATION OF STRUCTURAL WALLS WITH FILLED AND UNFILLED MORTAR HEAD JOINTS

摘要

New technologies are used in the civil construction, but many of them have not been tested properly before its application. Construction of structural walls without filling in the head (vertical) joints is an example of this reality. The following arguments have supported the technology: increase of productivity, improvement of water resistance and acoustic isolation. The bibliographical research confirmed that the non-filling of the head joints really increased productivity and improved water resistance, but, on the other hand, it reduced shear strength. As to the acoustic characteristics, the bibliographical analysis has not given a sufficient basis to illuminate some doubts and to arrive at a conclusion. Measurements of the sound isolation were earned out on the walls constructed of structural hollow clay blocks with the objective to compare the acoustic behavior of walls with filled and unfilled mortar head joints. The measurements were carried out according to the norm ISO 140. The following results were obtained: for the walls with unfilled head joints and coating on the both sides the loss of sound transmission (PT) was 43,4 dB(A) while for the same walls, but with filled head joints, PT = 48,4 dB(A). The difference in the sound isolation to the aerial noise was equal to 5 dB(A) between the two technologies. The results demonstrated that filled mortar head joints almost triplicate the acoustic performance of walls.