What type of filler do sound-absorbing CMUs use to help reduce sound?

Sound-absorbing concrete masonry units (CMUs) utilize insulating fillers to enhance their acoustic properties. These fillers are designed to trap sound waves and reduce sound transmission through the unit. By incorporating materials that can absorb sound rather than just reflect it, insulating fillers effectively decrease the overall noise levels in a given environment.

Insulating fillers often include materials such as fiberglass or foam, which are specifically engineered to dampen sound and improve the thermal insulation of the units as well. This dual benefit makes them particularly valuable in building constructions where noise reduction is a priority, such as in residential buildings, schools, and offices.

Other types of fillers like granulated, expansive, or organic fillers may not have the specific properties required for sound absorption, making them less effective in this context.