ABSTRACT
Sound-absorptive barriers contain a porous element that absorbs noise. This porous material can form the surface of the barrier as is the case with concreted woodfibre and granular concrete barriers. Less robust absorptive materials, such as mineral wool, are protected and enclosed within a skin, where the side facing the noise is perforated. These casings are usually made from timber, steel or aluminium sheeting and brick (Figure 5.2).
