Porous concrete as non-sand concrete with silica fume substitution for the application of sound absorbing materials in buildings

Sound-absorbing acoustic materials are usually made of special materials which are sometimes expensive and prone to fire and do not have sufficient strength. This research offers materials that have sufficient properties for the above problems, namely by using porous concrete. This study aims to calculate the absorption values of porous concrete values. Porous concrete is concrete which does not use sand to forms a void in concrete that also might be used as a sound absorbent. The concrete then is substituted with silica fume to reach more compressive strength. The value of absorption was measured by the impedance method of two microphones. The sample was put in a tube with a diameter of 10 cm and a height of 5 cm. The proportion of samples using American NRMCA. Tests were carried out in the frequency range of 0-1600 Hz. The best sample is a sample with a 25 void ratio that could absorb sound over a long frequency range of 432-1600 Hz even though it only reaches class B. While the highest value of absorption coefficients was the sample with a void ratio of 20 which reach a value of 0.99997. The highest stiffness was achieved by 5 void concrete with a value of k= 5.8×106. © 2020 Trans Tech Publications Ltd, Switzerland.