Sound absorbing materials made by embedding crumb rubber waste in a concrete matrix

•Sound absorbing concrete composites with embedded crumb rubber were made.•Various analysis techniques helped to identify the best mixture.•Sound absorbing coefficient α was higher than 0.5 for 9 of 12 samples.•α reached top values of 0.82 and 0.93 when favorable conditions existed.•SOM and PCA techniques were used to identify correlations and similarities.