The mix-design for low-noise exposed aggregate concrete for roads

Abstract

Concrete wearing surfaces with variations in surface texture have been tested first in Denmark and later throughout EU countries, to study the relationship between surface texture, skid resistance and road noise. Variations in surface aggregates obtained by grinding and brushing or shot blasting, performed to expose such aggregates, were discussed in this study. This was done in order to evaluate an optimum concrete surface texture for today's roads, that should produce minimum tyre noise without compromising skid resistance, while bettering surface drainage conditions. Investigation of noise levels with Exposed Aggregate Concrete pavements are still going on especially in Austria and UK. While in Austria, Belgium and Denmark research is proving that Exposed Aggregate Concrete pavements are formidable contenders for new road pavements and reconstruction, in UK the Highway Agency is reconsidering its outright approval of the 1990's. Thus the controversy of the pros and cons of the Exposed Aggregate Concrete pavement surface are still in process even at the time of writing this dissertation. With Exposed Aggregate Concrete surfaces varying speeds and weights of vehicles, and also road sites, give different noise levels going down as much as 2dB(A) then under normal conditions. The researcher has tested through laboratory work the various types of aggregates available locally in order to see if our hard rock belongs to the High Specification Aggregate required to achieve a Whisper Concrete surface. The results proved negative and unless such aggregates are imported, Whisper Concrete roads are impractical to build in Malta