Highways Agency Reports

A petrographical examination has been made of the morainic sand fine-aggregate used in Ralumac slurry seal surfacing. It was found to have a complex petrographical composition which, however, can be much simplified as predominantly angular particles of quartz and limestone present in about equal proportions. This composition possibly explains why the sand is an effective fine aggregate - the quartz confers a skid-resistance matrix microtexture, and the limestone provides good adhesion to bituminous binder.