TWO LABORATORY METHODS FOR EVALUATING SKID RESISTANCE PROPERTIES OF AGGREGATES

Abstract

A DESCRIPTION AND EVALUATION OF TWO METHODS ARE GIVEN FOR DETERMINATION OF AGGREGATE SKID-RESISTANCE PROPERTIES IN THE LABORATORY. IN THE FIRST METHOD, PAVEMENT SAMPLES MANUFACTURED FROM THE AGGREGATE TO BE EVALUATED ARE PLACED IN A CIRCULAR TRACK AND SUBJECTED TO WEAR FROM SMALL-DIAMETER PNEUMATIC TIRES. NO ABRASIVE OR WATER IS USED, AND PAVEMENT SPECIMENS CAN USUALLY BE BROUGHT TO TERMINAL POLISH IN ABOUT 16 HOURS. SKID-RESISTANCE VALUES ARE DETERMINED BY USING THE BRITISH PORTABLE TESTER. IN THE SECOND METHOD, COARSE AGGREGATES ARE POLISHED DRY IN A JAR MILL WITH A CHARGE OF FLINT PEBBLES. PAVEMENT SAMPLES ARE MADE FROM THE POLISHED AGGREGATES AND TESTED FOR SKID RESISTANCE BY USING THE BRITISH PORTABLE TESTER. POLISH RATE IS DETERMINED BY EXPOSING A NUMBER OF SAMPLES OF THE SAME AGGREGATE FOR DIFFERENT AMOUNTS OF TIME TO ESTABLISH A WEAR-TIME CURVE. RESULTS FROM THE TWO METHODS ARE DIFFERENT IN VALUE LEVEL BUT SHOW A LINEAR CORRELATION. ALSO, AGGREGATES WERE RATED IN THE SAME ORDER IN BOTH METHODS. TWENTY AGGREGATES WERE USED. /AUTHOR/