MOVEMENTS OF JOINTS IN CONCRETE ROADS AND THEIR RELATION TO TEMPERATURE WITH VARIABLE SURFACE CONDITION OF THE BASE

FUGENBEWEGUNGEN BEI BETONFAHRBAHNEN UND IHRE ABHAENGIGKEIT VON DER TEMPERATUR BEI UNTERSCHIEDLICHER OBERFLAECHENBESCHAFFENHEIT DER UNTERLAGE

SEVERAL EXPERIMENTAL SECTIONS ON A CEMENT-BOUND BASE AND AN EXPERIMENTAL SECTION ON A BITUMEN-BOUND BASE WERE INCORPORATED INTO THE WUERZBURG-WEINSBERG MOTORWAY BETWEEN WIDDERN AND WEINSBERG. MEASUREMENTS OF TEMPERATURES AND JOINT OPENINGS LASTED DIFFERENT LENGTHS OF TIME FOR THE INDIVIDUAL EXPERIMENTAL SECTIONS. BASED ON THE CALCULATED SCATTER OF RECORDED LONGITUDINAL PROFILES, IT WAS PROVED THAT THE SURFACE STRUCTURE OF THE CEMENT STABILISED BASE CAN BE DIVIDED INTO FIVE CLASSES FROM "SMOOTH" TO "VERY ROUGH". THE EFFECT OF THE BASE OF THE CONCRETE SURFACING ON EARLY AND UNIFORM CRACKING OF CONTRACTION JOINTS CAN BE CLEARLY ESTABLISHED. ON THE CEMENT-STABILISED BASE THE CONTRACTION JOINTS IN THE EXPERIMENTAL SECTIONS OPENED WITHIN THE FIRST THREE DAYS, INDEPENDENTLY OF THE SURFACE CONDITION OF THE BASE. WITH THE BITUMINOUS LAYER TYPICAL BUNDLES OF CRACKS ASSOCIATED WITH LARGE ADDITIONAL OPENING OF THE JOINTS OCCURRED.