MODIFIERS FOR ASPHALT CONCRETE

HIGH TIRE PRESSURE AND THRUST VECTORING ON ASPHALT CONCRETE AIRFIELD RUNWAYS ARE DETRIMENTAL FACTORS TO SERVICEABILITY PERFORMANCE CHARACTERISTICS OF THESE SURFACES. RUTTING, RAVELING AND CRACKING ARE SOME DISTRESS MANIFESTATIONS BY WHICH RUNWAY PAVEMENTS WILL DETERIORATE. HOWEVER, NEW AND INNOVATIVE MATERIALS--ADDITIVES/ ADMIXTURES, EXTENDERS, OR ALTERNATE BINDERS--WITH THE POTENTIAL TO SOLVE THE PROBLEMS HAVE BEEN INTRODUCED TO THE MARKET. SOME MATERIALS HAVE BEEN LABORATORY AND FIELD TRIED ON A LIMITED BASIS, BUT FOR DIFFERENT APPLICATIONS AND UNDER LESS SEVERE LOADING CONDITIONS THAN THAT ANTICIPATED ON THE AIRFIELD PAVEMENT. THERE IS A NEED TO INVESTIGATE THESE MATERIALS FOR THIS SPECIFIC APPLICATION AND TO CONSIDER SUCH FACTORS AS THE SCREENING CRITERIA (COMPATIBILITY WITH ASPHALT CEMENT, POTENTIAL CANDIDACY TO SOLVE THE PROBLEMS, AND COST PROHIBITIVE FACTORS), MIX DESIGN SPECIFICATION AND QUALITY/CONTROL TESTING, AS WELL AS COST EFFECTIVENESS PROCEDURES. PHASE I OF THIS RESEARCH IS CONCERNED WITH DEVELOPMENT OF THE SCREENING CRITERIA AND DESIGN OF EXPERIMENT FOR PHASE II; PHASE II WILL ADDRESS LABORATORY/ FIELD CHARACTERISTICS, DEVELOPMENT OF Q/C TESTS AND SPECIFICATIONS (MIXTURE, SPECIAL PROVISION FOR CONSTRUCTION), AND THE EVALUATION OF COST EFFECTIVENESS.