CATIONIC EMULSIONS FOR SURFACE TREATMENTS

TEST ROADWAYS OF CATIONIC EMULSION CONTAINING HARD ASPHALT AND DO NOT BLEED PROVE SATISFACTORY. CATIONIC ASPHALTIC EMULSIONS ARE PREPARED FROM SELECT PAVING GRADE ASPHALT CEMENTS CAREFULLY MILLED (HOMOGENIZED) WITH A WATER SOLUTION CONTAINING SPECIAL CATIONIC AND ACID TYPE EMULSIFIERS. THE BASIC DIFFERENCE BETWEEN EMULSIFIED ASPHALTS AND CATIONIC EMULSION IS THAT THE CATIONIC HAS BEEN PROCESSED WITH THE COLLOID MILL WHICH BREAKS THE BASE ASPHALT CHARGE INTO MINUTE CHARGED PARTICLES AND DISPERSES THEM INTO THE SOLUTION. THE EMULSION CARRIES A POSITIVE ELECTRICAL CHARGE AND, SINCE MOST MINERAL SURFACES ARE NEGATIVELY CHARGED, THE POLAR ATTRACTION BETWEEN THE CATIONIC EMULSION AND THE ANIONIC AGGREGATE GIVES SUPERIOR ADHESION OF THE ASPHALT AND AGGREGATE SYSTEM. FIELD PERFORMANCE SHOWS THAT CATIONIC EMULSIONS PERFORM EQUALLY WELL WITH CARBONATE AND SILICEOUS AGGREGATES. TWO THEORIES FOR THIS COMPATABILITY ARE: (1) DUE TO THE HIGH KINETIC ENERGY VIBRATION OF THE CATIONIC EMULSIFIERS, THEY HAVE A NATURAL AFFINITY FOR ALL SOLID SURFACES, AND (2) FREE ACIDS ATTACK THE SURFACE OF THE BASIS STONE AND INSOLUBLE REACTION FORMED AT THE BITUMEN-AGGREGATE INTERFACE PROMOTES FIRM ADHESION. ADVANTAGES OF THE USE OF CATIONIC EMULSION SURFACE TREATMENTS ARE: (1) THE HARD ASPHALT OF 85-100 AND 150-200 PENETRATION ELIMINATES BLEEDING, (2) AMBIENT TEMPERATURE, THOUGH IMPORTANT, IS NOT AS CRITICAL AS FOR NORMAL SURFACE TREATMENTS, (3) THOUGH SURFACING IN THE RAIN IS NOT ADVISED, SUCCESSFUL PAVEMENTS WERE OBTAINED WHEN SURFACING OPERATIONS WERE CONTINUED UNINTERRUPTED DURING PERIODS OF PRECIPITATION, (4) A DAMP ROADWAY WITH NO FREE WATER AND WET AGGREGATE IS DESIRED FOR BEST RESULTS, (5) THE CATIONIC MATERIAL IS EXTREMELY FLUID AND FLOWS INTO CRACKS AND VOIDS, THEREBY PROVIDING A MORE WATERPROOF SEAL, AND (6) APPLICATION TEMPERATURES ARE KEPT BETWEEN 110 AND 160F MAKING THE OPERATION SAFER THAN WITH THE CONVENTIONAL ASPHALTS. DISADVANTAGES TO THE USE OF CATIONIC EMULSIONS ARE: (1) TRAFFIC MUST BE RIGIDLY CONTROLLED UNTIL THE MATERIAL BREAKS FOR BEST RESULTS, (2) NO FURTHER AGGREGATE EMBEDMENT WILL TAKE PLACE AFTER THE EMULSION BREAKS, AND (3) DISTRIBUTORS OR CONTAINERS MUST BE FREE OF ALL OTHER TYPES OF ASPHALTIC MATERIALS PRIOR TO FILLING WITH CATIONIC EMULSIONS. CHARACTERISTICS AND PROBLEMS IN USING CATIONIC EMULSIONS ARE DISCUSSED.

• Supplemental Notes:
  • pp 114-123, 3 REF
• Corporate Authors:

  Sixth Paving Conference Proc

  ,    
• Authors:
  • Hoss, N P
• Publication Date: 1968

Subject/Index Terms

• TRT Terms: Adhesion; Aggregates; Anions; Asphalt cement; Bleeding; Cationic emulsified asphalt; Experimental roads; Kinetic energy; Performance; Surface treating; Work zone traffic control
• Uncontrolled Terms: Field performance
• Subject Areas: Geotechnology; Highways; Maintenance and Preservation; Materials;

Filing Info

• Accession Number: 00218553
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 2 1970 12:00AM