SAND-BITUMINOUS STABILIZATION

IN ORDER TO OBTAIN A LOW COST, YEAR-ROUND PAVEMENT IN SPARSELY POPULATED SECTION OF FLORIDA WHERE EXISTING ROAD MATERIAL WAS IMPASSABLE SAND OR SILTY SAND, THE FLORIDA STATE ROAD DEPARTMENT BEGAN STABILIZING THESE SANDY MATERIALS WITH BITUMINOUS MATERIAL. STABILIZATION OF SANDY SOIL HAS BEEN ACCOMPLISHED BY THE ADDITION OF BITUMINOUS MATERIAL, IN PROPER QUANTITY, TO EXISTING ROAD MATERIAL. THIS IS MIXED UNIFORMLY IN PLACE WITH HARROWS AND GRADERS OR A TRAVELING PLANT MIXER, AND THEN COMPACTED WITH ROLLERS. STABILITY TESTS ON THE SAND ARE MADE PRIOR TO ADDITION OF BITUMINOUS MATERIAL, AND IF NECESSARY THE STABILITY IS INCREASED BY THE ADDITION OF OTHER FINE AGGREGATE, PULVERIZED LIME-STONE OR SIMILAR MATERIAL HAVING GREATER STABILITY. THE BITUMINOUS MATERIAL USED HAS BEEN CUT-BACK ASPHALT AND TAR. THE RESULTS OBTAINED HAVE BEEN ENTIRELY SATISFACTORY. ABOUT 314 MILES OF THIS TYPE OF ROAD ARE CARRYING TRAFFIC WITH A VERY LOW MAINTENANCE COST. WHEN THE SURFACES BEGAN TO SHOW SIGNS OF WEAR THEY WERE CONVERTED INTO BASES BY APPLICATION SURFACE TREATMENTS. IN SOME CASES THE SURFACE TREATMENTS HAVE BEEN NECESSARY IN ABOUT TWO YEARS, WHILE OTHER PAVEMENTS HAVE GONE SEVEN YEARS AND ARE STILL HOLDING UP. THE NECESSITY FOR TREATMENT DEPENDS ON THE TYPE OF BITUMINOUS MATERIAL USED AND THE AMOUNT OF TRAFFIC. /AUTHOR/