GROUP ANALYSIS TO DETERMINE REPEATED AND COMPARATIVE DISPERSIONS IN THE ESTABLISHMENT OF THE PARTICLE SIZE DISTRIBUTION OF SOILS

RINGANALYSE ZUR ERMITTLUNG VON WIEDERHOL-UND VERGLEICHSSTREUBEREICHEN BEI DER BESTIMMUNG DER KORNVERTEILUNG VON BOEDEN

PARTICLE SIZE DISTRIBUTION IS OF DECISIVE SIGNIFICANCE IN THE EVALUATION OF SOILS WITH RESPECT TO THEIR USE IN ROADS. APART FROM THE MATERIAL REQUIREMENT OF MAINTAINING A DEFINED PARTICLE SIZE DISTRIBUTION IN ORDER TO ACHIEVE THE NECESSARY QUALITY CHARACTERISTICS,THERE ARE LEGAL CONTRACT CONDITIONS WHICH CONTROL THE PROPORTION OF DEFINED PARTICLE SIZES.THUS FOR EXAMPLE THE ZTVE-STB 65 SPECIFICATION DEFINES THE PERMISSIBLE AMOUNT OF CONSTITUENTS WHICH CAN SETTLE IN THE FROST PROTECTION MATERIAL,DIAMETER LESS THAN 0.02 MM.THE GROUP ANALYSIS SHOULD BE CARRIED OUT IN SUCH A WAY THAT GENERALLY VALID STATEMENTS ARE OBTAINED ON THE MAGNITUDE OF THE REPEATED AND COMPARATIVE DISPERSION WHEN PARTICLE SIZE DISTRIBUTIONS ARE DETERMINED FOR ALL AREAS OF ROAD CONSTRUCTION,FOR EARTHWORKS AND FOR UNBOUND AND BOUND ROADBASES.THE RESULTS OF THE PARTICLE SIZE GROUP ANALYSIS SHOULD MAKE IT POSSIBLE TO ASSESS WHETHER DEVIATIONS FROM THE THEORETICAL VALUE OF A FIXED PROPORTION OF PARTICLES LIE WITHIN THE LIMITS OF ERROR WHICH COULD ARISE THROUGH SAMPLING AND TESTING ERRORS.IT IS THEREFORE PLANNED TO CARRY OUT ANALYSES OF PARTICLE SIZE DISTRIBUTION ON THREE TYPES OF SOIL-FROST-PROTECTION GRAVEL (ROUNDED AGGREGATE), SILTY SAND (U LESS THAN 3),AND BROKEN SAND-IN EACH CASE IN 15 LABORATORIES.THE INVESTIGATIONS ARE TO BE CARRIED OUT IN ACCORDANCE WITH IDENTICAL SPECIFICATIONS UNDER CONDITIONS WHICH ARE SIMILAR IN PRACTICE.THREE INDIVIDUAL MEASUREMENTS ARE ANTICIPATED FOR EACH SOIL TYPE AND LABORATORY IN ORDER TO DETERMINE THE REPEATED DISPERSION.THE COMPARISON OF THE RESULTS FROM ALL THE LABORATORIES LEADS TO THE DETERMINATION OF THE COMPARATIVE DISPERSION.THE SAMPLING ERROR IS TO BE DETERMINED SEPARATELY ON TWO TYPES OF SOIL,AND ON THE FROST PROTECTION GRAVEL THE INFLUENCE OF THE PROCEDURE IS ALSO TO BE CONSIDERED BY MEANS OF THE HAAS SETTLEMENT APPARATUS.