SUPPLEMENTARY STUDIES ON THE INFLUENCE OF THE SAND COMPONENTS ON THE PROPERTIES OF BITUMINOUS MORTARS

ERGAENZENDE UNTERSUCHUNGEN UEBER DEN EINFLUSS DER SANDKOMPONENTE AUF DIE EIGENSCHAFTEN BITUMINOESER MOERTEL

IN THE STUDIES CARRIED OUT HITHERTO AS PART OF RESEARCH PROJECT FA 9.101 (IRRD NO. 039041), THE MAIN CONSIDERATION WAS THE WEAR STRENGTH OF THE BITUMINOUS MORTAR IN RELATION TO THE SAND QUALITY, AND PURE MATERIAL PROPERTIES OF THE SANDS WERE NOT EXTRAPOLATED. AN ATTEMPT IS TO BE MADE TO CONSIDER THE PURE MATERIAL PROPERTIES OF THE SANDS AND THEIR EFFECT ON THE WEAR STRENGTH OF THE BITUMINOUS MORTAR, BUT ALSO IN RESPECT TO THE COMPACTIBILITY AND STABILITY OF THE MORTAR. IT IS INTENDED TO TAKE AT LEAST 20 SANDS FROM VARIOUS QUARRIES AND SAND DEPOSITS AND TO SUPPLEMENT PREVIOUS FREQUENCY DISTRIBUTIONS FOR VIBRATION AND/OR IMPACT ABRASION VALUES. FOLLOWING THIS, PARTICULAR MATERIAL PROPERTIES OF THE CHARACTERISTIC CRUSHED STONE AND NATURAL SANDS STUDIED PREVIOUSLY ARE TO BE EXAMINED FOR THEIR EFFECT ON COMPACTIBILITY, STABILITY AND WEARING STRENGTH OF THE BITUMINOUS MORTAR. THESE PROPERTIES ARE: PARTICLE COMPOSITION OF THE SANDS; PARTICLE SHAPE (BY MEANS OF SLOTTED SIEVES); PARTICLE STRENGTH (IMPACT AND IMPACT ABRASION TESTS); RESISTANCE TO WEATHERING (FREEZING-THAWING TESTS DIN 4226, CRYSTALLIZATION TESTS DIN 52111); PROPERTIES OF THE FINEST PARTICLES. THE STUDIES OF WEAR STRENGTH ARE TO BE SUPPLEMENTED BY IMPACT ABRASION TESTS ON "OPEN" (AS HITHERTO) AND "DENSE" SAND ASPHALT OR ASPHALTIC CONCRETE SAMPLES. THE QUESTION OF THE GRADING OF SANDS IN DENSE MIXTURES ALSO HAS TO BE DEALT WITH. THE RESULTS WILL SERVE AS A BASIS FOR DISCUSSION IN THE WORKING GROUP ON "SAND QUALITY" OF FG DURING THE DRAWING UP OF CRITERIA FOR EVALUATING CRUSHED STONE AND NATURAL SANDS.