DETERMINATION OF THE GRAIN DENSITY OF LIGHT-WEIGHT CONCRETE

KORNDICHTEBESTIMMUNG VON LEICHTBETON

VARIOUS METHODS OF DETERMINING BULK GRAIN DENSITY ARE DESCRIBED, AND COMPARED AND DISCUSSED WITH REFERENCE TO TESTS ON EXPANDED SHALE AND CLAY. DEPENDING ON THE TEST METHOD USED, THE DIFFERENCES IN GROSS GRAIN DENSITIES DEPEND ON THE DURATION OF THE TEST, GRAIN SIZE AND WATER ABSORPTION OF THE LIGHT-WEIGHT AGGREGATE. IT IS DEMONSTRATED THAT THERE IS A RELATION BETWEEN THE DENSITY OF A FILL AND THE GROSS GRAIN DENSITY. BY MEANS OF THE GROSS GRAIN DENSITIES DETERMINED, THE NOMINAL GROSS DENSITIES OF LIGHT-WEIGHT CONCRETE ARE TO BE CALCULATED AND COMPARED WITH THE MEASURED DATA. THE DEVIATIONS BETWEEN THE MEASURED AND CALCULATED DATA ARE IN NEARLY ALL TESTS NOT RELATED TO THE MIX DESIGN OF THE LIGHT-WEIGHT CONCRETE MIXTURE BUT ARE DUE TO THE FACT THAT THE WATER ABSORPTION OF THE LIGHT-WEIGHT AGGREGATE DURING CONCRETE PRODUCTION WAS NOT TAKEN INTO ACCOUNT IN THE CALCULATION. FOR THAT REASON, A COMPARISON OF THE METHODS IS NOT POSSIBLE.