Estimation of Appropriate Filler Quantity in Asphalt Mix from Microscopic Studies

Abstract

The type and quantity of filler influences the property of the asphalt mix. The filler quantity, similar to fine and coarser aggregates, is typically specified in proportions of weight. If the specific gravity of the filler is significantly different than the rest of the aggregates (for example, alternative fillers derived from industrial and domestic wastes), weight proportioning may lead to undesirably low or high quantity of filler in the mix. To investigate this issue further, in the present work filler concentration (in terms of percentage area occupancy) is studied at the microscopic level with the help of a scanning electron microscope. Three different types of fillers are chosen and are separately added to asphalt mix in varying proportions. The indirect tensile strength values and the corresponding filler concentration levels of these samples are noted. From limited data gathered in the present study, it appears that the average filler concentration values corresponding to the maximum indirect tensile strength levels for the mixes are statistically same. That means, even though optimum filler quantities (by weight) are different for these three mixes, the filler concentration values are almost the same. Subsequently, design chart is suggested to estimate the optimum quantity (by weight) of filler for asphalt mix for any given type of filler.

Alternative Additives for Improving the Functional Characteristics and Performance-Based Behavior of Asphalt Mixes in the Fine-Grained Active Filler Form

“…3. The Contemporary Materials and Technologies in Civil Engineering maximum density take in all variants, including variants of PVB (2.328 g/cm 3 ), an average of the same values -2.360 g/cm 3 .…”

“…In this case no additional limestone filler was selected for application. First substituting material of filler was a pulverized limestone from quarry Čertovy schody with specific weight to 2.57 mg / m3 (2.57 × 10 -9 g / cm 3 ), the residual weight on 0.125 mm sieves is in the range of 5-15 % and on 0.063 mm sieve 20-30 %. For second set of alternative asphalt mixtures alternatives in the form of micromilled limestone dust or excess cuttings from the processing of limestone boards form, blocks and tiles were selected.…”