| Description |
ix, 71 leaves : illustrations ; 29 cm |
| Summary |
"The use of crushed waste glass as an aggregate in asphaltic concrete has been suggested as a means for re-using glass separated from municipal refuse. Laboratory studies and field installations have generally utilized clean glass obtained by hand sorting bottles from the other refuse and crushing them to produce a desired gradation. For this type of asphalt to be economical though, the glass fraction must be separated mechanically. For mechanically separated materials, the glass-rich fraction also contains such items as metal, bone, rubber and other non-glass materials. The objective of the study was to determine the effects upon Marshall properties of laboratory compacted conventional asphaltic paving mixtures when clean glass aggregates and glass-rich fractions were substituted for varying proportions of the conventional aggregates. Five glass-rich fractions with varying gradation and composition were substituted for conventional aggregates in an asphaltic concrete at 10, 30 and 50 percent replacement levels on selected sieve sizes. Similar substitutions were made using clean glass at the same replacement levels and control specimens containing no glass were made for comparison with the specimens containing glass. Marshall properties of all specimens were determined and a statistical analysis was used to determine the relationship between glass addition level and changes in Marshall properties. The results showed that glass-rich fractions and clean glass materials of selected sieve sizes can be substituted for conventional aggregates in asphaltic concrete without causing flow, stability or voids in the mineral aggregate to fall outside limits specified by The Asphalt Institute. In some cases, air void limits were exceeded when increasing amounts of glass-rich fractions were added. Additions of fine incinerator residues caused air voids to increase to a greater degree than was caused by clean glass additions. Since air voids can be adjusted by modifying gradation and/or asphalt content it was concluded that glass-rich fractions can replace portions of the conventional aggregate in an asphaltic concrete with the resulting mixture satisfying Marshall design criteria"--Abstract, leaves ii-iii. |
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