LABORATORY INVESTIGATIONS ON MARBLE SLURRY AS A FILLER IN DENSE BITUMINOUS MACADAM GRADE- I

Abstract

This Bituminous mixes are used in a flexible pavement to serve structural strength, sub-surface drainage,
surface friction etc. Bituminous mixes classified based on nature of their gradation dense graded, semi-dense graded,
open graded, gap graded etc. Dense graded bituminous mixes are most commonly used in bituminous pavements as
binder course. Bituminous mixes consist of coarse aggregates, fine aggregates, filler and binder blended as per
Marshall Mix Design. As natural materials used for highway construction being exhaustible in nature and their
quantity is declining gradually that must be taken care of therefore present study investigate the suitability of marble
slurry as filler with conventional stone dust.
Marble processing unit produce marble slurry during processing of large size block into flat small size slab. This
Slurry is a suspension of marble fines in water, generated during processing, polishing etc. This slurry is no longer
use in industry and left in low laying area, in open fields, pits or anywhere else. In rainy season marble slurry
infiltrate into pores of soil with water which results into reduction in porosity of soil and increases alkinity of soil.
Fine marble dust suspends in the air and is slowly spread out through winds to the nearby area. It settles down on
crops and vegetation, thus severely threatening the ecology of the marble clusters. It causes respiratory ailments in the
nearby residential areas. When dumped along the catchment area of natural rain water, it results in contamination of
over ground water reservoirs and also causes drainage problem.
So the present study incorporates, use of marble slurry in dense bitumen macadam (DBM) grade I layer with stone
dust. DBM Gr-I layer properties can be improved with the incorporation of waste marble slurry. An experimental
program was conducted to evaluate Marshall Mix properties with marble slurry by using binder VG-40. Marshall
Method was adopted to find OBC with conventional stone dust. Samples were prepared and tested to check whether
they meet the Marshall mix parameter. Aggregate gradation has been taken as per MORTH specification for DBM
Grade-I. Three test specimens were prepared at each bitumen content. In first set, OBC for xi
Conventional bituminous concrete mix was found among varied binder content from 4%, 4.50%, 5.00%, 5.50% and
6.00% by wet of dry mix. In second set, marble slurry blended from 2.00%, 3.00%, 4.00%, 5.00% and 6.00% with
stone dust at determined OBC. At each marble content three specimen were prepared and tested. Properties of marble
slurry bitumen binder compared with MORTH specification. It is found that stability increases up to 4% marble
content and then start decrease up to 6.00% at marble content. Flow value continuously increases from 2.20 mm at
2% marble content to 3.30mm at 6% marble content. Bulk density increases from 2.612 gm/cc at marble content 2% to
2.671gm/cc at 6% marble content. Percentage air voids continuously decreases from 4.96% at 2% marble slurry to
4.07% at 6% marble content. Voids in mineral aggregates (VMA) continuously reduce from 14.366% at 2% marble
content to 13.541% at 6.00% marble content. Voids filled with bitumen (VFB) continuously reduce from 69.50% at
2% marble content to 66.50% at 6% marble content.