reinforcement of sand with shredded waste tires

REINFORCEMENT OF SAND WITH

SHREDDED WASTE TIRES

BY SUMAN ROY

A LARGE AMOUNT OF TIRES ARE DISPOSED

OF EVERY YEAR.

IN ORDER TO AVOID STOCKPILES, TIRES ARE

USED AS A RECYCLING MATERIAL.

WASTE TIRES ARE USED TO ENHANCE SHEAR

STRENGTH OF SOIL.

SHREDDED WASTE TIRES ARE NOW USED AS

CONSTRUCTION MATERIAL.

SUB GRADE REINFORCEMENT

AS SOUND BARRIERS

TRUCK BED LINERS, DOORMATS, AND CUSHIONING

FOAMS

OBJECTIVE OF TEST:

FEASIBILITY OF USING SHREDDED WASTE

TIRES TO REINFORCE SAND.

OBJECTIVE OF TEST:

FEASIBILITY OF USING SHREDDED WASTE

TIRES TO REINFORCE SAND.

SAND USED:

DRY PORTAGE SAND

PROPERTIES OF PORTAGE SAND USED COEFFICIENT OF UNIFORMITY OF 1.0

A COEFFICIENT OF CURVATURE OF

1.0

SPECIFIC GRAVITY OF 2.68.

THE MINIMUM UNIT WEIGHT

OF THE SAND IS 15.5 kN/M3 AND THE

MAXIMUM UNIT WEIGHT IS

17.7 kN/M3

PEAK FRICTION ANGLE OF 25°WHEN

ITS UNIT WEIGHT IS 15.5 kN/M3

AND 34° WHEN ITS UNIT WEIGHT IS

17.7 kN/M3

PROPERTIES OF SHREDDED TIRES USED

DIVIDED IN THREE GROUPS:

5 CM

10 CM

15 CM

DIRECT SHEAR MACHINE

STAINLESS STEEL SHEAR RINGS

INSIDE DIAMETER =27.9 CM

TOP AND BOTTOM HALVES OF THE SHEAR RING

HEIGHT =15.7 CM .

RATE OF DISPLACEMENT =0.13 CM/MIN.

A COMPUTERIZED DATA ACQUISITION SYSTEM

WAS USED TO RECORD THE DATA.

PREPARATION OF SPECIMEN

ONE-FOURTH OF THE TIRE SHREDS NEEDED TO

ATTAIN THE DESIRED TIRE SHRED CONTENT WERE

INITIALLY HAND PLACED IN THE BOTTOM OF THE

RING.

PREPARATION OF SPECIMEN

ONE-FOURTH OF THE TIRE SHREDS NEEDED TO

ATTAIN THE DESIRED TIRE SHRED CONTENT WERE

INITIALLY HAND PLACED IN THE BOTTOM OF THE

RING.

SAND WAS RAINED INTO THE SHEAR RING ON TOP

OF THE SHREDS IN A CIRCULAR MOTION

PREPARATION OF SPECIMEN

ONE-FOURTH OF THE TIRE SHREDS NEEDED TO

ATTAIN THE DESIRED TIRE SHRED CONTENT WERE

INITIALLY HAND PLACED IN THE BOTTOM OF THE

RING.

SAND WAS RAINED INTO THE SHEAR RING ON TOP

OF THE SHREDS IN A CIRCULAR MOTION

THE SPECIMENS WERE THEN VIBRATED ON A

VIBRATING TABLE UNTIL THE DESIRED SAND MATRIX

UNIT WEIGHT WAS OBTAINED.

FACTORS TAKEN UNDER CONSIDERATION

NORMAL STRESS

SAND MATRIX UNIT WEIGHT

SHRED CONTENT

SHRED LENGTH

SHRED ORIENTATION

NON LINEARITY OF STRENGTH ENVELOPE

VOLUME CHANGE

WHICH FACTORS AFFECTED MOST?

NORMAL STRESS

SHRED CONTENT

SAND MATRIX UNIT WEIGHT

This was found out by YATE’S ALGORITHM

which is a common method for predicting

the factors affecting a test

In this case efficiency of 95% was targeted.

It utilizes t statistics and an aim for t value

greater than 2.262 was targeted.

t distribution

SHRED CONTENT

SAND MATRIX UNIT WEIGHT

A TEST ON TIRE SHREDS ONLY

HIGHER FRICTION ANGLES WERE ALSO

OBSERVED.

ANGLE OF REPOSE OF 45O AND 850 WAS

OBSERVED IN SOME CASES.

WHY THERE IS AN INCREASE IN SHEAR STRENGTH ?

∆S = increase in shear strength of soil

Ar = area of reinforcements

A = area of shear zone

θ = angle of shear distortion = tan-1 (x/z)

φ = angle of internal friction for soil

σt = tensile stress in fiber

However it can also be modified by a model where

tire shreds are assumed to behave as fibers

This is known as Maher and Gray's (1990) model

It includes several other assumptions.

Based on this model value of predicted φ1’ was found

to be closer to the actual value in experiment

SUMMARY

THE SHEAR STRENGTH OF SAND-TIRE SHRED MIXTURES WAS

INVESTIGATED IN THIS STUDY.

THREE FACTORS WERE FOUND TO SIGNIFICANTLY AFFECT

THEIR SHEAR STRENGTH: NORMAL STRESS, SHRED CONTENT,

AND SAND MATRIX UNIT WEIGHT.

FURTHERMORE, IN ALL CASES, SAND CONTAINING SHREDDED

TIRES HAD HIGHER SHEAR STRENGTH THAN SAND ALONE.

STRENGTH ENVELOPES FOR MIXTURES CONTAINING DENSE

SAND ARE NONLINEAR.

INITIAL FRICTION ANGLES AS LARGE AS 67° WERE

OBTAINED WHEN THE SAND MATRIX WAS DENSE.

THE FRICTION ANGLE FOR UNREINFORCED PORTAGE SAND

AT THE SAME UNIT WEIGHT IS 34°.

THE INITIAL FRICTION ANGLE INCREASED AS THE SHRED

CONTENT WAS INCREASED.

SAND MATRIX UNIT WEIGHT IS AN IMPORTANT PARAMETER

AFFECTING THE INITIAL FRICTION ANGLE.

REFERENCES Bosscher, P. J., Edil, T. B., and Eldin, N. (1993). "Construction and

performance of shredded waste tire test embankment." Transp. Res.Rec.•

No. 1345, Transp. Res. Board, Washington, D.C., 44-52.

Box, G., Hunter, W., and Hunter, J. (1978). Statistics for

experimenters.Wiley-Interscience, New York, N.Y.

DEFORMATION CHARACTERISTICS OF REINFORCEDSAND IN DIRECT SHEAR

By Scott E. Shewbridge and Nicholas Sitar, Associate Members, ASCE

SAND REINFORCED WITH SHREDDED WASTE TIRES By Gary J. Foose,Craig H.

Benson and Peter J. Bosscher Members, ASCE

Foose. G. (1993). "Shear strength of sand reinforced with shredded waste

tires," MSc thesis, Dept. ofCiv. and Envir. Engrg., Univ. of Wisconsin

Madison,Wis.

Gray, D., and AI-Refeai, T. (1986). "Behavior of fabric-versus fiber reinforced

sand." J. Geotech. Engrg.• ASCE, 112(8), 804-820

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