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UNIYERSIII TECSNOLOGI PETRONASCIVIL ENGIMERING ?ROGR.{MMEBANDAR SERT IS(ANDAR31750 TRONOEPERAK DARUL RIDZUAN .

TEST 11 : MARSEALL MIX DESIGN

References:

BS598: 1985ASPI{ALT INSlTruIE

Objectives:

To introduce the student to a Marshall mix design mefhod to design bituminous mix forroad paveme[t.

Equipment:

l. Clralory tesring machine2. Mecbaoical mixer.r. I o€rlnomelet4. Water bath5. Elecnonic balaace6. Buoya-ocy baiance7. Oven8. Marshall testing machioe

General Discussion

The design of a bih]minous mir involves the choice ofaggegate q?e, ag$egate giading,bitumen grade and fre deterndnatioo of a bitumen content whiih will optirnise theengioeering properties in relation to the desired behaviour in servjce. While theimportance ofthe fusl three is trot underestioated, the majority ofdiscussioq and researchhas been centred on the methods of arriving at a design bitumen cootent, wherea,s inrecipe specifications the bihqen conteof is selected solely on the basis ofexperience, Indesign methods the choice ofbitunetr cootent is based in wbole or in pad upon the resultsobtaioed in oue or other laboralory test procedure.

in order to desigl a bituninous nh by laboratory procedurcs, with the aim ofproducingthe requbed density aod engineering properties, if is desinbl€ lo prepare specimei:s wbichreproduce, as closely as possible, the matixial tbat wilt be used in iractici. The packiugcharacteristic-s of the aggregates significantly inlluence the mix priperties which cannoroe iusessed trom gadrng curves, as these assume uniformify of particle shape, surfacerougbness aad specific gravity, Evaluation of compacted specinens takes itrto accountthese agg'egare factors. IdearJy specimens shourd bi compacted to the same thiclcress asused ln prachca, by rollitrg, to a density similal to that attai[ed uoder Faffic during theseryile life. However, this is not done io any cuEeot mix design procedure, andspecimeru prepared for routine mix designs are compacted by haron"i. ioltiog t"od" toorieotate €lotgated and flaty aggregate particles so Lbat O"ir.loogest dilreosion s ar.tronzoltal; tius tbe specmels tend to be more aoisoh.opic tlan those prepared byha.@Iner:

flowing the masses.a.od the specific gravities of the mix componenls and the de$ify of.tre corupacted m-|q the volumeric composition can be derermined Tbe samples are lben

test€d to assess their relative resistarce io deformation using either tne Marshill test or tnecleep test.

Proceduret

(A) ; Preparatlon ofAsphalt SpecimensL All ma reria ls are- ba tcbed aod kept in ao oven at 150"C. The mlxer is also heated ro

rre same tevet ot tempemture, therefore great care should be exercised wheo baodliagthe bot material and equioment.

2. The batched graaular miterial Utus fillerl should be placed in rbe mixer and mixedory to! about I lornute, fien l_he approprjate amounf ofbitumen should be added to the

- aggregate, Mixing shor_rld contioue uttil all particles are coated with bihrmeo.

L Tbe material should also be compacred jn tbO mm diamerer steel .oula. (*n.f, *.atso kept ar I50"C - 160,C). Aier filLing rie mould wir! tbe appropriare amounr orErate.ial, the opeEtor should make sure that it is evenJy dist-ibuted- in ihe mould. Thisis dooe by umpjng t-he marerial (usirg steel rod) Ji times a.rouud rhe edges a_od 5P::

t 9t.:""T: . lt d.t. l".ga lhe saople is rerdy for compaction using tbe

Uyratory festing Machine which is set to rhe lollowi_ng standard coodirions:

= 0.7 MPaAlgte of G',radooNo. ofreyolutioos = 30

When tbe specimens haye cooled do*! to room tenperatue, they arc extruded h.orlF:

*g$e, Tbe weight ofeacb specimeo in air ard water and its height rnoota U"taketr (l'or d€nsjty calculatioDs ).Tbree speciuens are to be prepared for each bitumeD conteat.

Axial load

5.

4.

/ 6.7.

5, Conect tle stability value obtaioed above (in order to take into account thedineasions ofthe sample) by the appropriate coeffcienlRead also the deformation at fadur€.From lbe dat& plot the following relationships:

Delsity vs. bihmen contetrtStability ys. bitumetr contetrtPorcsity ys. bihmeD cotrtentFlow ys. bitumen conaent

8. Io ihe light of the data obhined nake cornments regarding the suitability of asphaltmltes for use in road surfacines.

Coefficie!t Factor Jor Ad ust Stabili Yalues,Volume of Specimen Appror:matc Thickless ol Correctiolr CoefficieDt

200-2t3214-225226-237238-250

265-276277-289290-301302-31631',7,328329-340341-353354-357368-379380-392393-10540642042r431432-44344+45615',7 4'10471-482483495496-508509-522523-535536-54654'.7-559560-57357,{-585586-598599-6106tt-625

2.542.702.863.023.18

3.493.653.813.974.r34.294.454.601.',7 64.925.08

5,105.565.725.886.036.196.t56.516.676.836.997.t4134

'1.62

5.565.004.55

3.853.513.333.03i.t s2.502.212.081.92I. '/91.671.56

1.391.32t.251.191.141,091.0,11.000.960.930.890.860.830.810.780.76