Norna Aashto

Correction for Coarse Particles in the Soil Compaction lkst

I.

SCOPE

1.1 This nicthcd dcscrihcs a prcwdurc whereby the ~naxilnuln soil dcrisity drtcrrriirlctl by AA5H'TO 1' 9Y nr .' 180 I rilay bc adjusted to co~iipensatcfor diffcrilic prcrntagcs of coarse particlcs retair~cdon tlic 4.75 mrn sievc when perfilirninp the (tensity of soil ant1 soilapprcgnle in-place. 1.2 .I hcft~llowingapplies lo all specificd limits in Ihis standard: For thc pilr[urns of drtcrrnining confc~rma~ice with these spcificatinriz. an ohzcrvcd valrlc or a calcr~latetJvalue shall hc rounded trff to tlic nearest unit in the last right-hand place of figures used in cxprcssing ttic liri~itirip value. in accordance with tlie rorir~dinp-off rnett~xl AASII.1'0 R I I , 01 Prcc~riimcri~lcd Practicc ForIndicating lYt11c.11 Places of Figures Are 7b Be Considcrcil Sigriiricallt In Specified Lirriiting Val11e~.

2. 0ll.fLINE OF hlETllOU
l 1 2.1 Whcn h k t l ~ n A lrr Mctl~tnl 1 of YY or 'r I XO is cnlploycd. the maxi~iium tlcnrity ~Iiall1% dctcrlninctl on tile soil tile fraction pa~sing 4.75 nim sievc. 2.1.1 The corrcction chart (Figure I) frlr hfcthid A or h l e t h ~ d of 7 9 9 or II ' 7 180 willdctcrniine the corrected rnaxi' rnurll density from thc pcrccntage c~f coarcc particles retained on tlie 4.75 rnrn sieve that niay hc found whcn performing the tlcncity of soil anit ?oil-aggregate in-place. 2.2 WhenhfetkdCorMethcxlDof 'I' YY or T 180 is employed, thc maximum dsncity shall t tleterrnined on tlie soil w fractiori passing the 19 nim sieve. chart (Figure 2) 2.2.1 The co~rection frvrhlctlird C or Method V will determine thc adj117tcdniaximuni dry density from

tlie percentage of coarse particles retained on tllc 4.75 tnm sieve that may bc found when perforniing the density of soil and soil-aggregate in-piace. 2.2.1.1 Figure 2 shows the maxiniuni dry dt:nsity may o r may not be determined on co:irsc particles replaced as specified under T 9 9 or T 180, Note 7 and Note 8.However, tlie total percentage of coarse particles passing the 19.0 mm and retained on the 4.75 nim sieve will have to be determined along with the percentage of coarse particles (plus 4.75 mm sieve) found when perforniing the density of soil and soil-aggregate in-place. 2.2.2 The corrcction chart (Figure 3) for Mt:tliod C or Method V will determine tlic adjusted maximum dry density from thc pcrcentagcof coarse particles retained On lhc 19.() rrllll sicvc that niaY be found whcn performing the density of soil and soil-aggregate in-place (Appendix A1.2 and A1.2.l). 2.3 Significant figures are as follows: 2.3.1 Maximum dry density of the fine material passing the No. 4 (4.75 mm) sieve (Dl) 0.1 pcf. 2.3.2 Uulk specific gravity of the coarsc material retained on the No. 4 (4.75 mln) sieve (I),)0.01. 2.3.3 Percent by weight of coarse particles of material retained on the No. 4 (4.75 ~lini) sievc expressed as a dccinlal (P,) 0.001. 2.3.4 Adjusted maximum dry density of the total material (D) 0. I pcf.

containing a diffcrent percentage of cc:arse particles is:

D = (1 .(lo - P,)i>/ .I- 0.9 P,D,
where: adjt~sted fiinsir~iurli dcnzity of dry the total matcrial. pcf. P, = percent byweight of coarse piirticles retaincd on thc 4.75 mni sieve in the sariiplc, expressed as a dccimal, Df = maxirnuni lahoratory dry density of the finc material passing thc 2-75 mril sieve. pcf: and D, =. 62.4 x buik specific gravity (ovendry basis) of thc c o a m par!iclcs retained cJn the 4.75 mni sieve, pcf.

D

-

NWTE--In the above equatitn~AVIcir;np!iny ccleff,cientthat is dcFnd0.9 is an Acoefficient of 0,9 is ent on the value of norma~lV considered be in field
" ,

trol of earthwork or base c o u m cmstn~cticm.If a more exact adjustment of ttre maxl~numdcnsity is desired, thc following equaticln may he used:

where:

G , = bulk specific gravity of tlie 1~;lrri-

PI
r

3. ADJ USTMENT EQUATION
3.1 The empirical equation for adjusting the niaximum density obtained in...