Data are reported on the shrinkage and desiccation cracking exhibited by be
ntonite-enhanced sand mixtures (BES) upon air-drying. Mixtures containing 1
0 and 20% bentonite by dry weight, compacted at moisture contents ranging f
rom 8 to 32%, were investigated. Hydraulic conductivity data for BES specim
ens saturated and tested immediately after compaction, and for similar spec
imens that had no visible damage after air-drying, are also presented.
All the mixtures exhibited volumetric shrinkage upon air-drying with the am
ount of shrinkage increasing with increasing moisture content during compac
tion. Ar any initial moisture content mixtures containing 20% bentonite shr
ink more than those containing 10% bentonite, but the shrinkage is insensit
ive to the compactive effort. Compacted beds of BES containing 10 and 20% b
entonite exhibit no visible desiccation cracking as the top surface is drie
d when compacted at 15 and 14% moisture content, respectively, and only min
or cracking when compacted at initial moisture contents of 20 and 15%, resp
ectively. For the range of mixtures tested, it appears that cracking only o
ccurs when BES undergoes more than about 4% volumetric shrinkage when air-d
ried. The saturated hydraulic conductivity of intact BES specimens is unaff
ected by a drying episode prior to testing. (C) 2001 Elsevier Science B.V.
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