ABSTRACT
In order to characterize the effect of grain-size distribution on the behaviour of typical Quebec base UGM, the three aggregate sources were sieved into narrow granular fractions (Passing/Retained (mm/mm): 31.5/20, 20/14, 14/10, 10/5, 5/2.5, 2.5/1.25, 1.25/0.63, 0.63/0.315, 0.315/0.16, 0.16/0.08 and 0.08/0). The sieved UGM were then blended in the laboratory with the appropriate proportions to obtain samples having the gradations presented. Table 2 presents the main materials index properties determined in the characterization. The values ρdmax, ρs, wopt, Abs. and BV represents the modified proctor maximum dry density, the grain density, the optimum water content, the absorption value and the methylene blue value. The mixes volumetric characteristics at maximum dry density are the porosity nopt and the fine fraction porosity nfopt (Côté and Konrad 2003). The latter is expressed by:
n V
V n
n n F n n
n F n Ff
c = =
+ − = =
−
−( )% %
( % )1 1 (1)
in which nf = fine fraction porosity, %F = fine particles content, n = porosity, nc = coarse fraction porosity, VVF = voids volume in the fine fraction and VVC = voids volume in the coarse fraction. In addition, the percentage of the loose unit weight of the coarse aggregate %LUWCA determined by volume, the percentage of the rodded unit weight of the fine aggre-
gate %RUWFA determined by volume, the voids within the coarse aggregates at loose unit weight %VCA and the voids within the fine aggregates at rodded unit weight %VFA are also presented. Those volumetric characteristics are determined with unit weight tests and provide useful indications about the blend and particle properties (shape, roughness, etc.).
