Table 9. Effect of portland cement on frost heave (after Lambe
and Kaplar 1971).
Heave ratio
Additive
Boston blue
New Hampshire Sandy clay
Type
Percentage
clay (CH)
silt (ML-CL)
(CL)
Portland cement
1
1.35
1.74
1.04
2
2.15
0.63
0.81
3
0.46
0.45
1.08
3*
0.16
0.49
5*
0.17
0
Portland cement
1 + 0.1
1.35
0.59
0.67
and pozzolith
3 + 0.2
0.56
0.74
* Results of tests run at a later date.
sitive to density (2% change), then the results for
greater than 1 means that the stabilized soil was
the first set of tests are suspect. The densities of the
more frost-susceptible than the unstabilized soil.
test specimens varied by 5%. Croney and Jacobs
The freezing tests were conducted on 32-mm-
diameter and 79-mm-tall samples (1.25 3 in.).
(1967) found that by increasing the molding dry
density by 10%, they were able to reduce frost
The results presented in Table 9 are for portland
heave in silty clays by 30%. Upon increasing the
cement soil mixtures and are for one freeze
dry density by 15%, frost heave was reduced by
sequence, i.e., the samples were not subjected to
approximately 60%. It is unlikely that a 2% change
freezethaw cycling. The authors suggest that if
in density would produce a 23% change in frost
their samples were subjected to freezethaw
heave. Croney and Jacobs (1967) also reported that,
cycles, the results would be different from those
for noncohesive soils, density had no effect on frost
presented in Table 9. A CH material with up to 2%
heave.
portland cement added actually experienced an
However, Lambe et al. (1971) suggest that,
increased heave rate, which translated into more
based on their second set of tests, reducing frost
heave. A similar result was found with 1% port-
heave to any significant level will require about 3
land cement added to the ML-CL soil. With 3%
and 5% portland cement in silts (ML-CL) and lean
portland cement, the rate of heave was reduced to
clays (CL). However, as shown above, this result is
46 and 45% for the CH and ML-Cl soils. No im-
not conclusive.
provement was seen with the sandy clay. In an-
Croney and Jacobs (1997) found that the addi-
other study Lambe et al. (1971) found that adding
tion of cement to cohesionless soils reduced frost
3% cement to the ML-CL material reduced the rate
heave to the non-frost-susceptible category (Fig.
of heave to 16%, and for the sandy clay heave was
10). The amount varied from 2.5 to 8%. With frost-
reduced 49%. Although the sandy clay had the
susceptible gravels, they reported that 2% cement
same gradation, it was different as shown in Table
was sufficient to significantly reduce frost heave.
10.
Lambe et al. (1971) reported frost heave results
As seen in Table 10, the major difference
on soils stabilized with lime. The same soils were
between the first and second sets of tests was the
used in the portland cement tests discussed above,
density of both materials, which were higher in
with the exception of the Boston blue clay (CH).
the second set. If the rate of frost heave is that sen-
Table 10. Properties of New Hampshire silt (ML-CL) and Fort Belvoir sandy
clay (CL).
Average
water content
Avg. rate**
γd
Percent
Void
Percent Before
After
of heave
Heave
(kN/m3)
Soil
cement
ratio
sat.
freezing freezing % heave
(mm/day)
ratio
ML-CL*
3
15.7
0.74
91.5
24.4
35.3
21.2
1.08
0.46
ML-CL†
3
16.0
0.68
90.9
22.5
28.3
16.3
1.39
0.16
CL*
3
16.8
0.58
88.5
18.9
31.6
27.4
1.60
1.08
CL†
3
17.5
0.52
98.8
18.9
21.0
13.3
1.21
0.49
* Lambe and Kaplar (1971).
† Lambe et al. (1971).
** 1 in. = 25.4 mm.
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