SCEBs - University of Colorado Boulder

the sample and not the entire soil sample itself. The cohesive nature of clay supplies the
binding forces between particles in the soil mix matrix. While a higher percentage of
clay would imply more cohesion and therefore a stronger SCEB, the silt portion also
contributes to the range of particle sizes in the soil mix. The silt particles may increase
the overall density of the SCEB, enhancing its performance. This topic needs to be
researched further, before a definitive conclusion can be made regarding an ideal silt/clay
ratio for a suitable soil in SCEB production.
Percent Passing
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Grain Size Distribution Curve: "Sand 1 of 4"
Percent Finer by Weight
Silts & Clays Fine Sand Medium Sand Coarse Sand Gravel
0.01 0.1 1 10
Grain Size (mm)
Figure 4.12: “Sand 1 of 4” Grain Size Distribution Curve
4.2.2.2. Preparation of Soil Mixtures
To illustrate the effects of varying the soil mix ratio on unconfined compressive
strength, model-size (2.5” x 3.5” x 1”) SCEBs were produced. UMU soil Sample #11
was used to produce mini-blocks in accordance with the procedure described in Section
3.6. Four soil mixes with clayey soil to sand ratios varying from 1:2.5 to 1:4, were used
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