Determining the Shrinkage Limit of Soil - Soil Properties: Testing, Measurement, and Evaluation - page 103

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CHAPTER NINE

CHAPTER NINE

Determining
the Shrinkage
Limit of Soil

Determining
the Shrinkage
Limit of Soil

(Referenced Document: ASTM D 427)

As discussed in Chapter 7, the shrinkage limit is the dividing line
between the semisolid and solid states. It is quantified for a given soil
as a specific water content, and from a physical standpoint it is the
water content that is just sufficient to fill the voids when the soil is at the
minimum volume it will attain on drying. In other words, the smallest
water content at which a soil can be completely saturated is the shrink-
age limit. Below the shrinkage limit, any water content change will not
result in volume change; above the shrinkage limit, any water content
change will result in accompanying volume change (see Figure 9-1).
Another soil parameter that is often determined in conjunction
with the shrinkage limit is the shrinkage ratio , which is an indicator of
how much volume change may occur as changes in water content above
the shrinkage limit take place. The shrinkage ratio is defined as the
ratio of a given volume change, expressed as a percentage of the dry vol-
ume, to the corresponding change in water content above the shrinkage
limit, expressed as a percentage of the mass of oven-dried soil. In equa-
tion form,

INTRODUCTION

¢ V

V o

>

R (9-1)

¢ w

M o

>

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