On the Recent Trends in Expansive Soil Stabilization Using Calcium-Based Stabilizer Materials (CSMs): A Comprehensive Review

Table 1

Various classification and characterization criteria available in the literature for expansive soils using basic geotechnical tests.

#1 on the basis of swelling [41]
Swell potential	Total expansion	Swell pressure			Degree of expansion
		US customary (tsf)	SI units (kPa)	Metric units (kg/cm^2)
0–1.5	0–10	<2.05	<196	<2	Low
1.5–5	10–20	2.05–4.1	196–392	2–4	Medium
5–25	20–35	4.1–7.2	392–687	4–7	High
>25	>35	>7.2	>687	>7	Very high
#2 on the basis of Atterberg limits [42]
Linear shrinkage	Shrinkage index	PI	LL	SL	Expansivity index
0–8%	<25%	<18%	<35%	<14%	Low
8–13%	25–35%	18–25%	35–45%	12–14%	Medium
13–18%	35–50%	25–35%	45–60%	10–12%	High
>18%	>50%	>35%	>60%	<10%	Very high
#3 on basis of free swell ratio (FSR) [43]
FSR	Soil expansivity	Clay type		Dominant clay mineral
<1	Negligible	Nonswelling		Kaolinite
1–5	Low	Swelling and nonswelling		Kaolinite and montmorillonite
1.5–2	Moderate	Swelling		Montmorillonite
2–4	High	Swelling		Montmorillonite
>4	Very high	Swelling		Montmorillonite
#4 on the basis of liquid limit (LL)
LL	Classification
0–20%	No swell
20–35%	Low swell
35–50%	Medium swell
50–70%	High swell
70–90%	Very high swell
#5 U.S. Army Waterways Experiment Station (WES 1983)
Classification of potential swell		Swell potential (%)	LL (%)	PI (%)	Soil suction (kPa)
Low		<0.5	<50	<25	<160
Marginal		0.5–1.5	50–60	25–35	160–430
High		>1.5	>60	>35	>430
#6 China Ministry of Construction (CMC 2004) [44]
Standard absorption M.C (%)		PI (%)	Free swell value (%)		Swell potential class
<2.5		<15	<40		Nonexpansive
2.5–4.8		15–28	40–60		Low
4.8–6.8		28–40	60–90		Medium
>6.8		>40	>90		High