1. Susceptibility to Compaction of Lime and GGBS Treated Bauxite Residue
K. Sateesh Babu
Master’s student
&
N. Gangadhara Reddy
Research Scholar
Dr. B. Hanumantha Rao
&
Dr. Partha Patim Dey
Assistant Professors’
IIT Bhubaneswar
Bhubaneswar, India

2. Introduction: Problems and Need of the Study
Red mud is a solid insoluble waste generated by aluminium industry
Utilization: 5%, and 95% of it is stored in impoundments
Problems:
Land acquisition
Construction and maintenance
Leachate generation
Ground, soil and water pollution
High alkalinity: pH above 11
Need:
Alkali (sodium ion) regeneration
Impact on environment
Utilization in civil engineering applications is least explored

3. Characteristics of Red Mud
Low strength due to presence of caustic content
Sodium cations are predominant due to the high NaOH
It is completely free from sand or clayey type mineral constituents
In spite of absence of clay type mineral constituents,
shows plastic behavior similar to that of clayey tailings and
shows significantly low volumetric deformation alike sands

4. Objectives of the Study
To evaluate the compaction characteristics of red mud by adapting chemical analysis methods
To study the influence of Lime and GGBS stabilization on compaction characteristics of red mud

5. Materials & Testing Methodology
Red Mud: collected from Vedanta limited at Lanjigarh, Odisha
Stabilizers
lime of a commercial grade quality is procured from the local market,
GBS & GGBS are procured from M/s. Counto Microfine Products Pvt. Ltd., Panaji, Goa, India.
GBS
GGBS
Lime
Red Mud 5

6. Characterization of Red Mud and Stabilizers
Red Mud: Physical Properties
Property
Value Gs
3.09
Consistency limit (%) wL 40 wP 29
wPI 11
% fractions
Sand
18.3
Silt
55.35
Clay
26.35
Classification MI pH
Chemical Composition: XRF analysis
Oxide
% (by dry weight)
Na2O
6.48
Al2O3
22.72
SiO2
13.43
CaO
4.06
TiO2
10.17
Fe2O3
39.89
MgO
0.64
P2O5
0.47
SO3
0.75
K2O
0.44
others 2
Elemental Composition: EDS analysis
Element
% (by dry weight)
Red Mud
GGBS
GBS
Lime
Iron
34.81
2.77 -
Aluminum
23.38
16.67
15.65
2.03
Silicon
13.42
30.63
34.12
9.77
Titanium
8.68
0.79
Calcium
4.96
42.27
38.61
82.44
Sodium
14.75
Magnesium
6.61
9.96
5.76
Total
100.00
100
Observation:
Iron oxides dominant in Red mud
Strength giving elements dominant in stabilizers

7. Mineralogical Characteristics: XRD
Morphological Characteristics: XRD
Red mud: non uniform particle size
GGBS and GBS: No similarity in shape
Untreated red mud
Lime
Hematite is dominant mineral type
Minerals belongs to Fe family
GGBS
GBS

8. Experimental Program: Stabilization
Additive
% replacement
(by dry weight)
Sample designation
Experimentation
Lime
0.0
RM+0L
Consistency limits: IS:2720 (Part 5)
Compaction Test (Mini compaction by Sridharan)
UCS Test : IS: 2720(Part 10)
CBR Test: IS:2720 (Part 16)
Morphological Characteristics (SEM)
Mineralogical Characterization (XRD)
Elemental characterization (EDS)
Neutralization study
0.5
RM+0.5L
1.0
RM+1L
2.0
RM+2L
5.0
RM+5L
8.0
RM+8L
GBS 10
RM+10%GBS 20
RM+20%GBS
GGBS
90RM+10GGBS 15
85RM+15GGBS
80RM+20GGBS 25
75RM+25GGBS
RM – RED MUD; L-LIME; GBS- GRANULATED BLAST FURNACE SLAG; GGBS- GROUND GRANULATED BLAST FURNACE SLAG

9. Compaction Characteristic
A range of factors affect the compaction of soil:
water content
compaction effort
type of soil
method of compaction, etc.
In natural soils, the oxide compositions variations are insignificant.
Industrial waste materials are increasingly being utilized in geotechnical engineering applications.
Contrary to natural soils, waste materials constitute oxide compositions in disproportionate contents, making them susceptible to compaction.
Influence of certain properties like oxide compositions not received adequate attention.
Variability in dmax & wopt
Sensitive to waste content

10. Results & Discussion: Compaction properties
Red mud : dmax to 17.8 kN/m3, wopt from 27 to 28%
Lime stabilized: decreased dmax increased for 2-5%.
wopt increased up to 1% ,constant beyond this value
GGBS: marginal variations in the values of dmax & wopt
GBS stabilized: no change in wopt, marginal improvement in dmax

11. Values of dmax and wopt of treated red mud waste samples
s.no
Combination of sample
Experimental Results
As per IRC: SP: 20:2002 (Rural roads)
OMC(%)
MDD(gm/cc)
Embankment
Subgrade & Earthen shoulders 1
Raw RM
27- 28
a) Up to 3m, not subjected to Extensive flooding,
MDD shall not less than 1.44 gm/cc.
b) Height exceeding 3m, MDD shall not less than 1.52gm/cc
Recommendation:
Acceptable
MDD shall not less than 1.65 gm/cc
Except 5% Lime treated samples,
all other combinations are Acceptable 2
90RM+10GGBBS
29.70
1.65 3
85RM+15GGBBS
27.314
1.655 4
80RM+20GGBBS
27.5
1.69 5
75RM+25GGBBS
28.29 6
RM+0.5L
26.8
1.696 7
RM+1L
27.6
1.682 8
RM+2L
28.35
1.676 9
RM+5L
29.36
1.606 10
RM+10%GBS
1.68 11
RM+20%GBS
1.71

12. Results & Discussion: Unconfined Compressive Strength
Observation
UCS (Mpa)
Lime
Doubled at 90 days
GBS
Doubled at 90 days, max at GBS 10%
GGBS
Four times at 90 days, max at 15% GGBS

13. Values of UCS for treated samples at different curing periods
Combination of sample
Experimental Results (UCS: MPa)
IRC 37:2012
IRC: SP:
Curing period(days) 7 28 45 90
For chemically stabilized material: 0.75 to 1.5 MPa at 7 days curing period
For subbase: 1.7 MPa
For base course: 3 MPa RM
0.34
0.39
0.44
 0.65
0.70 
90RM+10GGBBS
0.33
0.38
0.47
1.20
1.46
85RM+15GGBBS
0.35
0.386
0.49
1.32
1.84
80RM+20GGBBS
0.36
0.41
0.51
1.22
1.75
75RM+25GGBBS
0.365
0.43
0.48
1.08
1.67
RM+0.5L
0.32
0.45
 0.64
0.68 
RM+1L
 0.66
0.72 
RM+2L
0.42
0.53
 0.67
 0.78
RM+5L
0.52
0.55
0.77 
RM+10%GBS
0.37
0.40
0.46
 0.7
0.74 
RM+20%GBS
0.50
 0.70

14. California Bearing Ratio
Variations of CBR value with Stabilizers at different curing periods
Observation:
Maximum at Lime 5%
Maximum at GBS 20%
Maximum at GGBS 15%

15. Results of California Bearing Ratio tests of stabilized red mud samples
Combination of sample
Experimental Results
IRC 37:2012
IRC:SP:72:2015
Curing Periods(Days) 7
Un soaked
Soaked
soaked RM
18.2
5.4
22.0
6.32
Soaked CBR value:
8% for roads with traffic ≥ 450 CVPD
Recommendation: Only GBS Stabilized samples are acceptable
Soaked CBR value: 4-6%
Recommendation: Acceptable
90RM+10GGBBS
15.7
5.7
21.7
6.92
85RM+15GGBBS
14.9
6.1
21.1
7.4
80RM+20GGBBS
15.12
6.41
21.0
7.9
75RM+25GGBBS
14.80
6.5
22 
 7.58
RM+0.5L
18.5
6.2
 21.4
 6.3
RM+1L
19.6
6.4
 22.4
 6.9
RM+2L
19.8
6.9
 23
 7.4
RM+5L
22.21
7.5
 24
 7.9
RM+8L
21.09
7.1
22.5
RM+10%GBS
20.2
23.4
8.2
RM+20%GBS 23
6.8 26
8.9
RM+25%GBS
22.9
6.78
25.8
8.8

16. Mineralogical characteristics of Lime Stabilized Red Mud
Observation: Increasing the lime content,
peak intensity decreasing
calcite phase prominently increasing.

17. Mineralogical characteristics of GGBS Stabilized Red Mud
Observation:
Increasing the GGBS content,
decrease in peak intensity of hematite
No major change in the various mineral phase

18. Untreated red mud 1% lime 5% lime Morphological characteristics
Observation:
increase in lime content,
Gel formation is increasing
Untreated red mud
1% lime
5% lime

19. Morphological characteristics of Stabilized Samples
RM 90+ GGBS 10
Untreated red mud
RM 90+ GBS 10
RM 85+ GGBS 15
11/27/2018

20. Elemental characteristics of Stabilized samples
Lime
GGBS & GBS
Element
% (by dry weight)
% change RM
RM +05L
RM +1L
RM +2L
RM +5L Fe
34.81
31.78
30.74
28.69
26.24
-24 Al
23.38
22.86
20.76
15.12
15.62
-33 Si
13.42
13.78
12.98
9.10
11.25
-15 Ti
8.68
7.89
7.38
6.06
6.34
-27 Ca
4.96
8.42
13.68
28.79
28.98
+485 Na
14.75
11.87
11.30
10.19
9.66
-34 Mg -
3.4
2.96
2.04
1.92
Sample designation
% (by dry weight) Fe Al Si Ti Ca Na
RM+ GBS 0
34.81
23.38
13.42
8.68
4.96
14.75
RM 90+GBS 10
29.66
23.47
17.55
7.92
7.77
13.62
RM 80+GBS 20
38.44
23.58
13.44
8.49
3.11
12.94
RM 90+GGBS 10
25.78
21.68
20.58
6.40
12.57
10.64
RM 85+GGBS 15
20.54
23.43
23.16
6.36
12.98
10.97
RM 80+GGBS 20
19.04
20.85
23.25
5.26
18.24
9.03
RM 75+GGBS 25
19.80
19.43
24.13
5.08
18.85
7.83
%ge change for GBS
-10.4
-0.855
-0.15
2.18
37.29
12.27
%ge change for GGBS
43.12
16.9
-79.8
41.47
280
46.91

21. Summary
Studies reveal that the red mud susceptible to applied compaction energy, as it is noticed a contrast in the values of dry unit weight and optimum water content
The study finds that addition of 5% lime or 15% of GGBS is advantageous for obtaining reliable and consistent values of maximum dry unit weight and optimum water content.
Comparison with compaction characteristics of the red mud with fly ash and foundry sand shows, the red mud has a potential to be a resource material in the construction of an embankment or a subgrade

22. Thanks for your kind attention
Waste is a waste if you waste it… Otherwise it is a RESOURCE.