Indira Gandhi Institute of Technology, Sarang Dhenkanal-759146

PARTICLE SIZE ANALYSIS

Sieve size	Actual mass retained		% mass retained	Cumulative % mass retained	% finer
4.75 mm		88.861	8.88	8.88	91.12
2.00 mm		155.091	15.50	24.38	75.62
1.00 mm		264.851	26.48	50.86	49.14
600 micron		90.181	9.01	59.87	40.131
425 micron		98.881	9.88	69.75	30.25
300 micron		61.651	6.16	75.91	24.09
212 micron		52.871	5.28	81.19	18.81
150 micron		73.791	7.37	88.56	11.44
75 micron		80.681	8.06	96.62	3.38

From the graph Gravel=24.38%

Sand=73.62%

Silt=2%

Clay=Nil

Uniformity coefficient=245.45 and coefficient of curvature=0.33

As D₆₀ =1.2

D₃₀ =0.43

D₁₀ =0.15

C_u = D₆₀ / D₁₀ =8

C_c = ( D₃₀ × D₃₀)/ D₁₀ × D₆₀=1.03

So from the above we can draw the conclusion that it is a well graded type of soil.

Direct Shear Test

Test no	Normal Stress	Shear stress at failure	Shear displacement at failure in mm
1	0.5	0.75	0.87
2	1.5	1.44	1.65
3	2.5	2.25	2.58

Graph was plotted between normal stress and shear stress and from the graph

Angle of internal friction was found to be 36⁰ and c or cohession value was found to be 0.35.

Unconfined Compressive Strength

Deformation in mm	strain	Axial strain in %	Area(cm2)	Proving ring dial reading	Applied axial load in Kg	Stress in Kg/cm2
0	0	0	9.62	0	0	0
0.5	0.0067	0.67	9.684	6	2.127	0.219
1	0.0135	1.35	9.751	8	2.83	0.290
1.5	0.020	2.0	9.816	11	3.900	0.397
2	0.027	2.7	9.886	13	4.609	0.466
2.5	0.033	3.3	9.948	14	4.964	0.498
3	0.040	4	10.02	16	56.73	0.566
3.5	0.047	4.7	10.09	17	6.02	0.596
4	0.054	5.4	10.169	19	6.73	0.661
4.5	0.061	6.1	10.24	20	7.09	0.692
5	0.067	6.7	10.31	22	7.80	0.756
5.5	0.074	7.4	10.388	23	8.156	0.785
6	0.081	8.1	10.467	24	8.51	0.813
6.5	0.087	8.7	10.536	25	8.86	0.840
7	0.094	9.4	10.618	26	9.21	0.867
7.5	0.101	10.1	10.700	27	9.57	0.894
8	0.108	10.8	10.78	28	9.93	0.921
8.5	0.114	11.4	10.857	28	9.93	0.914
9	0.121	12.1	10.944	28	9.93	0.907
9.5	0.128	12.8	11.032	28	9.93	0.900

A graph was plotted between σ and ε.The maximum stress from this curve gave the value of unconfined compressive strength = q_u =90.32KN/m²

Shear strength c= q_u/2 =45.15KN/m²

Newson et al. (2006) carried out investigations on physiochemical and mechanical properties of red mud at a site in the United Kingdom. Based on a set of laboratory tests conducted on the red mud, the compression behaviour found to similar to clayey soils, but frictional behaviour closer to sandy soils. The red mud appears to be “structured” and has features consistent with sensitive, cemented clay soils. Chemical testing suggests that the agent causing the aggregation of particles is hydroxyl sodalite and that the bonds are reasonably strong and stable during compressive loading and can be broken down by subjecting the red mud to an acidic environment. Exposure of the red mud to acidic conditions causes dissolution of the hydroxyl sodalite and a loss of particle cementation. Hydration of the hydroxyl sodalite unit cells is significant, but does not affect the mechanical performance of the material. The shape, size, and electrically charged properties of the hydroxyl sodalite, goethite, and hematite in the red mud appear to be causing mechanical behaviour with features consistent with clay and sand, without the presence of either quartz or clay minerals.
behaviour closer to sandy soils. The red mud appears to be “structured” and has features consistent with sensitive, cemented clay soils. Chemical testing suggests that the agent causing the aggregation of particles is hydroxyl sodalite and that the bonds are reasonably strong and stable during compressive loading and can be broken down by subjecting the red mud to an acidic environment. Exposure of the red mud to acidic conditions causes dissolution of the hydroxyl sodalite and a loss of particle cementation. Hydration of the hydroxyl sodalite unit cells is significant, but does not affect the mechanical performance of the material. The shape, size, and electrically charged properties of the hydroxyl sodalite, goethite, and hematite in the red mud appear to be causing mechanical behaviour with features consistent with clay and sand, without the presence of either quartz or clay minerals.
Liu et al. (2006) observed that pH value of red mud decreases with increase in duration of storage time and Oxygen(O) accounted for about 40% with other major elements included Calcium(Ca), Iron(Fe), Silicon(Si), Aluminium(Al), Titanium(Ti), Sodium(Na), Carbon, Magnesium(Mg) and Potassium(K) . XRD analysis shows calcite, perovskite, illite, hematite and magnetite are present in red mud and the old red mud also contained some kassite and portlandite. In addition, there are about 20% of amorphous materials in all red mud.

Sundaram and Gupta (2010) have some in-situ investigations on red mud to be used as a foundation material and they have observed that red mud is highly alkaline (9.3-10.2) with liquid limit of 39-45 %, plastic limit of 27-29% and shrinkage limit of 19-22%. They also found that undrained shear strength is 0.4 to 1.4 kg/cm2, specific gravity is 2.85-2.97, cohesion is 0.1 to 0.2 kg/cm2 and angle of internal friction is 26-280.