Treatment of a collapsible soil using a bentonite–cement mixture

Soumia Bellil; Khelifa Abbeche; Ouassila Bahloul

doi:10.2478/sgem-2018-0042

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Treatment of a collapsible soil using a bentonite–cement mixture

Studia Geotechnica et Mechanica

Volume 40 (2018): Issue 4 (December 2018)

By: Soumia Bellil, Khelifa Abbeche and Ouassila Bahloul

Open Access

|Dec 2018

Figures & Tables

Granulometric curve of the collapsible soil.

Compaction curves of the untreated and treated soils obtained by wetting.

Variation of(γdmaxwopt)$\left( \frac{{{\text{ }\!\!\gamma\!\!\text{ }}_{\text{dmax}}}}{{{\text{w}}_{\text{opt}}}} \right)$as a function of the mixture content (bentonite–cement).

Variations of tangential stresses of control soil (SNT).

Variations of the tangential stresses of the various mixtures before and after treatment.

Evolution of the cohesion (C) and the internal friction angle (φ) in the different mixtures.

SEM and EDS analyses of control soil (SNT) without treatment.

SEM and EDS analyses of the soil treated with various dosages of (10% bentonite+2% cement)

SEM and EDS analyses of soil treated with (8% bentonite+4% cement) and (6% bentonite+6% cement).

SEM and EDS analyses of soil treated with (4% bentonite+8% cement) and (2% bentonite+10% cement).

Chemical compositions of the different soils used_

Constituents (%)	Sand (%)	Kaolin (%)	Reconstituted soil (SNT) (%)	Bentonite (%)	Cement (%)
SiO₂	37.87	19.11	19.35	27.47	6.62
Al₂O₃	2.31	17.00	13.48	10.24	2.27
Fe₂O₃	1.63	1.15	1.29	1.71	2.30
CaO	5.41	0.14	1.86	1.08	40.30
MgO	0.54	0.28	0.46	1.55	0.65
K₂O	0.60	1.57	0.91	5.70	1.32

Geotechnical characteristics of different soils_

Sand (<2 mm)	Coefficient of uniformity, C_u	2.78
	Coefficient of curvature, C_c	1.05
	Sand equivalent, Es (%)	74.01
	Specific density, G_s	2.66

Kaolin (<80 mm)	Liquidity limit, W_l (%)	48.52
	Plasticity limit, W_p (%)	33.82
	Specific density, G_s	2.70
	Activity, A_c (%)	1.20

Reconstituted soil (SNT)	Coefficient of uniformity, C_u	2.81
	Coefficient of curvature, C_c	1.05
	Liquidity limit, W_l (%)	21.64
	Plasticity limit, W_p (%)	16.79
	Sand equivalent, E_s (%)	65.93
	Specific density, G_s	2.65
	Dry density, gd_max (g/cm³)	1.90
	Optimum water content, W_opt (%)	10.42

Bentonite (powder)	Specific surface area , SSA (m²/g)	872.00
	Bulk density, G_s	2.72
	Swelling index ,SI (cm³/g)	35.00
	Plate water absorption ,PWA (%)	885.00
	Blue methylene value, MBV	29.41
	pH	9.90
	Plasticity index, I_p (%)	117.54

Cement (CPJ 42.5 CEM II/A)	Specific weight ,Gs (g/cm³)	3.04
	Normal consistency , NC (% H₂O)	27.44
	Shrinkage , Wr (mm/m)	417.00
	Refusal on sieve 45 mm, RS (%)	12.42
	Compressive strength at 28 days,CR	44.07
	(MPa)

Variations of the different mixing ratios of the components (bentonite–cement)_

Untreated soil (sand+kaolin)	Soil treated with [bentonite (B)+cement (C)]
SNT (75%+25%)	SNT + (10%B+2%C)
	SNT + (8%B+4%C)
	SNT + (6%B+6%C)
	SNT + (4%B+8%C)
	SNT + (2%B+10%C)

Variation of the collapse potential Cp of the treated and untreated soils_

Type of soils	Water content (%)	4			6			8
	Number of strokes, E_c	30	50	70	30	50	70	30	50	70
SNT	e₀	0.504	0.465	0.429	0.500	0.451	0.403	0.497	0.446	0.396
	S_r (%)	21.328	23.767	26.767	31.800	35.255	39.454	42.063	45.591	49.417
	C_p (%)	8.350	5.232	3.578	8.166	5.105	3.104	7.712	4.390	2.239
SNT+ (10%B+2%C)	e₀	0.491	0.459	0.426	0.487	0.444	0.400	0.486	0.440	0.393
	S_r (%)	18.271	20.181	22.595	27.351	30.000	33.300	36.171	38.700	41.700
	C_p (%)	6.796	4.722	2.153	6.392	4.239	2.000	5.750	3.818	1.753
SNT+(8%B+4%C)	e₀	0.469	0.447	0.419	0.467	0.428	0.396	0.459	0.425	0.389
	S_r (%)	19.172	20.705	22.622	28.265	30.841	33.334	37.526	39.373	42.004
	C_p (%)	2.393	1.539	1.054	2.129	1.519	1.047	2.097	1.502	0.565
SNT+(6%B+6%C)	e₀	0.480	0.453	0.422	0.477	0.436	0.398	0.473	0.433	0.391
	S_r (%)	18.700	20.415	22.608	27.800	30.412	33.316	36.834	39.028	41.895
	C_p (%)	2.764	2.456	1.439	2.362	1.591	1.432	2.074	1.464	0.916
SNT+(4%B+8%C)	e	0.451	0.437	0.410	0.446	0.413	0.392	0.437	0.412	0.384
	₀ S_r (%)	20.411	21.650	23.230	30.000	32.400	34.132	39.556	40.823	43.512
	C_p (%)	1.500	0.706	0.662	1.659	0.495	0.462	1.102	0.209	0.220
SNT+(2%B+10%C)	e₀	0.460	0.442	0.415	0.457	0.420	0.394	0.447	0.418	0.386
	S_r (%)	19.686	21.052	22.800	28.884	31.428	33.502	38.260	39.819	42.409
	C_p (%)	1.559	0.789	0.797	1.754	0.560	0.516	1.433	0.578	0.336

Geotechnical characteristics of soils_

Soils	W_l (%)	W_p (%)	W_opt (%)	gd _max (g/cm³)
SNT	21.64	16.79	10.425	1.900
SNT+ (10%B+2%C)	32.49	24.59	13.235	1.804
SNT+ (8%B+4%C)	32.20	25.49	13.154	1.810
SNT+ (6%B+6%C)	32.05	25.61	11.015	1.826
SNT+ (4%B+8%C)	25.32	21.12	10.606	1.861
SNT+ (2%B+10%C)	23.32	19.50	10.602	1.884

Geotechnical characteristics of the different mixtures_

Soil types		SNT	SNT+ (10%B+2%C)	SNT+ (8%B+4%C)	SNT+ (6%B+6%C)	SNT+ (4%B+8%C)	SNT+ (2%B+10%C)
w₀ =	C (kPa)	34.76	63.70	83.09	76.71	104.54	88.51
4%	φ (°)	37.68	27.74	23.22	23.79	18.60	23.02
w₀ =	C (kPa)	33.33	60.00	79.37	71.45	102.29	85.53
6%	φ (°)	35.66	27.02	24.05	24.20	18.37	23.54
w₀ =	C (kPa)	31.36	52.00	69.11	59.54	86.56	77.21
8%	φ (°)	33.20	25.64	21.25	23.63	16.51	19.08

Values of the collapse potentials_

C_P(%)	Susceptibility to collapse
0–1	No problem
1–5	Moderate trouble
5–10	Trouble
10–20	Severe trouble
>20	Very severe trouble

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DOI: https://doi.org/10.2478/sgem-2018-0042 | Journal eISSN: 2083-831X | Journal ISSN: 0137-6365

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Language: English

Page range: 233 - 243

Submitted on: Apr 22, 2018

Accepted on: Nov 10, 2018

Published on: Dec 31, 2018

Published by: Wroclaw University of Science and Technology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

cement,

Related subjects:

Physics,

Mechanics and fluid dynamics

© 2018 Soumia Bellil, Khelifa Abbeche, Ouassila Bahloul, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 40 (2018): Issue 4 (December 2018)

Treatment of a collapsible soil using a bentonite–cement mixture

Figures & Tables

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Chemical compositions of the different soils used_

Geotechnical characteristics of different soils_

Variations of the different mixing ratios of the components (bentonite–cement)_

Variation of the collapse potential Cp of the treated and untreated soils_

Geotechnical characteristics of soils_

Geotechnical characteristics of the different mixtures_

Values of the collapse potentials_

Paradigm

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