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Use of Locally Available Materials and Stabilisation Technique

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Presentation on theme: "Use of Locally Available Materials and Stabilisation Technique"— Presentation transcript:

1 Use of Locally Available Materials and Stabilisation Technique
Dr. M.S. AMARNATH Bangalore University Bangalore

2 Soil Stabilization Basic Principles of Soil Stabilization….
The soil stabilization means the improvement of stability or bearing power of the soil by the use of controlled compaction, proportioning and/or the addition of suitable admixture or stabilizers. Basic Principles of Soil Stabilization…. Evaluating the properties of given soil Deciding the lacking property of soil and choose effective and economical method of soil stabilization Designing the Stabilized soil mix for intended stability and durability values

3 Need for Soil Stabilization
Limited Financial Resources to Provide a complete network Road System to build in conventional method Effective utilization of locally available soils and other suitable stabilizing agents. Encouraging the use of Industrial Wastages in building low cost construction of roads.

4 Methods of Soil Stabilization
Mechanical Stabilization Soil Cement Stabilization Soil Lime Stabilization Soil Bitumen Stabilization Lime Fly ash Stabilization Lime Fly ash Bound Macadam.

5 Mechanical Stabilization
This method is suitable for low volume roads i.e. Village roads in low rainfall areas. This method involves the correctly proportioning of aggregates and soil, adequately compacted to get mechanically stable layer The Basic Principles of Mechanical Stabilization are Correct Proportioning and Effective Compaction

6 Desirable Properties of Soil-Aggregate Mix
Adequate Strength Incompressibility Less Changes in Volume Stability with Variation in water content Good drainage, less frost Susceptibility Ease of Compaction.

7 Factors Affecting Mechanical Stabilization
Mechanical Strength of aggregates Gradation Properties of the Soil Presence of Salts Compaction

8 Mechanical Strength Gradation Properties of soil
When the soil is used in small proportion to fill up the voids the crushing strength of aggregates is important Gradation A well graded aggregate soil mix results in a mix with high dry density and stability values Properties of soil A mix with Plasticity Index, results poor stability under soaking conditions. Hence it is desirable to limit the plasticity index of the soil

9 Presence of Chemicals Compaction
Presence of Salts like Sulphates and mica are undesirable Presence of Calcium Chloride is Beneficial Compaction Effective Compaction is desirable to produce high density and stability mix

10 Soil Cement Stabilization
Soil Cement is an intimate mix of soil, cement and water, compacted to form a strong base course Cement treated or cement modified soil refers to the compacted mix when cement is used in small proportions to impart some strength Soil Cement can be used as a sub-base or base course for all types of Pavements

11 Factors affecting soil cement stabilization
Pulverisation and Mixing Compaction Curing Additives

12 Soil THE PHYSICAL PROPERTIES Particle Size Distribution Clay content Specific Surface Liquid limit and Plasticity Index Cement A increase in cement content generally causes increase in strength and durability

13 Pulverisation and Mixing
Better the Pulverisation and degree of mixing, higher is the strength Presence of un pulverised dry lumps reduces the strength Compaction By increasing the amount of compaction dry density of the mix, strength and durability also increases

14 Adequate Moisture content is to be retained in
Curing Adequate Moisture content is to be retained in order to accelerate the strength Additives There are some additives to improve properties Lime Sodium hydroxide Sodium Carbonate Calcium Chloride

15 Design of Soil –Cement Mix
Soil – Cement specimens are prepared with various cement contents in constant volumes moulds The compressive strength of these specimens tested after 7 days of curing A graph is plotted Cement content Vs compressive strength The Cement Content Corresponding to a strength of 17.5 kg/cm2 is taken as design cement content

16 Soil Lime Stabilization
Soil- Lime has been widely used as a modifier or a binder Soil-Lime is used as modifier in high plasticity soils Soil Lime also imparts some binding action even in granular soils

17 Soil-Lime is effectively used in Expansive soils with high plasticity index.

18 Factors affecting Properties of Soil-Lime
Lime Content Generally increase in lime content causes slight change in liquid limit and considerable increase in Plasticity index The rate of increase is first rapid and then decreases beyond a certain limit The point is often termed as lime fixation point This is considered as design lime content

19 Type of Lime Compaction
After long curing periods all types of limes produce same effects. However quick lime has been found more effective than hydrated lime Calcium Carbonate must be heated at higher temperature to form Quick lime calcium oxide( CaO) Calcium oxide must be slaked ( by the addition of water) to form Hydrated lime Compaction Compaction is done at OMC and maximum dry density.

20 Curing Additives The strength of soil-lime increases with curing
period upto several years. The rate of increase is rapid during initial period The humidity of the surroundings also affects the strength Additives Sodium metasilicate, Sodium hydroxide and Sodium Sulphate are also found useful additives

21 Soil- Bituminous Stabilization
The Basic Principles of this stabilization are Water Proofing and Binding By Water Proofing inherent strength and other properties could be retained Most Commonly used materials are Cutback and Emulsion Bitumen Stabilized layer may be used as Sub-base or base course for all the roads

22 Factors affecting properties of soil-bitumen
The particle size, shape and gradation of the soil influence the properties of the soil-bitumen mix. Types of Bitumen Cutbacks of higher grade should be preferred Emulsions generally gives slightly inferior results than Cutback.

23 Amount of Mixing Mixing
Increasing proportion of bitumen causes a decrease in dry density but increases the stability after a certain bitumen content The optimum bitumen content for maximum stability generally ranges from 4 to 6% Mixing Improved type of mixing with low mixing period may be preferred

24 Compaction Effective Compaction results higher stability and resistance to absorb water Additives Anti stripping and reactive chemical additives have been tried to improve the properties of the mixes Portland cement can also be used along with the soil bitumen

25 Use of Locally Available Materials in Road Construction

26 Necessity Scarcity of good quality aggregates / soil for road construction Production and accumulation of different waste materials Disposal and environmental problem Economical and gainful utilisation

27 Limitations of Using Waste Materials
Quality of waste is not controlled by their manufacturers Characteristics of by-products vary in a wide range Road construction practice is accustomed to traditional materials of steady quality Specifications of layers compaction of traditional materials are not suitable for waste materials

28 General Criteria for Use of Waste Materials
Amount of yearly produced waste material should reach a certain lower limit The hauling distance should be acceptable The material should not have a poissonous effect The material should be insoluble in water The utilisation should not have a pollutional effect to the environment

29 Special Requirement for Using Waste Materials
Free from organic matter Should not swell or decay as influenced by water Should not be soluble in water Particles should be moderately porous

30 Industrial wastes Thermal Power Stations * Fly ash Steel Plants
* Bottom ash * Pond ash Steel Plants * Blast furnace slag * Granulated blast furnace slag * Steel slag

31 Utilisation of fly ash Thermal power - Major role in power generation
Indian scenario - Use of coal with high ash content - Negligible utilisation of ash produced Bulk utilisation - Civil engineering applications like construction of roads & embankments

32 Utilisation of fly ash Can be used for construction of
Embankments and backfills Stabilisation of subgrade and sub-base Rigid and semi-rigid pavements Fly ash properties vary widely, to be characterised before use Major constituents - oxides of silica, aluminum, iron, calcium & magnesium Environmentally safe material for road construction Possesses many favourable properties for embankment & road construction

33 Favourable properties of fly ash
Light weight, lesser pressure on sub-soil High shear strength Coarser ashes have high CBR value Pozzolanic nature, additional strength due to self-hardening Amenable to stabilisation Ease of compaction High permeability Non plastic Faster rate of consolidation and low compressibility Can be compacted using vibratory or static roller

34 Engineering properties of fly ash
Parameter Range Specific Gravity 1.90 – 2.55 Plasticity Non plastic Maximum dry density (gm/cc) 0.9 – 1.6 Optimum moisture content (%) 38.0 – 18.0 Cohesion (kN/m2) Negligible Angle of internal friction (j) 300 – 400 Coefficient of consolidation Cv (cm2/sec) 1.75 x 10-5 – 2.01 x 10-3 Compression index Cc 0.05 – 0.4 Permeability (cm/sec) 8 x 10-6 – 7 x 10-4 Particle size distribution (% of materials) Clay size fraction Silt size fraction Sand size fraction Gravel size fraction 1 – 10 8 – 85 7 – 90 0 – 10 Coefficient of uniformity 3.1 – 10.7

35 Differences between Indian & US fly ashes
Property compared Indian fly ash US fly ash Loss on ignition (Unburnt carbon) Less than 2 per cent 5 to 8 per cent SO3 content 0.1 to 0.2 per cent 3 to 4 per cent CaO content 1 to 3 per cent Increase in concentration of heavy metals 3 to 4 times in comparison to source coal 10 times or more in comparison to source coal Rate of leaching Lower Higher

36 Fly ash for road embankment
Ideally suited as backfill material for urban/ industrial areas and areas with weak sub soils Higher shear strength leads to greater stability Design is similar to earth embankments Intermediate soil layers for ease of construction and to provide confinement Side slope erosion needs to be controlled by providing soil cover Can be compacted under inclement weather conditions 15 to 20 per cent savings in construction cost depending on lead distance

37 Fly ash for road embankment
Typical cross section of fly ash road embankment

38 Approach embankment for second Nizamuddin bridge at Delhi
Length of embankment km Height varies from 6 to 9 m Ash utilised - 1,50,000 cubic metre Embankment opened to traffic in 1998 Instrumentation installed in the embankment showed very good performance Approximate savings due to usage of fly ash is about Rs.1.00 Crore

39 Approach embankment for second Nizamuddin bridge at Delhi

40 Second Nizamuddin bridge approach embankment
Spreading of pond ash Second Nizamuddin bridge approach embankment Compaction of pond ash

41 Second Nizamuddin bridge approach embankment
Stone pitching for slope protection Second Nizamuddin bridge approach embankment Traffic plying on the embankment

42 Utilisation of fly ash Four laning work on NH-6 (Dankuni to Kolaghat)
Length of stretch – 54 km Height of embankment – 3 to 4 m Fly ash utilisation – 2 Million cubic metres Water logged area (soft ground conditions) Compaction of fly ash over layer of geotextile

43 Reinforced fly ash embankment
Fly ash - better backfill material for reinforced embankments Polymeric reinforcing materials – Geogrids, friction ties, geotextiles Construction sequence – similar to reinforced earth structures

44 Okhla flyover approach embankment
First geogrid reinforced fly ash approach embankment constructed in the country Length of embankment – 59 m Height varied from 5.9 to 7.8 m Ash utilised – 2,700 cubic metre Opened to traffic in 1996 Performance has been very good

45 Okhla flyover approach embankment
7.8 to 5.9 m Facing panels Filter medium Geogrids Reinforced foundation mattress of bottom ash

46 Okhla flyover approach embankment
Erection of facing panels Okhla flyover approach embankment Rolling of pond ash

47 Okhla flyover approach embankment
Support provided to facing panels during construction Okhla flyover approach embankment Laying of geogrids

48 Hanuman Setu flyover approach embankment
Geogrid reinforced fly ash approach embankment Length of embankment – m Height varied from 3.42 m to 1.0 m Opened to traffic in 1997

49 Sarita Vihar flyover approach embankment
Length of embankment – 90 m Maximum height – 5.25 m Embankment opened to traffic in Feb 2001 Polymeric friction ties used for reinforcement

50 Sarita Vihar flyover reinforced approach embankment
Laying of friction ties Sarita Vihar flyover reinforced approach embankment Arrangement of friction ties before laying pond ash

51 Sarita Vihar flyover reinforced approach embankment
Compaction of pond ash using static and vibratory rollers Sarita Vihar flyover reinforced approach embankment Compaction using plate vibrator near the facing panels

52 Fly ash for road construction
Stabilised soil subgrade & sub-base/base courses Mixing with soil reduces plasticity characteristics of subgrade Addition of small percentage of lime or cement greatly improves strength Leaching of lime is inhibited and durability improves due to addition of fly ash Pond ash & bottom ash can also be stabilised Lime-fly ash mixture is better alternative to moorum for construction of WBM / WMM

53 Fly ash for road construction
Construction of semi-rigid/ rigid pavements Lime-fly ash concrete Dry lean cement fly ash concrete Roller compacted concrete Fly ash admixed concrete pavements Lime-fly ash bound macadam Precast block paving High performance concrete

54 Typical cross section of flexible pavement – conventional section
WBM Gr II/WMM 150 mm WBM Gr III/WMM 75 mm GSB 350 mm BM 75 mm DBM 100 mm Bituminous concrete 40 mm Typical cross section of flexible pavement – conventional section

55 Typical cross section of flexible pavement – using fly ash
WBM Gr III/WMM 75 mm Pond ash 350 mm BM 75 mm DBM 100 mm Bituminous concrete 40 mm Fly ash + 6% cement stabilised layer 150 mm Typical cross section of flexible pavement – using fly ash

56 Typical cross section of rigid pavement – using fly ash
Fly ash admixed PQC 300 mm DLFC 100 mm Pond ash 300 mm Typical cross section of rigid pavement – using fly ash

57 Demonstration road project at Raichur
Total length of the road – 1 km Five sections of 200 m each with different pavement sections Pond ash has been used for replacing moorum in sub-base course Stabilised pond ash used for replacing part of WBM layer One rigid pavement section using DLFC and RCCP technology was laid Performance of all the specifications is good

58 Demonstration road project using fly ash at Raichur
Mixing of lime stabilised pond ash Demonstration road project using fly ash at Raichur Compaction of stabilised pond ash using road roller

59 Demonstration road project using fly ash at Raichur
Construction of roller compacted concrete pavement Demonstration road project using fly ash at Raichur View of the demonstration road stretch after three years

60 Demonstration road project using fly ash near Dadri (U.P)
A rural road near Dadri in District Gautam Budh Nagar, Uttar Pradesh was selected Total length of road – 1.4 km Bottom ash used as embankment fill Base course constructed using fly ash stabilised with 8% cement RCCP Wearing course – 10 cm thickness RCCP Mix proportion – 1:2:4 30 per cent of cement and 20 per cent of sand replaced with fly ash in RCCP Shoulders – 8% cement stabilised fly ash Construction of Salarpur-Dadupur Rural Link Road Using Fly ash This project was taken up as part of an initiative supported by Canadian International Development Agency (CIDA) on thermal power plant ash utilisation. In this demonstration project it was decided to use bottom ash as a substitute for soil in the embankment. Bottom ash was covered with 30 cm thick soil layer to protect it from erosion. 8 per cent cement stabilised fly ash was provided as base course. Roller Compacted Concrete Pavement (RCCP) was adopted as wearing course. The mix proportion of RCCP adopted was 1:2:4. In RCCP, 30 per cent of cement and 20 per cent of fine aggregate (sand) was replaced with dry fly ash.

61 Stabilised fly ash base - 0.1 m Stabilised fly ash Shoulder
Demonstration road project using fly ash near Dadri (U.P) – Typical section Bottom ash RCCP wearing course m Stabilised fly ash base m Stabilised fly ash Shoulder Soil cover Normally the thickness of RCC pavement required for such rural roads would be about 23 cm. However based on earlier experience and due to limited finances available, it was decided to provide only 10 cm compacted thickness of RCC wearing course. Keeping in view the fact that the link road is located in a remote area and only light traffic is expected to ply on the road (less than 15 CVD), the pavement is expected to provide satisfactory service. Shoulders of 0.5 m width were provided on either side of the pavement. The shoulders were constructed using 8 % cement stabilised fly ash for a compacted thickness of 0.1 m.

62 Demonstration road project using fly ash near Dadri (U.P)
Stabilised base course The construction work of the demonstration stretch was taken up under the supervision of CRRI. Spreading of the embankment fill, stabilised mix and laying of RCC were carried out manually. Compaction was carried out using 8 ton static road roller. Concrete and stabilised fly ash mixing was carried out using diesel operated concrete mixer. The construction work was taken up in March 2002 and completed in about 60 days. Compaction of RCCP Mixing & laying of RCCP

63 IRC Guidelines / Specifications
Guidelines available on pavement construction IRC 60 ‘Tentative guidelines for use of lime fly ash concrete as pavement base or sub-base’ IRC 68 ‘Tentative guidelines on cement fly ash concrete for rigid pavement construction’ IRC 74 ‘Tentative guidelines for lean cement concrete and lean cement fly ash concrete as a pavement base or sub-base’ IRC 88 ‘Recommended practice for lime fly ash stabilised soil as base or sub-base in pavement construction’

64 Guidelines for use of fly ash in road embankments
Published recently by Indian Roads Congress (SP- 58:2001) Includes design aspects also Handling and construction Loose layer thickness of 400 mm can be adopted if vibratory rollers are used Moisture content - OMC + 2 per cent Use of vibratory rollers advocated Minimum dry density to be achieved - 95 per cent of modified Proctor density Ash layer and side soil cover to be constructed simultaneously

65 Utilisation of steel slags
Total production of slag from steel industries is about 8.0 million tonnes Types of slags Blast furnace slag Granulated blast furnace slag (GBFS) Air cooled slag Steel slag

66 Granulated blast furnace slag
Contains reactive silica Suitable for lime / cement stabilisation Air cooled blast furnace slag Non – reactive Suitable for use as coarse aggregates

67 CRRI work on utilisation of steel slags
Characterisation of slags produced at different steel plants Laboratory studies on Lime-GBFS mixes Semi-field studies on Lime-GBFS concrete Test track studies on usage of slags in road works

68 Properties of air cooled slag
Property Durgapur Bhilai Rourkela Delhi Quartzite Specification requirements Specific gravity 2.78 – 2.82 2.82 – 3.33 2.97 – 2.99 2.67 - Water absorption (%) 1.53 – 1.72 0.58 – 1.38 0.74 – 1.29 0.48 2% Max Los Angeles abrasion value (%) 18.80 25.00 14.28 34.00 40% Max Impact value (%) 15.79 14.80 16.90 24.50 30% Max Soundness value (%) 1.66 1.17 0.33 0.17 12% Max Percentage voids 46.40 43.90 43.10 43.80

69 Steel slags Obtained as a waste product during production of steel
Particle size varies from 80 mm to 300 microns Compared to blast furnace slag, steel slag contains lower amount of silica, higher amounts of iron oxide and calcium oxide Due to presence of free lime, steel slag should be weathered before using it in construction

70 Road projects executed under CRRI guidance using slags
Plant roads at Visakhapatnam Test tracks in collaboration with AP PWD using slags from Visakhapatnam Steel Plant Test tracks in collaboration with Orissa PWD using slags from Rourkella Plant Test tracks at R&D Centre for Iron & Steel, Ranchi using Slags from Bokaro Plant

71 Construction of test track using slag at Orissa
Labour based techniques for construction of stabilised layer

72 Lime stabilisation of iron slags (Orissa)
View of finished surface of road constructed using slags at Orissa

73 Processed municipal wastes
Processed municipal wastes utilised for construction of test track on village road near Delhi Stabilised municipal waste used for construction of sub-base layer Performance of stretch is good

74 Kimberlite tailings Kimberlite tailings are waste produced from diamond mining Can be used in base or sub-base course by adopting mechanical or cement stabilisation High value of water absorption makes them unsuitable for use in bituminous pavement

75 THANK YOU


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