Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
CHAPTER - 1 INTRODUCTION 1.0 GENERAL 1.1 Pavement: That with which anything is paved; a floor or covering of solid material, laid so as to make a hard and convenient surface for travel; a paved road or sidewalk; a decorative interior floor of tiles colored bricks.
1.2 Types of pavement: Pavements are typically divided into the following three general categories: 1) Flexible
2) Rigid
and
3) Unpaved (gravel or dirt).
1.2 .1 F lexible (Bituminous Pavements): Flexible pavements are constructed of several layers of natural granular material covered with one or more waterproof bituminous surface layers, and as the name imply, are considered to be flexible. A flexible pavement will flex (bend) under the load of a tires. The objective with the design of a flexible pavement is to avoid the excessive flexing of any layer, failure to achieve this will result in the over stressing of a layer, which ultimately will cause the pavement to fail. In flexible pavements, the load distribution pattern changes from one layer to another, because the strength of each layer is different. The strongest material (least flexible) is in the top layer and the weakest material (most flexible) is in the lowest layer. The reason for this is that at the surface the wheel load is applied to a small area, the result is high stress levels, deeper down in the pavement, the wheel load is applied to larger area, and the result is lower stress levels thus enabling the use of weaker materials.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
Fig – 1.1 Load distribution of flexible pavement
1.2 .2 Rig id (Concrete) Pavements: Rigid pavements are composed of a PCC surface course. Such pavements are substantially “stiffer” than flexible pavements due to the high modulus of elasticity of thematerial. PCC Further, these pavements can have reinforcing steel, which is generally used to reduce or eliminate joints. The increased rigidity of concrete allows the concrete surface layer to bridge small weak areas in the supporting layer through what is known as beam action. This allows the placement of rigid pavements on relatively weak supporting layers, as long as the supporting layer material particles will not be carried away by water forced up by the pumping action of wheel loads.
Fig - 1.2 Load distribution of rigid pavement
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
1.3 PAVEMENT FUNCTIONS: The primary functions of a pavement are to:
Provide a reaso nably smooth riding surface: A smooth riding surface (Low Roughness) is essential for riding comfort, and over the years it has become the measure of how road users perceive a road. Roughness can arise from a number of causes, most often however it is from pavement distress due to structural deformation.
Provide a dequate surface friction (skid resis tance): In addition to a riding comfort, the other road user requirement is that of safety. Safety, especially during wet conditions can be linked to a loss of surface friction between the tyre and the pavement surface. A pavement must therefore provide sufficient surface friction and texture to ensu re road user safety under allconditio ns.
Protect the sub g rade: The supporting soil beneath the pavement is commonly referred to as the sub grade, should it be over-stressed by the applied axle loads it will deform and lose its ability to properly support these axle loads. Therefore, the pavement must have sufficient structural capacity (strength and thickness) to adequately reduce the actual stresses so that they do not exceed the strength of the sub grade. The strength and thickness requirements of a pavement can vary greatly depending on the combination of sub grade type and loading conditio n (magnitude and number of axle loads).
Provide waterproofing: The pavement surfacing acts as a waterproofing surface that prevents the under laying support layers including the sub grade from becoming saturated through moisture ingress. When saturated, soil loses its ability to adequately support the applied axle loads, which will lead to premature failure of the pavement.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
1.4 FACTORS INF LUENCING THE P ERFORMANCE OF A PAVEMENT 1.4 .1 Traffic: Traffic
is
the
most
important
factor
influencing
pavement
performance.
The
performance of pavements is mostly influenced by the loading magnitude, configuration and the number of load repetitions by heavy vehicles. The damage caused per pass to a pavement by an axle is defined relative to the damage per pass of a standard axle load, which is defined as an 80 KN single axle load. Thus a pavement is designed to withstand a certain number of standard axle load repetitions (E80’s) that will esult r in a certain terminal condition of deterioration.
1.4.2 Moisture (water): Moisture can significantly weaken the support strength of natural gravel materials, especially the sub grade. Moisture can enter the pavement structure through cracks and holes in the surface, laterally through the sub grade, and from the underlying water table through capillary action. The result of moisture ingress is the lubrication of particles, loss of particle interlock and subsequent particle displacement resulting in pavement failure.
1.4 .3 Sub grade: The sub grade is the underlying soil that supports the applied wheel loads. If the sub grade is too weak to support the wheel loads, the pavement will flex excessively which ultimately causes the pavement to fail. If natural variations in the composition of the sub grade are not adequately addressed by the pavement design, significant differences in pavement performance will be experienced
.
1.4 .4 Construction quality: Failure
to
obtain
proper
compaction,
improper
moisture
conditions
during
construction, quality of materials, and accurate layer thickness (after compaction) all directly affect the performance of a pavement. These conditions stress the need for skilled staff and the importance of good inspection and quality control procedures during construction.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
1.5 NEED F OR STUDY: It is evident from the present scenario that highways are deteriorating and the increasing cost of pavement construction also the construction of roads on a weak sub grade soil is a major challenge to the highways engineers to construct a stabilized pavement for heavy wheel load configuration. There is a need to find out some alternative to materials to improve the stabilization point of view of the roads. Any material which contains the silicon and aluminum in amorphous state can be a source of binding, stabilizing and improving performance of the pavement where Geo grid adds to an added advantage for its improving its strength. Fly ash, GGBS, Quarry dust which contains this are considered to be waste product. They are produced abundantly in India and hence can be utilized. An effort has been made in this study to investigate the influence of these above products for study of the pavement.
1.6 OB JECT IVE OF STUDY: The objectives of this experimental study are:
To explore the possibility of using locally available materials and by using Geo grid, Fly ash, GGBS, Quarry dust in various proportions to get the best combination for the performance of pavement.
To design the flexible pavement for the best combination of proportion obtained which yields the best strength for pavement.
To match the CBR of red soil with the CBR of black cotton soil with the various proportions of above mentioned materials.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
1.7 S COPE OF WORK: The experimental investigations on the properties of red soil and black cotton soil for different combination of Fly ash, GGBS and Quarry dust are undertaken. The test procedures currently available for normal soil have been used. Fly-Ash (Class F) from Raichur thermal plant & GGBS from Bellary Jindal Steel Plant were considered as the source materials. The interpretation of the data and the analysis are on similar lines to the standard tests conducted on the soil such as, Specific gravity, Moisture content, Plastic limit, Liquid limit, Modified Proctor test, CBR test.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
CHAPTER – 2 LITERATURE REVIEW 2.1 INTRODUCTION This chapter presents an overall background on the current knowledge in the field of highway construction. Emphasis is on the more recent works with respect to use of Fly ash, Ground granulated blast furnace slag, Quarry dust and Geo grids which help us to have better evaluation of weak sub grade soil and improving subsequent layers of the pavement by using advanced stabilizat ion techniques.
2.2 STABIZATION MATER IALS 2.2 .1 FLY ASH Fly ash by itself has little cementatious value but in the presence of moisture it reacts chemically and forms cementatious compounds and attributes to the improvement of strength and compressibility characteristics of soils. It has a long history of use as an engineering material and has been successfully employed in geotechnical applications. Pandianet.al. (2002), Studied the effect of two types of fly ashes Raichur fly ash (Class F)
and Neyveli fly ash (Class C) on the CBR characteristics of the black cotton soil. The fly ash content was increased from 0 to 100%. Generally the CBR/strength is contributed by its cohesion and friction. TheCBR of BC soil, which consists of predominantly of finer particles, is contributed by cohesion. The CBR of fly ash, which consists predominantly of coarser particles, is contributed by its frictional component. The low CBR of BC soil is attributed to the inherent low strength, which is due to dominance the of clay fraction. The addition of fly ash to BC soil increases the CBR of the mix up tofirst the optimum level due to the frictional resistance from fly ash in addition to the cohesion from BC Further soil. addition of fly ash beyond the optimum level causes a decrease up to 60% and then up to th e Second optimum level there is an increase. Thus the variation of CBR of fly ash-BC soil mixes can be attributed to the relative contribution of frictional or cohesive resistance from Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique fly ash or BC soil, respectively. In Neyveli fly ash also there is an increase of strength with the increase in the fly ash content, here there will be additional puzzolonic reaction forming cementitious compounds resulting in good binding between BC soil and fly ash particles.
2.2 .2 GR OUND GRANULATED BLAST F URNANCE S LAG The hydraulic potential of blast furnace slag was first discovered in Germany in 1862. In 1865, lime-activated blast furnace slag started to be produced commercially in Germany and in 1880 GGBS was first used in combination with Portland cement (Concrete Society, 1991). In Europe, GGBS has been used for over 100 years. In North America, the history of the use of GGBS in quality concrete dates back about 50 years (Yazdani, 2002). In Southeast Asian countries including Mainland China and Hong Kong, GGBS was used in concrete in around 1990. Between 1955 and 1995, about 1.1 billion tonnes of cement was produced in Germany, about 150 million tonnes of which consisted of blast furnace slag (Geiseler et al, 1995). In China, the estimated total GGBS production was about 100 million tonnes in 2007 (Chen, 2006). It has major applications in soil stabilization and improves the properties of the soil.
2.2 .3 QUARRY DUST Construction of pavements in expansive soil areas creates a lot of problems for civil engineers because of its low California bearing ratio (CBR) value and alternate swell-shrink behavior when the soil comes in contact with water. This results not only in high cost of construction but also necessitate frequent repairing as cracks of different shapes and varying depth are seen on these soils .There are different techniques to increase the CBR value and to reduce the swelling pressure of soil. Stabilization using industrial wastes is one of them. Stabilization of expansive soil has been done by addition of different types of industrial waste. Quarry dust is another industrial wastes produced as by product during crushing of large size stones in crusher units during production of coarse aggregates. Quarry dust has been added to expansive soil alone (Gupta et al., 2002) or in combination with lime (Sabat and Das 2009; Sabat, 2012) of r stabilization purposes.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
2.2.4 GEO GRID The first, and srcinal, geogrids (called unitized or homogeneous types, or more commonly referred to as 'punched and drawn geogrids') were invented Dr by Frank Brian Mercer in theUnited Kingdomat Netlon, Ltd., and were brought in 1982 to North America by the Tensar Corporation. A conference in 1984 was helpful in bringing geogrids to the engineering design community. A similar type of drawn geogrid which srcinated n Italyby i Tenax is also available, as are products by new manufacturers in Asia. The second category of geogrids are more flexible, textile-like geogrids using bundles of polyethylene-c oated polyester fib ers
as
the
reinforcing
component.
They
were
first
developed by ICI Linear Composites LTD in the United Kingdom around 1980. This led to the development of polyester yarn geogrids made on textile weaving machinery. In this process hundreds of continuous fibers are gathered together to form yarns which are woven into longitudinal and transverse ribs with large open spaces between. The cross-over are joined by knitting or intertwining before the entire unit is protected by a subsequent coating.Bitumen, atex, l
or PVC is
the
usual
coating
material s. Geosynthetics within this
group are manufactured by many companies having various trademarked products. There are possibly as many as 25 companies manufacturing coated yarn-type polyester geogrids on a worldwide basis . The third categories of geogrids are made by laser or ultrasonically bonding together polyester or polypropylene rods or straps in a grid like pattern. Two manufacturers currently make such geogrids.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
CHAPTER – 3 MATERIAL USED FOR SOIL STABILIZAT ION 3. 1 FLY ASH i and Fly ash, also known as flue-ash, is one of the residues generatedn combustion, comprises thefine particles that rise with theflue gases. Ash which does not rise is termed bottom ash. In an industrial context, fly ash usually refers to ash produced during combustion ofcoal. Fly ash is generally captured ybelectrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys of coal-fired power plants, and together withbottom ash removed from the bottom of the furnace is in this case jointly known as coal ash. Depending upon the source and makeup of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts ofsilicon
dioxide (SiO2 )
(both amorphousand crystalline) and calcium
oxide( CaO),
both
being endemic ingredients in many coal-bearing rock strata. Toxic constituents depend upon the specific coal bed makeup, but may include one or more of the following elements or substances found in trace quanti ties (up to hundreds ppm): arsenic, beryllium, boron, cadmium, chromium, chromium, cobalt, lead,manganese, mercury, molybdenum, selenium, strontium, thallium and vanadium, along with dioxins and PAH compounds
3.1 .1 CLASS F FLY ASH The burning of harder,
older
anthracite
and
bituminous coal typically produces Class F fly ash. This fly ash
ispozzolanic ni
20% lime C ( aO).
nature,
Possessing
and
contains
pozzolanic
less
properties,
than the
glassy silica and alumina of Class F fly ash requires a cementing agent, such as Portland cement, quicklime, or hydrated lime, with the presence of water in order to react and produce cementitious compounds. Alternatively the addition of a chemical activator such as sodium silicate(water glass) to a Class F ash can lead to the formation of a geopolymer.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
3.1 .2 SOIL STABILIZATION Soil stabilization is the permanent physical and chemical alteration of soils to enhance their physical properties. Stabilization can increase the shear strength of a soil and/or control the shrink-swell properties of a soil, thus improving the load-bearing capacity of a sub-grade to support pavements and foundations. Stabilization can be used to treat a wide range of subgrade materials from expansive clays to granular materials. Stabilization can be achieved with a variety of chemical additives including lime, fly ash, and Portland cement. Proper design and testing is an important component of any stabilization project. This allows for the establishment of design criteria as well as the determination of the proper chemical additive and admixture rate to be used to achieve the desired engineering properties. Benefits of the stabilization process can include: Higher resistance (R) values, Reduction in plasticity, Lower permeability, Reduction of pavement thickness, Elimination of excavation - material hauling/handling -and base importation, Aids compaction, Provides -weather” “all access onto and within projects sites. Another form of soil treatment closely related to soil stabilization is soil modification, sometim es referred to as “mud drying” or soil conditioning. Although some stabilization inherently occurs in soil modification, the distinction is that soil modification is merely a means to reduce the moisture content of a soil to expedite construction, whereas stabilization can substantially increase the shear strength of a material such that it can be incorporated into the project’s structural design. The determining factors associated with soil modification vs soil stabilization may be the existing moisture content, the end use of the soil structure and ultimately the cost benefit provided. Equipment for the stabilization and modification processes include: chemical additive spreaders, soil mixers (reclaimers), portable pneumatic storage containers, water trucks, deep lift compactors, motor graders.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
3.2 GROUND GRANULATED BLAST FURNANCE SLAG Ground-granulated blast-furnace slag (GGBS or GGBFS) is obtained by quenching molten ironslag (a by-product of iron and steel-making) fromblast a furnace in water or steam, to produce aglassy, granula r product that si then dried and ground into a fine powder.
3.2.1 PRODUCTION AND CHEMICAL COMPOSITION The
chemical
composition
of
a
slag
varies
considerably
depending
on
the
composition of the raw materials in e th iron productionprocess. Silicate and aluminate impurities from the ore and coke are combined in th e blast furnace with a fluxwhich lowers the viscosity o f the slag. In the case of gpiiron productionthe flux consists mostly of a mixture of limestone andforsterite or in some casesdolomite. In theblast furnace the slag floats on top of th e iron and is decanted for separation. Slow cooling of slag melts results in an unreactive crystalline material consisting of an assemblage of Ca-Al-Mg silicates. To obtain a good slag reactivity or hydraulicity, the slag melt needs to be rapidly cooled or quenched below 800 °C in order to prevent the crystallization of merwiniteand melilite.To cool and fragment the slag a granulation process can be applied in which molten slag is subjected to jet streams of water or air under pressure. Alternatively, in the pelletization process the liquid slag is partially cooled with water and subsequently projected into the air by a rotating drum. In order to obtain a suitable reactivity, the obtained fragments are ground to reach the same ineness f asPortland cement. The main components of blast furnace slag are CaO (30-50%), SiO 2 (28-38%), Al2 O 3 (8-24%), and MgO (1-18%). In general increasing the CaO content of the slag results in raised slagbasicity and an increase in compressive strength. The MgO and Al2 O3 content show the same trend up to respectively 10-12% and 14%, beyond which no further improvement can be obtained. Several compositional ratios or so-called hydraulic indices have been used to correlate slag composition hwit hydraulic activity; the latter being mostly expressed as the bindercompressive strength.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
3.2 .2 SOIL STABILIZATION Soil stabilization is widely used ni connection with road, pavement and of undation constructio n. It improves the engineering properties of the soil, e.g.: • Strength - to increase the strength and bearing capacity, • Volume stability - to control the swell-shrink characteristics caused by moisture changes, • Durability - to increase the resistance to erosion, weathering or traffic loading. Normally, lime or cement (or acombination) is used for soil stabilization.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
3.3 QUARRY DUST The technique of soil stabilization is usually adopted with the purpose of rendering plastic soils coherent to the standards and requirements of engineering Projects. A variety of ground improvement technique have been developed and successfully applied in several areas. The selection of appropriate ground improvement technique depends on the soil that is to be treated, the availability of materials required and economic viability. All the techniques basically involve introduction of different material in the soil deposit. Quarry dust/crusher dust is obtained as soil solid wastes during crushing of stones to obtain aggregates. Now a day’s different types of materials like lime, cement, fly ash etc. are used. Quarry dust exhibits high shear strength which is highly beneficial for its use as a geotechnical material Soosan et al. (2001a). It has a good permeability and variation in water content does not seriously affect its desirable properties. Quarry dust can be used as a substitute for sand to improve the properties of lateritic soil Soosan et al. (2001b). Sridharan et al. (2005), conducted studies on the effect of quarry dust on the geotechnical properties of soil used in highway construction and concluded that the CBR value steadily increased with increase in percentage of quarry dust. And the improvement in CBR value can be contributed to the significant improvement in angle of shearing resistance. Higher CBR values of soil-quarry dust mixes enhance their potential for use as a sub base for flexib le pavement.
3.3.1 SOIL STABILIZATION The use of quarry dust si to ensure economic stabilization of soil and also used under flexible pavements to increase the o l ad carrying capacity of the pavement by distributing the load through a finite thickness pavement Eze-Uzoamaka and Agbo (2010). The quarry dust can be used to know the compressive and tensile strength of the stabilized soil. The effect of quarry dust on th e stability of soil aggregate mix used in a base course and summarizes that the quality of quarry dusts in a soil aggregate mix has a major influence on maximum density, strength, frost resistance and drainage.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
3.4 GEO GRID A geogrid is geosynthetic m aterial
used
to
reinforce
soils
and
similar
materials.
Geogrids are commonly used to reinforce retaining walls , as well as sub bases or subsoil’s below roads or structures. Soils pull apart under tension. Compared to soil, geogrids are strong in tension. This fact allows them to transfer forces to a larger area of soil than would otherwise be the case. Geogrids are commonly made polymermaterials, such aspolyester, polyethylene or polypropylene. They may be woven or knitted from yarns, heat-welded from strips of material or produced by punching a regular pattern of holes in sheets of material, then stretched into a grid . The development of methods of preparing relatively rigidpolymeric materials
by tensile drawing,[1] in a sense "cold
working," raised the possibility that such materials could be used
in
the
reinforcement
of
soils
for
walls, steep
slopes,roadway bases and foundation o s ils. Used as such, the major function of the resulting geogrids is in the area of reinforcement. This area, as with many othergeosynthetics,
Fig 3.4 Geogrid
is very active, with anumber of different products, materials, configurations, etc., making up today's geogrid market. The key feature of all geogrids is that the openings between the adjacent sets of longitudinal and transverse ribs, called “apertures,” are large enough toallow for soil strike-through from one side of the geogrid to the other. The ribs of some geogrids are often quite stiff compared to thefibers ofgeotextiles. As discussed later, not only si rib strength important, but junctio n strength is al so important. The reason for this is that in anchorage situations the soil strike-through within the apertures bears against the transverse ribs, which transmits the load to the longit udinal ribs via the junctio ns. The junctions are, of course, where the ongitudinal l and transverse ribs meet and are connected. They are sometimes called “nodes”.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
3.4.1 HOW DO GEOGRID WORK S? Geogrids
work
by
interlocking
with
the
granular or soil material placed over them. The apertures allow for strike-through of the cover soil material which then interlocks with the ribs (flat straps/bars) providing confinement of the overlaying granular/soil material due to the stiffness and strength of the ribs as shown in figures.
Fig 3.4.1.1
3.4.2 WHERE ARE GEOGRID USED? There are several major markets for geogrids. These are base reinforcement, earth retaining
wall
construction
including
veneer
stabilization,
the
segmental
retaining
wall
market, embankment reinforcement and pile cap platforms. Biaxial geogrids are primarily used in base reinforcement applications, while the uniaxial geogrids are often used in the other markets. This document will only be concentrating on base reinforcement and biaxial geogrids. The base reinforcement market is just what the name implies. These are applications where an engineer is trying to improve the performance of a gravel base over poor soils, trying to minimize the amount of gravel in the base course design, or increasing the life of the surface cover, concrete or asphalt. Geogrids are used under parking lots, airport runways, gravel construction roads, highways, dam levees and railroad tracks.
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
CHAPTER – 4 EXPERIMENTAL INVESTIGATIONS 4.1 GENERAL This chapter includes the experimental investigation carried out to study the different properties of Red soil and Black cotton soil. The various tests which are been carried out are being explained in this chapter. This chapter also includes the effect of different materials used during the experimental investigation on properties of soil and also the details about testing procedures of different tests performed during the investigation.
The Red soil and Black cotton soil used throughout the project for the different tests was procured from Kineye, Belgaum (Goa – Belgaum Highway). The tests listed below where carried out in Jain College of Engineering, Belgaum at their Geo-technical Laboratory and CBR tests where been carried out and Gogte Institute of Technology, Belgaum at their Geo – technical Laboratory.
4.2 TESTS CONDUCTED The different tests which were conducted are as listed below: 4.2.1 SPECIFIC GRAVITY The specific gravity of a substance is the ratio of the unit weight of the substance to the unit weight of water. Specific gravity of a soil is the measure of its strength or quality of the material. Soils having low specific gravity are generally weak in strength. Specific gravity is defined as the ratio of the mass of a given volume of soil sample to the mass of an equal volume of water at the same temperature. FORMULATION
Specific Gravity =
=(
) ()
…4.2.1
Where, W1 –Empty weight of density bottle rd W2 – Wt 1/3of Soil and bottle
Dept. of C ivil Engineering, JCE, Belgaum
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– Wt of Fully filled water in density bottle Page 17
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique 4.2.2 MOISTURE CONTENT
Moisture content of soil is nothing but to determine the water content of soil sample by oven drying method. The experiment forms an essential part of any other laboratory experiments. FORMULATION
Moisture content =
………..4.2.2
where, W1 – Wt of container W2 – Wt of Wet Soil + container W2 – Wt of Dry Soil + container
4.2.3 LIQUID LIMIT
The liquid limit is determined in the laboratory with the help of the standard liquid limit apparatus designed by Casagrande. Liquid limit is the water content corresponding to arbitrary limit between liquid limit and plastic limit of consistency of a soil. It is defined as the minimum water content at which the soil is still in liquid state, but has a small shearing strength against flowing. It is also defined as the minimum water content at which apart of soil cut by a groove of standard dimensions, will flow together for a distance of 12mm under an impact of 25 blows in the casagrande device. The tested sample is oven dried for 24 hrs to get moisture content. FORMULATION
Moisture content =
…….4.2.3
where, W1 – Wt of container W2 – Wt of Wet Soil + container W2 – Wt of Dry Soil + container
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique 4.2.4 PLASTIC LIMIT
Plastic limit is the water content corresponding to an arbitrary limit between the plastic and the semi-solid states of consistency of a soil. It is defined as the minimum water content at which a soil just begins to crumble when rolled into a thread approximately 3mm in dia. The tested sample is oven dried for 24 rhs to get moisture content. FORMULATION
Moisture content =
…….4.2.4
where, W1 – Wt of container W2 – Wt of Wet Soil + container W2 – Wt of Dry Soil + container
4.2.5 MODIFIED PROCTOR COMPACTION TEST
Higher compaction is needed for heavier transport and military aircraft. The modified proctor test was developed to give a higher standard of compaction. In this test, the soil is compacted in standard proctor mould but in 5 layers, each layer being given 25 blows of a 4.5 kg hammer dropped through a height of 18 inches. The compactive energy given to the soil in this test is 27260 kg-cm per 1000 cm3 which is about 4.5 times the Standard Proctor test. The effect of higher compaction is to increase the maximum dry density and to decrease the optimum moisture content. FORMULATION
Bulk Density (γb ) = Dry Density (γd ) =
gm/cc……..4.2.5.1
gm/cc ……….4.2.5.2
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3 CALCULATIONS 4.3.1 RED SOIL Specific Gravity =
=
M oisture content =
Liquid limit
=
Plastic limit
=
=
= 2.180.
( )()
=
=
=
( )()
= 4.738
= 50 at 25 no. of blows.
= 26.92
Modified Proctor
Bulk Density (γb ) = = Dry density ( γd ) =
=
= 2.033
gm/cc gm/cc
= 1.69
gm/cc
Sl no.
Density Determination
12%
16%
20%
1
Wt. of mould + soil W1 grams
4385
4385
4385
2
Wt of empty mould W2 grams
6378
6502
6472
3
Wt of compacted soil W1-W2 grams
1993
2117
2087
4 5
Bulk Density γb gm/cc Dry Density γd 1.69
2.033 1.77
2.16 1.72
2.12
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.2 PROPERTIES OF THE RED SOIL A sample of 3 kg soil was taken for the test to be conducted, Table 4.3.2.1 Re sults of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.18
2
Moisture content
4.73%
3
Liquid limit
50%
4
Plastic limit
26.93%
5
Maximum dry density
1.775 gm/cc
6
Optimum moisture content
21.8%
RED SOIL 1.78
1.77 1.76
Y T I S N E D Y R D
1.75 1.74 1.73 1.72
red soil modified proctor
1.71 1.7
1.69 1.68
19
20
21
22
23
24
MOISTURE CONTENT
Fig 4.3.2.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 21
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.3 MIX-1 PROPERTIES OF THE RED SOIL WITH 5% GGBS , 10 %FLY ASH AND 10 % QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 10% Fly ash, 10% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.3.1 Re sults of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.58
2
Moisture content
5.69%
3
Liquid limit
41.13%
4
Plastic limit
29.85%
5
Maximum dry density
1.81 gm/cc
6
Optimum moisture content
19.8%
RED+5%GGBS+10%FLY ASH + 10% DUST 1.82
1.8 1.78 Y IT S N E D Y R D
1.76 1.74 RED+5%GGBS+10%FLY ASH + 10% DUST
1.72 1.7 1.68
1.66 17
18
19
20
21
MOISTURE CONTENT
Fig 4.3.3.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 22
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.4 MIX-2 PROPERT IES OF T HE RED SOIL WI TH 5% GGBS , 12 %FLY ASH AND 12 % QUARRY DUST A sample of 3 kg soil was taken forthe test tobe conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 12% Fly ash, 12% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.4.1 Re sults of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.21
2
Moisture content
4.3%
3
Liquid limit
41.79%
4
Plastic limit
29.60%
5
Maximum dry density
1.82 gm/cc
6
Optimum moisture content
18%
RED+5%GGBS+12%FLY ASH +12% DUST 1.84 1.82 1.8 Y IT S N E D Y R D
1.78 RED+5%GGBS+12%FLY ASH +12% DUST
1.76 1.74
1.72 1.7 0
10
20
30
MOISTURE CONTENT
Fig 4.3.4.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 23
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.5 MIX-3 PROPERT IES OF T HE RED SOIL WITH 5% GGBS , 14 %FLY ASH AND 14 % QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 14% Fly ash, 14% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.5.1 Re sults of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.56
2
Moisture content
4.53%
3
Liquid limit
36.49%
4
Plastic limit
21.62%
5
Maximum dry density
1.855 gm/cc
6
Optimum moisture content
17%
RED+5%GGBS+14%FLY A SH +14 % DUST 1.88 1.86 1.84 Y IT S N E D Y R D
1.82 1.8 RED+5%GGBS+14%FLY ASH +14% DUST
1.78
1.76 1.74 1.72
0
10
20
30
MOISTURE CONTENT
Fig 4.3.5.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 24
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.6 MIX-4 PROPERT IES OF T HE RED SOIL WI TH 5% GGBS , 16 %FLY ASH AND 16 % QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 10% Fly ash, 10% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.6.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.2
2
Moisture content
2.68%
3
Liquid limit
37.12%
4
Plastic limit
22.22%
5
Maximum dry density
1.805 gm/cc
6
Optimum moisture content
19%
RED+5%GGBS+16%FLY AS H +16% DUST 1.84 1.82 1.8 Y IT S N E D Y R D
1.78
1.76 1.74 RED+5%GGBS+16%FLY ASH +16% DUST
1.72
1.7 1.68 1.66 1.64
0
10
20
30
MOISTURE CONTENT
Fig 4.3.6.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 25
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.7 MIX-5 PROPERT IES OF T HE RED SOIL WITH 5% GGBS, 18%FLY ASH AND 18 % QUARRY DUST A sample of 3 kg soil was taken for the test to be conductedfor the particular mix. In this soil, a mix was prepared containing 5% GGBS, 18% Fly ash, 18% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.7.1 Results of different tes ts carrie d.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.06
2
Moisture content
2.53%
3
Liquid limit
38.56%
4
Plastic limit
27.37%
5
Maximum dry density
1.79 gm/cc
6
Optimum moisture content
21%
RED+5%GGBS+18%FLY AS H +18% DUST 1.8 1.78 1.76 Y IT S N E D Y R D
1.74 1.72 RED+5%GGBS+18%FLY ASH +18% DUST
1.7 1.68 1.66 1.64 0
5
10
15
20
25
MOISTURE CONTENT
Fig 4.3.7.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 26
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.8 MIX-6 PROPER TIES OF THE RED SOIL WITH 5% GGBS , 20 %FLY ASH AND 20 % QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 20% Fly ash, 20% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.8.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.34
2
Moisture content
2.15%
3
Liquid limit
38.93%
4
Plastic limit
16.9%
5
Maximum dry density
1.85 gm/cc
6
Optimum moisture content
17%
RED+5%GGBS+20%FLY AS H +20% DUST 1.86 1.84 1.82 Y IT S N E D Y R D
1.8 1.78 1.76
RED+5%GGBS+20%FLY ASH +20% DUST
1.74 1.72 1.7 1.68 0
10
20
30
MOISTURE CONTENT
Fig 4.3.8.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 27
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3 .9 PROP ERTIES OF THE BLACK COTT ON SOIL A sample of 3 kg soil was taken for the test to be conducted,As black cotton soil is expansive in nature it was necessary to conduct the following tests. Table 4.3.9.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.22
2
Moisture content
4.88%
3
Liquid limit
60.14%
4
Plastic limit
29.83%
5
Maximum dry density
1.55 gm/cc
6
Optimum moisture content
30%
BLACK COTTON 1.8 1.6 1.4
1.2 Y IT S N E D Y R D
1 0.8 black cotton
0.6 0.4 0.2 0 0
20
40
60
MOISTURE CONTENT
Fig 4.3.9.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 28
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.10 MIX-1 PROPERTIES OF THE BLACK COTTON SOIL WITH 5% GGBS, 10 %FLY ASH AND 10 % QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 10% Fly ash, 10% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.10.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.74
2
Moisture content
5.74%
3
Liquid limit
67.08%
4
Plastic limit
30.98%
5
Maximum dry density
1.68 gm/cc
6
Optimum moisture content
22%
BLACK+5%GGBS+10%FLY A SH + 1 0% DUST
1.7 1.68 1.66 Y IT S N E D Y R D
1.64 1.62 1.6
BLACK+5%GGBS+10%F LY ASH + 10% DUST
1.58 1.56 1.54 1.52 0
10
20
30
MOISTURE CONTENT
Fig 4.3.10.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 29
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.11 MIX-2 PROPERTIES OF THE BLACK COTTON SOIL WITH 5% GGBS, 12 %FLY ASH AND 12% QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 12% Fly ash, 12% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.11.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.18
2
Moisture content
6.8%
3
Liquid limit
58.04%
4
Plastic limit
33.84%
5
Maximum dry density
1.53 gm/cc
6
Optimum moisture content
26%
BLACK+5%GGBS+12%FLY A SH +12 % DUST
1.54
1.535 Y IT S N E D Y R D
1.53 BLACK+5%GGBS+12%F LY ASH +12% DUST
1.525
1.52
1.515
0
10
20
30
40
MOISTURE CONTENT
Fig 4.3.11.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 30
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.12 MIX-3 PROPERTIES OF THE BLACK COTTON SOIL WITH 5% GGBS, 14 %FLY ASH AND 14% QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 14% Fly ash, 14% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.12.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.17
2
Moisture content
4.83%
3
Liquid limit
67.94%
4
Plastic limit
28.07%
5
Maximum dry density
1.59 gm/cc
6
Optimum moisture content
25%
BLACK+5%GGBS+14%FLY A SH +14 % D UST 1.595
1.59 Y IT S N E D Y R D
1.585 BLACK+5%GGBS+14%FLY ASH +14% DUST
1.58
1.575 1.57
0
10
20
30
MOISTURE CONTENT
Fig 4.3.12.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 31
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.13 MIX-4 PROPERTIES OF THE BLACK COTTON SOIL WITH 5% GGBS, 16 %FLY ASH AND 16% QUARRY DUST A sample of 3 kg soil was taken for the testto be conducted for the particul ar mix. In this soil, a mix was prepared containing 5% GGBS, 16% Fly ash, 16% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.13.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
1.91
2
Moisture content
4.61%
3
Liquid limit
60.93%
4
Plastic limit
35%
5
Maximum dry density
1.57 gm/cc
6
Optimum moisture content
23%
BLACK+5%GGBS+16%FLY A SH +16% DUST
1.58 1.56 1.54 Y IT S N E D Y R D
1.52 BLACK+5%GGBS+16%FLY ASH +16% DUST
1.5 1.48
1.46 1.44 1.42 1.4 0
10
20
30
40
MOISTURE CONTENT
Fig 4.3.13.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 32
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.14 MIX-5 PROPERTIES OF THE BLACK COTTON SOIL WITH 5% GGBS, 18 %FLY ASH AND 18% QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 18% Fly ash, 18% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.14.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.65
2
Moisture content
3.77%
3
Liquid limit
59.19%
4
Plastic limit
39.85%
5
Maximum dry density
1.55 gm/cc
6
Optimum moisture content
26%
BLACK+5%GGBS+18%FLY A SH +18 % DUST 1.57
1.56 1.55 Y IT S N E D Y R D
1.54 1.53 1.52
BLACK+5%GGBS+18%FL Y ASH +18% DUST
1.51 1.5
1.49 1.48 1.47 1.46 0
10
20
30
40
MOISTURE CONTENT
Fig 4.3.14.1 M odified proctor compaction test
Dept. of C ivil Engineering, JCE, Belgaum
Page 33
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.3.15 MIX-6 PROPERTIES OF THE BLACK COTTON SOIL WITH 5% GGBS, 20 %FLY ASH AND 20% QUARRY DUST A sample of 3 kg soil was taken for the test to be conducted for the particular mix. In this soil, a mix was prepared containing 5% GGBS, 20% Fly ash, 20% quarry dust. The respective percentages are replaced with 3 kg of soil. Table 4.3.15.1 Results of different tes ts carried.
SERIAL NO.
TESTS
RESULT
1
Specific gravity
2.42
2
Moisture content
4.53%
3
Liquid limit
62.63%
4
Plastic limit
31.61%
5
Maximum dry density
1.627 gm/cc
6
Optimum moisture content
14%
BLACK+5%GGBS+20%FLY A SH +20% DUST 1.64 1.63 1.62 Y IT S N E D Y R D
1.61 1.6 BLACK+5%GGBS+20%F LY ASH +20% DUST
1.59 1.58
1.57 1.56 1.55
0
10
20
30
MOISTURE CONTENT
Fig 4.3.15.1 M odified proctor compaction tes t
Dept. of C ivil Engineering, JCE, Belgaum
Page 34
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.4 CALIFORN IA BEARING RATIO TES T This is a penetration test developed by the California division of highways, as a method for evaluating the stability of soil sub grade and other flexible pavement materials test results have been co related with flexible pavement thickness requirements for highways and air fields. The CBR test may be conducted in the laboratory on a prepared specimen in a mould or in-situ in the field. California bearing ratio is the ratio of force per unit area required to penetrate in to a soil mass with a circular plunger of 50mm diameter at the rate of1.25mm /min. Based
on
the
modified
proctor
test
results for different combinations of Red soil ad Black cotton soil, the best combination which yielded the best results i.e. max MDD and OMC where considered for the CBR test. Further to this obtained combination we used
Geo
grids
of
cell
size
1cm×1cm
as
reinforce material to strengthen the weak soil and improve CBR value of the soil and hence reduce the thickness of pavement.
Fig – 4.4.1 CBR Test The bes t combination is listed below:
MIX - 3 Red Soil with 5% GGBS, 10% Fly ash and 10% Quarry dust.
MIX – 1 Black Soil with 5% GGBS, 10% Fly ash and 10% Quarry dust.
Dept. of C ivil Engineering, JCE, Belgaum
Page 35
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
4.4.1 TEST P ROCEDURE Take representative sample of soil weighing approximately 6kg and mix thoroughly at OMC.
Record the empty weight of the mould with base plate, with extension collar removed (m1).
Replace the extension collar of the mould.
Insert a spacer disc over the base plate and place a coarse filter paper on the top of the
spacer disc. Place the mould on a solid base such as a concrete floor or plinth and compact the wet soil in to the mould in five layers of approximately equal mass each layer being given 56 blows with 4.90kg hammer equally distributed and dropped from a height of 450 mm above the soil.
Between 1st and 2nd layer of best mix combination of soil Geo-grid is placed .Geogrid is not used for only red so il and black soil but only used for mix.
The amount of soil used shall be sufficient to fill the mould, leaving not more than about 6mm to be struck off when the extension collar is removed.
Remove the extension collar and carefully level the compacted soil to the top of the mould by means of a straight edge.
Remove the spacer disc by inverting the mould and weigh the mould with compacted soil (m2).
Place a filter paper between the base plate and the inverted mould.
Replace the extension collar of the mould.
Dept. of C ivil Engineering, JCE, Belgaum
Page 36
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique Load
Plunger of 50mm diameter
Surcharge Soil layer above Geo grid Geo - grid
Soil layer compacted in 4 lifts
4.4 .2 FORMULATION
CBR value is calculated using the relation:
CBR, % =
…….4.4.2
Dept. of C ivil Engineering, JCE, Belgaum
Page 37
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique CBR value for Re d soil SL.no
Penetration
Proving ring Load applied
(mm)
reading
(kg)
1
0
0
0
2
0.5
65
06.89
3
1
142
15.05
4
1.5
214
22.68
5
2
285
30.21
6
2.5
360
38.16
7
3
432
45.79
8
4
567
60.1
9
5
697
73.88
10
7.5
857
90.84
11
10
1056
111.93
12
12.5
1202
127.41
15
1330
140.90
13
Table – 4.4.2.1 CBR value of Red soil
CBR RED SOIL
160 140 120 100
N K 80 in 60 d a o 40 L 20 0
0
5
10
15
20
Penetration in mm Fig -4.4.2.1 load – penetration curve for red soil Dept. of C ivil Engineering, JCE, Belgaum
Page 38
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
Calculations : 2
Area of plunger of dia 5 cm = 19.6 cm
Pressure at 2.5 mm penetration =
Pressure at 5.0 mm penetration =
CBR, % =
2
kg/cm
2
kg/cm
At 2.5 mm penetration
=
= 2.78% 3.0%
At 5.0 mm penetration
=
= 3.58% 4.0% Considering CBR value
= 3.0%
Dept. of C ivil Engineering, JCE, Belgaum
Page 39
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique CBR value for Red s oil with 5%GGBS,14%Fly ash,14%Quarry dus t & Ge ogrid SL.no
Penetration (mm)
Proving ring Load applied reading
(kg)
1
0
0
0
2
0.5
68
12.58
3
1
138
25.53
4
1.5
210
38.85
5
2
280
51.8
6
2.5
351
64.94
7
3
420
77.7
8
4
558
103.23
9
5
696
128.76
10
7.5
1054
194.99
11
10
1395
258.07
12
12.5
1785
330.22
15
2348
434.38
13
Table – 4.4.2.2 CBR value of Red soil
CBR RED MIX COMBINATION
500 450
400 350
N K in d a o L
300 250 200 150
100 50 0
0
5
10
15
Penetration in mm Fig -4.4.2.2 load – penetration curve for red soil Dept. of C ivil Engineering, JCE, Belgaum
Page 40
20
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
Calculations: 2
Area of plunger of dia 5 cm = 19.6 cm
Pressure at 2.5 mm penetration =
Pressure at 5.0 mm penetration =
CBR, % =
2
kg/cm
2
kg/cm
At 2.5 mm penetration
=
= 4.73% 5.0%
At 5.0 mm penetration
=
= 6.25% Considering CBR value
= 5.0%
Dept. of C ivil Engineering, JCE, Belgaum
Page 41
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique CBR value for Black cotton soil SL.no
Penetration
Proving ring Load applied
(mm)
reading
(kg)
1
0
0
0
2
0.5
95
7.6
3
1
170
13.6
4
1.5
250
20
5
2
330
26.4
6
2.5
405
32.4
7
3
468
37.44
8
4
579
46.32
9
5
662
52.96
10
7.5
784
62.72
11
10
829
66.32
12
12.5
860
68.8
Table – 4.4.2.3 CBR value of Red soil
CBR BLACK COTTON SOIL
80 70 60
N 50 K 40 in d 30 a o L 20 10 0 0
5
10
15
Penetration in mm Fig -4.4.2.3 load – penetration curve for red soil
Dept. of C ivil Engineering, JCE, Belgaum
Page 42
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
Calculations : 2
Area of plunger of dia 5 cm = 19.6 cm
Pressure at 2.5 mm penetration =
Pressure at 5.0 mm penetration =
CBR, % =
2
kg/cm
2
kg/cm
At 2.5 mm penetration
=
= 3.13% 3.0%
At 5.0 mm penetration
=
= 3.4% 4.0% Considering CBR value = 3.0%
Dept. of C ivil Engineering, JCE, Belgaum
Page 43
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique CBR value for Black cotton soil with 5%GGBS,10%Fly ash,10%Quarry dus t&Geogrid SL.no
Penetration (mm)
Proving ring Load applied reading
(kg)
1
0
0
0
2
0.5
70
12.95
3
1
140
25.9
4
1.5
208
38.48
5
2
271
50.14
6
2.5
330
61.05
7
3
382
70.67
8
4
485
89.72
9
5
570
105.45
10
7.5
755
139.67
11
10
885
163.73
12
12.5
965
178.53
15
1020
188.7
13
Table – 4.4.2.4 CBR value of Red soil
CBR BLACK COTTON SOIL MIX
200
180 160 140
N 120 K 100 in 80 d a 60 o L 40 20 0 0
5
10
Penetration in mm
15
Fig -4.4.2.4 load – penetration curve for red soil
Dept. of C ivil Engineering, JCE, Belgaum
Page 44
20
Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
Calculations : 2
Area of plunger of dia 5 cm = 19.6 cm
Pressure at 2.5 mm penetration =
Pressure at 5.0 mm penetration =
CBR, % =
2
kg/cm
2
kg/cm
At 2.5 mm penetration
=
= 4.45% 5.0%
At 5.0 mm penetration
=
= 5.12% Considering CBR value
= 5.0%
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
CHAPTER – 5 DESIGN OF F LEXIBLE P AVEMENT 5.1 GENERAL The design of flexible pavement involves the interplay of sveral variables such as, the wheel loads, traffic, climate, terrain, and sub- grade conditions. With a view to have a unified approach for working out the design of flexible pavement, IRC guidelines are being followed. These are based on CBR values. For the purpose of the guidelines, flexible pavements are considered to include the pavements which have the bituminous surfacing and granular base and sub – base courses conforming to IRC standards. Based on the performance of existing designs using analytical approach, simple design charts and a catalogue of pavement designs have been added for use of field Engineers. The pavement designs for sub grade CBR values ranging from 2% - 10% and design traffic ranging from 1msa – 150msa for an average annual pavement temperature of 35 C. For estimating the design traffic the following information is needed, i.
Initial traffic after construction in terms of number of commercial vehicles per day (CVPD).
ii.
Traffic growth rate during the design life of percentage.
iii.
Design life in number of years.
iv.
Vehicle damage factor (VDF)
v.
Distribution of commercial traffic over the carriage way.
Based on these, the design thickness is obtained from the charts in IRC 37-2001.
5. 2 CALCULATION For the design consideration the following data where being obtained from the Transport Department of Goa and Karnataka State. The values are listed below,
i. ii.
Number of commercial vehicle as per last count (P) = 2000 Annual growth rate ofcommercial vehicles (r) = 8.5%
iii.
Number of years between last count and year of completion of construction (x) = 3 years
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique iv.
Design life in years (n) = 10 years
v.
Vehicle damage factor (F) = 4.5 for more than 1500 vehicles.
vi.
Lane distribution factor (D) =75% for 2 lane single carriage way.
For Red Soil only:
As per IRC Method 37 – 2001 the design procedure is as follows: A = P (1 + r) x
………..5.2.1 3
= 2000 (1 + 0.085) = 2554.57 2555. Design traffic in terms of cumulative number of standard axles,
N = 365 = 365
()
()
………..5.2.2
= 46.68msa. Corresponding to this design traff ic, pavement thickness can be calculated from IRC chart for Pavement Design Catalogue. Referring to the Fig 3.8 (b) in IRC 37 - 2001 corresponding to CBR – 3% pavement thickness required is 810 for 30msa and 830 for 50msa. Interpolating these values, the pavement thickness for 46.68msa,
t = 810 +
() ()
( )
………..5.2.3
= 826.68 830mm. The pavement compositi on may be Sub Base = 380mm Base = 250mm Dense Bituminous macadam (DBM) = 160mm Bituminous concrete = 40mm . The total pavement thickness a per IRC design guidelines is 830mm Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique For Red Soil Mix:
As per IRC Method 37 – 2001 the design procedure is as follows: A = P (1 + r) x = 2000 (1 + 0.085)3 = 2554.57 2555.
Design traffic in terms of cumulative number of standard axles,
N = 365 = 365
()
()
= 46.68msa. Corresponding to this design traff ic, pavement thickness can be calculated from IRC chart for Pavement Design Catalogue. Referring to the Fig 3.8 (d) in IRC 37 - 2001 corresponding to CBR – 5% pavement thickness required is 710 for 30msa and 730for 50msa. Interpolating these values, the pavement thickness for 46.68msa,
t = 710 +
() ()
( )
= 726.68 730mm.
The pavement composition may be Sub Base = 300mm Base = 250mm Dense Bituminous macadam (DBM) = 140mm Bituminous concrete = 40mm . The total pavement thickness a per IRC design guidelines is 730mm The re is 100mm re duction in the paveme nt thickness for Red soil M ix as compared to only Red s oil without any admixture.
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique For Black Cotton Soil only:
As per IRC Method 37 – 2001 the design procedure is as follows: A = P (1 + r) x = 2000 (1 + 0.085)3 = 2554.57 2555.
Design traffic in terms of cumulative number of standard axles,
N = 365 = 365
()
()
= 46.68msa. Corresponding to this design traff ic, pavement thickness can be calculated from IRC chart for Pavement Design Catalogue. Referring to the Fig 3.8 (a) in IRC 37 - 2001 corresponding toCBR – 2% pavement thickness required is 900 for 30msa and 925for 50msa. Interpolating these values, the pavement thickness for 46.68msa,
t = 900 +
() ()
( )
= 920.85 925mm. The pavement composition may be Sub Base = 460mm Base = 250mm Dense Bituminous macadam (DBM) = 175mm Bituminous concrete = 40mm . The total pavement thickness a per IRC design guidelines is 925mm
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique For Black Soil Mix:
As per IRC Method 37 – 2001 the design procedure is as follows: A = P (1 + r) x = 2000 (1 + 0.085)3 = 2554.57 2555.
Design traffic in terms of cumulative number of standard axles,
N = 365 = 365
()
()
= 46.68msa. Corresponding to this design traff ic, pavement thickness can be calculated from IRC chart for Pavement Design Catalogue. Referring to the Fig 3.8 (d) in IRC 37 - 2001 corresponding to CBR – 5% pavement thickness required is 710 for 30msa and 730 for 50msa. Interpolating these values, the pavement thickness for 46.68msa,
t = 710 +
() ()
( )
= 726.68 730mm.
The pavement composition may be Sub Base = 300mm Base = 250mm Dense Bituminous macadam (DBM) = 140mm Bituminous concrete = 40mm . The total pavement thickness a per IRC design guidelines is 730mm The re is 195mm reduction in the paveme nt thickne s s for Black cotton soil M ix as compare d to only Black cotton soil without any admixture.
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
CHAPTER – 6 SUMMARY AND CONCLUSIONS 6.1 SUMMARY In the present study, an attempt has been made to find out the effect of Fly ash, GGBS, Quarry dust andGeo grids use in the stabilization of soil and constructio n of flexible pavement. Here in the study six types of Red soil mixes and six Black cotton soil mixes were carried out. The details of the mixes are as below; 1) Red Soil:
i.
Mix – 1 Red Soil with 5% GGBS, 10% Fly ash, 10% Quarry dust.
ii.
Mix – 2 Red Soil with 5% GGBS, 12% Fly ash, 12% Quarry dust.
iii.
Mix – 3 Red Soil with 5% GGBS, 14% Fly ash, 14% Quarry dust.
iv.
Mix – 4 Red Soil with 5% GGBS, 16% Fly ash, 16% Quarry dust.
v.
Mix – 5 Red Soil with 5% GGBS, 18% Fly ash, 18% Quarry dust.
vi.
Mix – 6 Red Soil with 5% GGBS, 20% Fly ash, 20% Quarry dust.
2) Black Cotton Soil:
i.
Mix – 1 Black Cotton Soil with 5% GGBS, 10% Fly ash, 10% Quarry dust.
ii.
Mix – 2 Black Cotton Soil with 5% GGBS, 12% Fly ash, 12% Quarry dust.
iii.
Mix – 3 Black Cotton Soil with 5% GGBS, 14% Fly ash, 14% Quarry dust.
iv.
Mix – 4 Black Cotton Soil with 5% GGBS, 16% Fly ash, 16% Quarry dust.
v.
Mix – 5 Black Cotton Soil with 5% GGBS, 18% Fly ash, 18% Quarry dust.
vi.
Mix – 6 Black Cotton Soil with 5% GGBS, 20% Fly ash, 20% Quarry dust. In this study, For Red Soil Mix-3 showed comparatively better performance, where
as other Mixes are comparatively have lesser MDD and Specific gravity. It can be inferred that higher the MDD results in higher strength of soil sub grade to withstand the heavy wheel loads coming on the pavement, durability, also the expansive nature of soil is reduced in the particular Mix - 3. The study has been limited use of GGBS 5% only.
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique In this study, For Black Cotton Soil Mix - 1 showed comparatively better performance, where as other Mixes are comparatively have lesser MDD and Specific gravity. There is drastic change in the properties of Black Cotton Soil and we obtained the similar properties of as that of Red soil Mix – 3. It can be inferred that higher the MDD results in higher strength of soil sub grade to withstand the heavy wheel loads coming on the pavement, durability, also the expansive nature of soil is reduced in the particular Mix - 1. The study has been ilmited use of GGBS 5%only.
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
6.2 CONCLUSIONS Based on the experimental investigations some of the major conclusions of this work are drawn: 1) The investigation have shown that using GGBS along with Fly ash and Quarry dust as base materials, it is possible to stabilize the weak sub grade soil . 2) By using Geo grid as reinforcing material to the soil the load sustaining property of soil and strength is increased because of good interlocking of Soil granules. 3) There is 100mm reduction in the pavement thickness for Red soil Mix as compared to only Red soil without any admixture. 4) There is 195mm reduction in the pavement thickness for Black cotton soil Mix as compared to only B lack cotton soil with out any admixture. 5) As thickness of pavementreduces the cost of pavement construction and maintenance also reduced hence increasing the durabilityof pavement, sustaining higher wheel loads. 6) By using these stabilizing materials we can strengthen the weak soil not only in pavement construction but also in Building Construction, the Safe bearing Capacity(SBC) can be enhanced or improved.
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
6.3 S COPE OF THE FUTURE STUDY 1. Study on the properties of soil using combination of Fly ash and Blast furnace slag and Quarry dust on short term properties such as water absorption, Shear stresses are very much required to get the required confidence on the material. 2. The percentage of GGBS was restricted to 5% only. Hence we can study the properties for different percentages of GGBS. 3. It will also be interesting to investigate the behaviour of Soil at different molar ratio of NaOH. 4. In this study, the design of flexible pavement is carried out further the study can be extended to the design ofRigid pavements. 5. In this study, only Geo grids are used as reinforcing materials further the study can be extended to the Geo cells, Geo nets, Geo textiles etc.
Dept. of C ivil Engineering, JCE, Belgaum
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Performance evaluatio n of weak sub grade soil and treating the subseque nt layers of the pavement by using advanced stabilization technique
6.4 BIBLOGRAPHY Textbook of “Soil Mechanics and Foundations”by Dr. B.C. Punmia, Ashok Kumar Jain, Arun Kumar Jain.
Textbook of “Highway Engineering”by Dr. S.K. Khanna and Dr. C.E.G. Justo. Research Paper on “Performance evaluation of Geo synthetic Reinforced Un -Paved Roads” by Prof. Gali Madhavi Latha, IndianInstitute of Science, Bangalore.
Research
Paper
on “Stabilization
of
Expansive
soils
using
Fly
ash” by
S.Bhuvaneshwari, R.G. Robinson, S.R. Gandhi.
Research Report on “ Final Report on Durability and Strength development of Ground Granulated Blast Fur nace Slag” by Peter W.C. Leung and H.D. Wong.
Research Paper on “ Improving the Geo- Technical Properties of Soil by using FlyAsh and Quarry dust ” by Akshaya Kumar Sabat, Bidula Bose.
IRC Code 37 – 2001 “Guidelines for the design of flexible pavements” .
Dept. of C ivil Engineering, JCE, Belgaum
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