 Next part of embankment material, we will discuss about this highway construction materials, equipment and practice. So, basically if I start with this function and significance of subgrade properties, that means it will come under basement of soil of road bed and important for structural and pavement life should not deflect excessively due to dynamic loading may be in field or in embankment compacted or natural subgrade. Now if you come back to embankment section cotton field of embankment section, now if you look at this figure this is your existing ground, this is how this is your this entire part top part is your existing ground, if with this existing ground if you cut it then I can classify into three parts, one is your subgrade level, this is your subgrade level, then middle is your sub base, then top is your base course, top is your base course. So, this is a typical cut section, now in a pavement if you look at this now typical field section, this is a typical cut section that means we are discussing cotton field of embankment sections for highways. Now typical field section, in typical field section what will happen will feel it will make this embankment and typical cut section already ground level is at the top, we are cut it and make the road or highway purpose for particularly field section will make your ground surface is here somewhere else here or may be below, will feel and make it suitable for highway. Now this is your this is your subgrade first one is your existing ground surface somewhere else either here or may be here this is your existing ground surface it is written here, then is your subgrade layer and this entire part is your subgrade layer, then this is your formation level and top one is your pavement. So, these are the two sections, two sections one is your field section other is your cut section. Now subgrade soil if you come back to here, if you look at here this is your subgrade layer that means this is your subgrade soil and this is also a subgrade layer that means subgrade soil both cut and field subgrade soil may be consist of granular or coarse grained fine grained or organic. Now what are the soil what are the condition unsuitable soil material for subgrade what are the soil material to be unsuitable that means this soil should not be considered number one clay soil which contains the value of liquid limit more than 80 percent which contains the value of liquid limit more than 80 percent and or or plastic index plasticity index more than 55 percent. If a clay soil whose liquid limit is more than 80 percent and or or plasticity index more than 55 percent in that case it is unsuitable soil material for subgrade if it is inflammable material that means inflammable means if some soil is mixed with oil kind of material or organic or organic clay soil then it is not suitable for subgrade soil material contains lots of rotten roots what happens sometimes in the soil inside this tree root will go and it has been over the period of time it become rotten. So what will happen if there are lot of rotten roots grass and other vegetations then also it is not suitable soil which is soft unstable because it is too wet or dry which makes it difficult to compact properly that means which is too soft and too soft then it is not going to consider for subgrade material properties associated with subgrade soil we are now discussing about the subgrade soil properties associated with the subgrade soil volume change with water load sustaining power compression under static load workability during weight periods easy of drainage and compatibility now desirable properties of soil as subgrade material it based on stability incompressibility minimum changes in volume and stability under adverse condition of weather and ground water then permeance of strength good drainage then easy or ease of compaction classification and identification of soil as subgrade material how to identify this means there are many soil materials are there how to identify which soil material to be consider as a subgrade material it is based on the index properties that means size distribution liquid limit plasticity index shrinkage limit field moisture equivalent that means adsorbed water compacted dry density centrifuge moisture equivalent indians standard grain size classification generally in indians standard we have discussed also earlier gravel sand silt and clay as per the indians standard we have 4 soil classification 1 is your gravel then your sand sand lies between 2 mm to 0.06 mm within the sand then it has been classified into 3 parts coarse medium and fine then silt lies between 0.06 mm to 0.002 mm so again silt has been classified as coarse medium and fine then clay lies between 0.002 mm 0.006 mm to 0.002 mm so it lies between coarse medium and fine so grain size distribution so significance of your GSD grain size distribution to know the relative proportion of different grain sizes what is the significance to know the relative proportion of different sizes and important factor influencing the geotechnical characteristics of a coarse grain soil first one is your grain size distribution if you look at here significance of grain size distribution means to know the relative proportion of different grain size and important factor influencing the geotechnical characteristics of coarse grain soil not important in fine grain soils now we will start the first one is your to know the relative proportion of different grain sizes in coarse grain soils by sieve analysis this is how we are doing the sieve analysis by means of stock of sieves and sieves we are doing the sieve analysis in fine grain soil by means of hydrometer analysis using this hydrometer that means soil and water suspension in a measuring jar then putting hydrometer inside you can find it out fine grain soil as well as coarse grain soil by means of sieve analysis so based on a s h o s h o classification based on public road p r 19 28 a 1 to a 7 classification based on group index g i a function of material passing through 200 mesh sieve that means 0.74 mm group index may be calculated as 0.2 a plus 0.005 ac plus 0.01 b d so minimum group index is equal to 0 maximum group index is equal to 20 when passing 200 mesh sieve liquid limit and plasticity index is equal to 0 maximum group index are 75 60 and 30 respectively higher g i that means higher the group index that means poorer soil as sub grade material if the group index is very high that means it indicates poorer soil that means it is a poorer soil as sub grade material if you look at the group index values as per given in tabular form if group index is 0 that means soil condition is excellent if group index is 1 that is good between 2 to 4 it is fair 5 to 9 it is poor 10 to 20 is very poor that means if the group index value is very high that means it is not suitable for highway material or sub grade material so indian standard soil classification that means based on modification on unified soil classification system gravel generally we take it 80 to 4.75 mm sand 4.75 mm to 0.075 mm silt 75 micron to 2 micron clay generally less than 2 micron so particle size distribution sieving and sedimentation analysis as per indian standard 2720 part 4 1985 and these are the 2 cores and liquid limit and plastic limit as per indian standard 2720 part 5 1985 dry density specification for road and bridge third revision 1995 m or th morth specification specification recommends 97% dry density that means heavy compaction by modified proctor density as per indian standard 2720 part 8 it has been 97% dry density it has been used national highway state highway mdr and heavily traffic road at least 97% by standard proctor density one is your by heavy compaction modified proctor density one is modified proctor density other is your by means of standard proctor density at least 97% it has been given by indian standard 2720 part 7 then sub grade soil strength that means assessed in terms of severe of sub grade soil for most critical moisture conditions strength has to be measured by means of severe california bearing ratio test the strength has to be measured that means soil type moisture content dry density internal structure of the soil type and mode of stress application what are the different test for sub grade soil or embankment for sub grade soil or embankment you have to do grain size analysis proctor compaction both light and heavy heavy means modified proctor light means proctor compaction california bearing ratio that means severe and differential free swell that called dfs liquid limit plastic limit for sub base or administer grain size analysis proctor compaction both light and heavy california bearing ratio differential free swell and liquid limit and plastic limit you see for sub base or administer or may be sub grade soil embankment what are the test required in the laboratory sub grade performance load bearing capacity in the load bearing capacity is affected by degree of compaction moisture content and soil type california bearing ratio test and falling weight deflectometer back calculation and other methods has been used have been used moisture content affects the sub grade properties like load bearing capacity it affect the sub grade properties like load bearing capacity shrinkage and swelling influence by drainage ground water table elevation infiltration or pavement porosity shrinkage and or swelling soils with excessive fines generally soils with excessive fines content suppose soil has more than 50 percent or 60 percent fine content then this may be susceptible to heave in northern climate moisture content water table precipitation soil permeability drainage conditions extend to which pavements is water proof stability of soil if you look at the stability of soil it depends upon stress deformation characteristic of soil stability of soil it depends on the stress deformation characteristics of soil that means visco elastic deformation visco elastic deformation repeated application of stress repeated that means repeated load generally applied by means of traffic loading repeated load means suppose there are n number of vehicles passes in the road that means what will happen again and again they will apply this load same same position so repeated application of stress generally by means of frequency of loading cycle magnitude of stress number of repetitions number of repetitions then static stress period of period of stress application intensity of stress period of stress application and intensity of stress then next part is your evaluation of strength of sub grade soil how do you find it out strength of this sub grade soil first one is by means of shear test or you can shear test in that shear test what are the different shear test you can do by direct shear test or triaxial compression test or on confined compression test then bearing test also you have to conduct then also you will have to go for your penetration test then next most important part that is your california bearing ratio test a penetration test where in a standard piston having an area of 3 inch that means it is 50 mm diameter that means it is 50 mm diameter is used to penetrate the soil at a standard rate of 1.25 mm per minute at a standard rate of 1.25 mm per minute that means every minute it will penetrate 1.25 mm the pressure up to a penetration of 12.5 mm and its ratio to the bearing value of a standard crossed or rock is determined as severe look at the definition the pressure up to a penetration of 12.5 mm means up to 12.5 mm how much pressure coming to the soil and its ratio to the bearing value of standard crossed rock is termed as severe that means california bearing ratio severe testing machines if you look at the severe testing machine there is a standard plunger this is your standard plunger then with this annular weight sometimes optional then your sample this is your soil sample then this is your standard mold in a standard mold in a standard mold soil sample has been taken then with that a standard plunger is there from where this your applied load will be load has been applied then transducer here is your transducer it will be connected to your applied load to measure the penetration this is your pictorial view pictorial view of your severe testing machines complete severe testing machine california bearing ratio test now strength measure for unbound material piston advance at 1.3 mm per minute rate measured load at 2.5 mm penetration means whatever load it is coming it measure every 2.5 mm penetration so severe is equal to severe is equal to 100 into p 2.5 means how much pressure is coming about 2.5 mm by p standard p standard p p s 3d standard load adopted for different penetrations for the standard material with a severe value of 100 percent penetration of plunger then only standard load if you are using 1 3 7 0 k g it is 2.5 mm if it is 2 0 5 k g it is 5.0 mm if it is 2 6 3 0 k g then it is 7.5 mm if it is 3 1 8 0 k g 10 mm and 3 6 0 0 it is 12.5 mm then next part is your aggregate physical properties that means aggregate can be classified by their mineral chemical and physical properties you will have to classify the aggregate based on their mineral chemical and physical properties and aggregate physical properties are a direct result of mineral and chemical properties maximum size the smallest sieve through which 100 percent of aggregate sample particle passes this is called your maximum size that means the smallest sieve through which 100 percent of aggregate sample particle passes this is called maximum size then your nominal maximum size the largest sieve that retains some of the aggregate particles but generally not more than 10 percent by weight nominal maximum size means the largest sieve which retains some of the aggregate not more than 10 percent of total weight suppose say total weight you are taking 200 gram about this 10 percent of the 200 gram not more than that means the retaining it should retain less than 10 percent of 200 gram so this is called nominal maximum size so what are the test on aggregate generally we go for so test on aggregate we generally go for aggregate impact test then flakiness and elongation test if you look at this is your aggregate flakiness and elongation test then is your angularity index test then loss anglis abrasion test then water absorption test specific gravity test and soundness test these are all test to find it out if you come back to here first part is your if you look at here in a pavement as a cut and field section we have earlier discussed the sub grade layer that means sub grade soil what kind of what kind of soil you have to consider if you consider based on what and what are what are the test required then your if you look at the aggregate generally this aggregate base course base course this aggregate will come here formation level or may be base course level this aggregate what kind of test you are supposed to do and what is the best aggregate then accordingly you have to decide these are all test on aggregate will have to carry out to decide whether this aggregate is fit for this sub grade material that means road material or not if you look at here in a beaker in a basin in a basin aggregate gradation in a basin if you look at here first one is your in a basin this is your soil one lb of soil then if you look at here one lb of gravel then light weight aggregate how the aggregate gradation has been done then this is your limestone then this is your sand that means if I take a same beaker or same jar in the same jar the volume is fixed the volume is fixed in the same volume if I am taking a certain amount of one pound of suppose a one kg of soil if I put it how the gradation comes into picture it feels half it feels half now light weight aggregate it feels full now the limestone is slightly higher now the sand is less than your soil this is how this aggregate gradation generally we do now if you look at here types of gradations if you look at here types of gradations now different types of aggregate if you look at here I am I am putting this one two and three aggregates now uniformly graded if I say this aggregate is uniformly graded what does it mean it means uniformly graded means few point of contact few point of contact then poor interlock poor interlock that means particle to particle interlock will be very poor then high permeability if I say uniformly graded that means this seepage characteristics it will allow it is allow water to flow seepage characteristics will be more then the moment I say aggregate well graded that means there is a good interlock good interlock means particle to particle particle to particle inside this the forces particle to particle forces interlocking forces will be very strong that is why this is called good interlock low permeability if I compare those this two uniformly graded and well graded that means its drainage capacity will be low as compared to uniformly graded then gap graded if I say this is a gap graded only limited size if I say gap graded means only limited size are there not all size suppose I say it will start with this sand gravel shield for a soil or clay if I say in this if it is a gap graded that means only some part of shield and sand is there some part is missing some part of the grading some part some proportion of the aggregate are missing then good interlock in this case the interlocking forces interlocking forces between this aggregate it will be a good aggregate good interlock then next is your as compared to this two that means uniformly graded and well graded this will be a low permeability this will be a low permeability next is your aggregate characterization now how do you characterize your aggregate physical properties first one first one is your aggregate physical properties in aggregate physical properties maximum aggregate size means there are different sizes of aggregate you will have to find it out maximum aggregate size then what is your gradation right now we have discussed this gradation about uniformly graded well graded and gap graded then you have to make it what is the gradation then other aggregate properties that means what are the other aggregate properties toughness resistance specific gravity of the aggregate particle shape and surface texture particle shape means how it looks what is the shape it is circular particle shape it is circular or it is angular or may be it is sub angular or may be any any kind of shape what is the shape then surface texture how your surface texture is there texture means how surface looks surface looks is very like shiny or may be it is dented that that has to be classification like you have to do it then durability and soundness then your cleanness how clean it is means whether it is a clean or not how cleanness it is if you look at here crude oil processing this has to be means by how this crude oil processing has been done for this sub grade mass because once you put once you put your sub grade then your aggregate then you have to allow your between and other part so if I divide into if I take it into cut section or may be field section first layer is your ground surface this is your existing ground surface then is your sub grade layer sub grade layer means it is a soil what kind of sub grade you are going to to take it then your formation or aggregate what we are we have discussed now this is your aggregate above this aggregate level you have to make a coating by means of crude oil it may be in the form of between tar paving grade or industrial grades if you look at the four parts bitumen is your distillation of petroleum crude it is a distillation of petroleum crude then tar is your destructive distillation of coal or wood that means bitumen what you are getting this from your petroleum then tar we are getting from coal or wood then paving grade this has been generally used particularly air fields or roads then industrial grades means it is a water proving of structures or industrial floors if you look at here generally we use this bitumen or tar generally for road purpose for paving grades generally for aerodrome air fields for industrial we are providing water proving of structures or industrial floors this all it comes from your crude oil processing this is this is just a how the crude oil has come from this petroleum gas gasoline kerosene diesel oil lubricants wax fuel oil and bitumen these are all given in detail from where if you look at here gas where it has been used then your gasoline and kerosene then diesel oils then lubricants where it has been used then fuel oil and bitumen if you look at here bitumen where it has been used this detail in a diagrammatically view if you see this view then you can have an idea so what are the construction practice construction of a embankment of for sub grade material generally materials used for construction of embankment for sub grades materials soil muram and gravel these are the materials has been used soil muram you have seen red color muram and gravel unsuitable materials materials from swamps or marshes clay with as I said earlier liquid limit greater than 70 plasticity index greater than 45 free swelling index more than 50 that means it is a highly expensive soil size of course material these are all your for these are the requirement for your material to be whether it is suitable or not to be suitable embankments less than equal to 75 mm sub grade particularly thickness is your less than equal to 75 a 50 mm density of material of embankment and sub grade if you look at here type of work embankment up to 3 meter height not subjected to extensive flooding then maximum dry density with heavy compaction as for what is the is indian standard 270 part 8 recommend not less than 15.2 kilo Newton per cubic meter similarly embankment exceeding 3 meter height or embankment of any height subjected to long periods of inundation that means flooding not less than 16.0 kilo Newton per cubic meter sub grade and are then soldiers and barges and backfill not less than 17.5 kilo Newton per cubic meter sub grade and are then soldiers not less than 97 if you see embankment not less than 95 expansive clay of acceptable sub grade and 500 mm portion just below the sub grade not allowed similarly remaining portion of embankment not less than 90 mm these are all your if you look at these two these two tables one table is your density materials of embankment and sub grade what is the type of work what should be a maximum density this is about the table then construction operations setting out this alignment dewatering compacting ground to support embankment and sub grade then spreading of material and moisture content sub base base and soldiers material natural sand if you look at if you are using for sub base or base sub base one is your first part we have discussed this is about your sub grade now if you come back to here first one again sub grade sub grade this is your sub grade then sub base then base we have discussed about sub grade then your sub base or base material for particularly sub base and base natural sand muram gravel cross stone or combination of all lime treated if high percentage of clay is found then construction operation preparation of sub grade then spreading sub base material and moisture content generally maintain one percent to two percent then construction of water bound macadam road WBM is your water bound macadam road constructed of 12 inches of stone overall overall you have to put it 12 inches of stone then these are all the procedures how will follow this construction of water bound macadam road course aggregate water bound macadam road then in that case hard and soft aggregate then screening then binding of the materials then what are the different properties different properties durability durability hard free if I take it by means of loss angle abrasion value for sub base maximum it should be 60 base course it should be 50 and surface course it should be 40 AI value 50 40 and 30 plankiness index first one sub base it should not be there then it should be 15 and 15 for base course as well as surfacing course soft aggregates in WBM over bound brick material generally used or naturally occurring soft aggregate or conquer or laterate cross slag form from this blast furnace also sometimes it has been used size and grading requirement of course aggregate for WBM this is detail given different size range if you are taking 90 to 40 and what is by percentage of weights it should pass these are all tables it is given then how do you screen it for filling the voids in compacted layer IRC suggest IRC suggest use of non plastic material that means conquer muram or gravel should satisfy this is the condition should satisfy liquid limit 20 percent plasticity index 6 percent percent of fineness passing 75 micron sieve it should be 10 percent so binding material generally we use the binding material to prevent raveling and rubbing between the aggregate grain material so plasticity index 4 to 9 percent for surfing surface course plasticity index is equal to 6 percent with sub base and base course no binding material for muram and gravel of low plasticity index this is all about embankment material requirement for highway constructions how what is your sub base what is your base what is your base material or sub base material or sub grade material what are the requirement this is all about for particularly construction of embankment or highway material thank you