@@SatishIITR I am serving in Border Roads Organization and presently posted in Bhutan as BRO is doing some strategically important Projects here .I have send request to you on LinkedIn. Regards
Thank you very much sir ! It's a really a very useful class to me and I have learnt more from you sir ! 🙏 please make such a special and more valuable and useful video ! Thanks once again for your effort to help us ! Please continue 🙏with good videos !
the lecture is very nice sir, I learnt for the first time and got understood only due to this vedio and ur simple explanation. kindly share with KENPAVE software also pls.
Good Evening Sir... Sir, As per IRC 37: 2018, The unbound base layer consists of wet mix macadam, water bound macadam, crusher run macadam, reclaimed concrete, etc., conforming to MoRTH Specifications[23]. Wet mix macadam may also consist of blast furnace slag mixed with crushed stone meeting the MoRTH Specifications. The thickness of the unbound granular layer shall not be less than 150 mm except for the crack relief layer placed over cement treated base for which the thickness shall be 100 mm. My query is that we only changed the name from WMM to Crack relief layer and thickness from 150 mm to 100 mm where CTB was used below it, but what properties have changed in WMM or Crack relief layer as no specifications have been changed while converting WMM to crack relief layer. And also the FDD has been given a minimum of 100% of MDD for Crack relief layer , so upto what extent (percentage of compaction) we can achieve at site.
Crack relief layer has the same gradation as WMM and therefore all physical tests as required for WMM should be applicable to Crack relief layer also ( I uploaded one video on Crack Relief Layer also). Further there is no concession given in the code for field density in the case of crack relief Layer also. 100 percent is needed.
Sir, at 19:11, if the embankment soil CBR is less than 5% and borrowed soil CBR is more than 5%, in this case when the Mrs is more than 100 and we limit Mrs to 100 and while recalculate the CBR which CBR equation we need to use?
Sir, If the thickness of DBM in design is given 100 mm and laid in 2-layer in the thickness of 50 m each. Then my question is according to IS -37 is that whether the 1st layer is DBM (G-1) and 2nd layer is DBM ( G-2) OR both the layer will design according to DBM ( G-2 ) based on thickness
you can do both ways, but design for lower layer and upper layer will be different. The bottom layer must be desiged as bitumen rich mix at lower air voids as suggested in the code.
Sir, At 13:29 under the Input you have mentioned Single wheel load as 40000 N. But when we consider the standard Axle load as 80000 N, the load of single wheel will be 20000 N but you have mentioned 40000 N can you please clarify?
Thank you for making huge usefull videos, if possibel please attached pfd ppt with vedios, it's help to everyone 🙏. Sir please make vedios on types of vehicle, axel configuration, max turning angle allow, types of vehicle use for urban and rural design...
Sir, in this lecture you mentioned CTB, GSB combination (6th cross section), we can use SAMI or AIL. If my design traffic is 20 MSA shall I use SAMI. If not on which criteria, I should consider for providing these crack relief layers.
Respected Sir Myself Amit Chowdhury from West bengal, My question is the CBR for soil we considered here is 4 days soaked CBR or this is field CBR of soil for both subgrade & Borrow soil ?
CBR of borrow material and CBR of subgrade soil are determined in laboratory after 4 days of soaking and then we estimate the effective CBR of Subgrade soil for design.
Sir Thanks a lot for clearing my confusion. I have one request sir if you kindly put some light on design of pavement by considering CTSB ,Granular base/ CTSB ,CTB / Long life pavement So that we can enriched Regards Amit Chowdhury
Thank You for the explanation. I could not understand why the resilient modulus of the subbase is taken as 0.2(h^0.45)* Mrsupport. Does the property(here the resilient modulus) of a material depend on its thickness(h) and the property of the supporting layer? Why should we calculate the resilient modulus instead of taking it from the test or laboratory value like the resilient moduli of materials of other layers?(From Nepal)
Yes, ideally it should be determined in the laboratory. But the method of finding Mr value of granular layer is not simple and requires sophisticated equipment, because there is no cohesion in the material. This Equation is taken from AASHTO.
In case of Cement Treated Base design, should IIITPAVE be run at two different tyre pressures? One at 0.56 MPa to check tensile strain below DBM and second at 0.8 MPa to check tensile strain below CTB?
Sir, if both the equation of Elastic modulus/Mrs are used to calculate the elastic modulus Value then which equation will be used to calculate the effective CBR value after getting the surface delfection ?!
Remember CBR is not used in the design, it is Mr value that is given as input to IITPAVE. After getting the surface deflection, find out the Mr value and this is the effective Mr of the subgrade soil. If you want to find out the effective CBR then use this Mr value to back calculate CBR. I hope it is clear now.
Sir how the poissons ratio shall be selected for the overlay design? How much it should be for the bitumineous layer in case of new over lay and old layer at the same time.
@@SatishIITR when bituminous layer (5years)-0.75 msa and Granular Layer-(15years) -2.92msa IRC 37-2018 recommend more than 2.0msa design Traffic Here Granular layer Traffic more than 2.0msa but bituminous layer below 2.0msa . Isi condition me IRC 32-2018 design karsakta hai.... Sp-72-2015 leke design karenge
Very good lecture sir thank you for that.... have some questions 1. No of oRiginal ground CBR values are coming in filed ( interval of chainage). All cbr values are different that case how to chose cbr? 2. CBT OR CBST layer practically where to use ( cold conditions or warm conditions)? 3. Is it possible to more Elaborate how to collected data, analysis and calculate actual traffic growth rate?
My answer to your queries 1. If the type of soil varies along the length of the pavement, determine CBR (three samples at least) for each type of soil and then determine 90th percentile CBR value (if Expressway, NH, SH and Urban Roads) or 80th percentile for other categories of the roads and design the pavement. 2. There is no restriction of CTB or CTSB for cold or warm condition. You need to test it for durability as per weather conditions 3. This is a different topic all together and will try to discuss in another video.
Sir, in case of CTB Layer where Prime coat can be used? 1. On CTB layer prior to SAMI 2. ON SAMI layer prior to BT Layer 3. Prime coat shall not be used ON CTB or SAMI Please provide Your valuable guidance
Sir ! Since long period I have one doubt i.e why always the thickness of subgrade is kept as 500mm both in state highways and in national highways ? Please clear my doubt sir 🙏. 🙏🙏🙏🙏🙏
@@SatishIITR Sir, Can it be concluded that if Service Road with 10 MSA traffic is a part of National Highway, then it should be designed with 90% reliability?
KGPBACK software is to calculate the modulus values of individual layers from defection data. IRC 115 is for the design of Overlay on existing pavements while IRC 37 is for deign of new pavements.
Sir can we increase bitument content to 12.5 or 13% keeping 3% target voids so that C value is increased and so the allowable tensile strain. This can be reassured during mix design by marshall test
Bitumen content 12.5 % ? Are you joking? The pavement will fail in rutting and bleeding. I hope you meant volume of bitumen and not the bitumen content.
There is not codal value for minimum volume of binder. But VFB will certainly depend on Vb and that should be within permissible limits depending upon the type of layer.
watch my video uploaded on Oct 03, 2021. It gives complete procedure including use of software to design the overlay ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yMdp9H57FWo.html
@@SatishIITR yes sir.. I got it.. thank u.. now i am confused with calculations on rutting and fatigue calculations.. when I put 11.5 and 3 to calculate M, I don’t get the same equation
