Thank you Sir......these lab experiment are very useful for me to understand during covid -19 because in this situation our colleges are going completely online so these videos are very helpful for students.......... again thank you so much sir.....
Very professional and well explained. Very compliant to the regulation. Yet, let me give you a precise tip: the first done, with the mold and the hammer, actually is not the CBR, but the Proctor test. The CBR is the last, done with the assistant. The two tests are strictly related (CBR is gonna be executed after the proctor) but they are two different test. The proctor test is aimed to evaluate the optimum, i.e. the maximum amount of water (weight %) to have the max density. Indeed, until a certain value (depending on the kinda soil), water furthers the bonds between the grains and, hence, the density, becouse of the water film between. But over a certain value, water is too much and it tends to counteract the density, making the grains submerged into water. Like all the other lab geotech. tests, this one also requires several tests; for each test the soil must be weighed, subtracting the weight of the mold (previously weighed void) and the weight of water (knowing its amount in each test) to find the net dry weight. All the results are plotted in the optimum bell curve, built step by step (water content % vs dry density in the diagram) and compared them each other, to see which one is at the top of the curve (the content of water, called optimum indeed, that gives the most performing soil).
Proctor test is usually done in a smaller mould. Without any spacer disc. Though anything is fine. And for CBR we have to prepare the sample and therefore the first is definitely part of the CBR TEST
hi sir thank you for uploading video for learning. can u explain me where we can use 3 layer comaction and where for 5 layer compaction methods and how would we analyse its loose dense soil and high dense soils
Most of the people doesn't know why 2.5 mm value is considered it is actually 1 inch according to American standard test procedure and the rock used was of 1 pound weight and it was found generally in california....
Video at 4:27 says heavy compaction of 75 blows for each layer in 5 layers. But the table shows only 56 blows. Only legend will understand. I did mot get convinced😢
Beautifully explained the CBR test. Great job Ajay sir! Also, i would like to tell NCTEL to make a correction in the video. 4:42 - Dynamic compaction table, the no. of blows in heavy compaction should be 75 (it is written 56).
First of all thank you for such clear explanation, i am here to know ans for my question, 1) how we differentiate casting of specimen at 95℅ compaction(as per MORTH), 97% compaction(as per IRS) or 100% compaction of MDD for blanket layer. 2) how setting load applied, and how much it is on dial gauge reading, Please replied it i really want to know this.
100 % compaction is not practicable at site due to less control on moisture content and other variables. So as per specified requirements compact to desired degree .
please define the no. of blows for 97 % compaction 10, 30, 65 for the cbr casting, because required no. of blows as per ASTM D1883 (10, 25, 56 blows) compaction for 95% (how to calculate 10, 30, 65 blows for 97% compaction or where are write this criteria.)
I graduated this year in my first bachelor degree in geological engineering, so if there is some one that can tell me about the scholarships let me know? Thank you.
If initial portion of your graph is curved inwards it requires correction...you can simply draw a tangent for that portion of the graph and check where the tangent meets at your X axis, that's your new 0
Soaked test give you value under worst possible conditions. Most of designers adopt this value. But if soil subgrade is unlikely to get any moisture increment after construction , unsoaked value may be taken. Refer to IRC 37 guidelines.
