Question

Results 100% for,-270 Mg/ms 2.0 .80% Degree of 60% saturation: ? 120 Peak poor- Line of aptimum Line of optimums ero air 1.9 void 115 ? Modified Proctor 110 " Ptimuns In Com pachen Curves Standard Proctor 105 0 10 Wopt 15 Water content w (%) 20 100 25

i need these 2 questions to be answered ... plz give a clear answer

Answer 1

Compaction curve: The relationship between dry density and water content is called compaction curve

Zero air-voids line (100% degree of saturation) MDD OMC Water content

The maximum density obtained is called maximum dry density (MDD). The water content corresponding to the water content is called optimum moisture content (OMC). The optimum point is plotted corresponding to the MDD and OMC

The Zero Air Voids Line The zero air voids (ZAV) line is the combination of moisture and density that produce complete saturation of the soil or the yd obtained when there is no air in the void spaces The compaction curve theoretically does not cross this line but becomes parallel to it Remember that the values of water content, wet unit weight, and specific gravity are not constant throughout the soil. There could also be variability in the test results. Variability can result in points on the compaction curve above the ZAV line (S100%). These data points should not be thrown out Basic weight volume relationships are used to develop and equation for the ZAV line. Recall that Since S 1 if the saturation is equal to 100 percent, the relationship can be substituted into the above equation to yield the final equation for the ZAV line 1 Gsw Note that G and are constants for a given soil. Therefore the ZAV line is a linear function of water content. To draw the ZAV line, simply enter values of wand compute the corresponding value of %

Procedure 1. Obtain approximately 5 lbs. of undried soil passing the No. 4 sieve for each test being performed. A minimum of 5 tests is required, 6 is preferred 2. Add enough water to each test sample to bring the water content within range of optimum. Test samples should be prepared in approximately 2% increments First trial water content might be 4%. 3. Determine the weight (W) and volume (V) of the Proctor compaction mold or with base plate (do not measure the extension). Use the scale sensitive to 0.1 lb to determine the weight of the mold. 4. Determine the weight (Wtin) of the moisture tins. Use the scale sensitive to .01 g to determine these weights 5. Assemble and secure the mold and extension to the base plate. Make sure that the apparatus is placed on a rigid foundation (i.e., concrete slab). This is important not only for safety reasons, but to ensure that the compaction effort is applied to the soil and not the foundation. Compact the first test specimen in the mold in five equal layers. 6. a. For the first layer, fill the mold about one third with loose soil. b. Compact the lift with 25 blows of the compaction hammer. Make sure that the hammer is kept vertical and the guide sleeve is not lifted. Also take care to evenly distribute the blows over the entire mold. Score the top of the layer with a metal spatula. For the second layer, fill up to two third level of the mold Repeat steps b and c. For the final layer, fill to about the midpoint or higher of the extension. This layer is important because after compaction, the top of the layer must be equal to or above the top of the mold. If it is not the test must be done over c. d. e. f. g. Repeat step b

7. Remove the extension and base plate. With the steel straight edge level off the sample so it is even with the top and bottom of the mold. Take care not to create divots in the sample during this process 8.

9. Determine the weight (W2) of the soil and mold or plus base plate (not the extension). Use scale sensitive to 0.1 lb. to determine this weight. 10. With the aid of the extruder, remove the sample from the mold. moisture tin. 12. Determine the weight (Wtinesoil) of the moisture tin and soil. 13. Place the moisture tin and soil in the oven over night to dry 14. Repeat steps 5 through 13 for each of the remaining test specimens 15. Determine the weight (Wtin-dry soi) of the tin and dry soil for each test specimen.

Calculations Moisture Content Weight of water Weight of dry sample Moisture content- 100 otin Moist Unit Weight weight of moist soil volume of mold Moist unit weight- 4 Dry Unit Weight Dry unit weight weight of dry soil volume of mold or 100 Plot the compaction curve, yd vs. w. Draw a best-fit curve, using a French curve so the curve is smooth. Determine the optimum water content and maximum dry unit weight from the curve. Plot the zero air voids curve on the same plot as the compaction curve. Use a French curve and plot at least 4 points to get the general shape of the curve. Plot the Zero Air Voids Curve: 100

Sample Engineer Date Moisture Content Can No Weight of tin, Wn Weight of tin wet soil, W Weight of tin +dry soil, W Moisture content, w 2 4 Unit Weight Weight of mold, W, ht of mold soil, W Volume of mold, V Unit weight, y Dry unit weight, Yo Compaction Curve Optimum water content Maximum dry density Water Content(%)