97-2003 THE STANDARD AND THE MOD°F°ED PROCTOR TESTS

download 97-2003 THE STANDARD  AND  THE MOD°F°ED PROCTOR TESTS

of 12

  • date post

    22-Nov-2014
  • Category

    Documents

  • view

    110
  • download

    3

Embed Size (px)

Transcript of 97-2003 THE STANDARD AND THE MOD°F°ED PROCTOR TESTS

THE STANDARD PROCTOR AND THE MODFED PROCTOR TESTS Purpose: This laboratory test is performed to determine the relationship between the moisture content and the dry density of a soil for a specified compactive effort. The compactive effort is the amount of mechanical energy that is applied to the soil mass. Two types of compaction tests are routinely performed: (1) The Standard Proctor Test, and (2) The Modified Proctor Test. Reference: ASTM D 698 - Standard Test Methods for Laboratory Compaction ASTM D 1557 - Standard Test Methods for Laboratory Compaction Equipment: Proctor mould with a detachable collar assembly and base plate. Drop rammer a) Standard Test: 24.5N rammer falling 0.305m b) Modified Test: 44.5N rammer falling 0.46m Sample Extruder. A sensitive balance. Straight edge. Squeeze bottle Mixing tools such as mixing pan, spoon, trowel, spatula etc. Moisture cans. Drying Oven 10.#4 sieve, Graduated cylinder, Test Procedure (1) Depending on the type of mold you are using obtain a sufficient quantity of air-dried soil in large mixing pan. For the 101,6mm mold take approximately 4,5kg, and for the 152,4mm mold take roughly 6,75kg. Pulverize the soil and run it through the # 4 sieve.

(2) Determine the weight of the soil sample as well as the weight of the compaction mold with its base (without the collar) by using the balance and record the weights. (3) Compute the amount of initial water to add by the following method: (a) Assume water content for the first test to be 8 percent. (b) Compute water to add from the following equation: water to add (in ml) = (soil mass in grams) 8/ 100 or add approximate amount of water to increase the moisture content by about 5%. (4) Measure out the water, add it to the soil, and then mix it thoroughly into the soil using the trowel until the soil gets a uniform color (See Photos B and C). (5) Assemble the compaction mold to the base, place some soil in the mold and compact the soil in the number of equal layers specified by the type of compaction method employed (See Photos D and E) Place the first portion of the soil in the Proctor mould as explained in the class and compact the layer applying 25 blows. (6) Scratch the layer with a spatula forming a grid to ensure uniformity in distribution of compaction energy to the subsequent layer. Place the second layer, apply 25 blows, place the last portion and apply 25 blows.The number of drops of the rammer per layer is also dependent upon the type of mold used. The drops should be applied at a uniform rate not exceeding around 1.5 seconds per drop, and the rammer should provide uniform coverage of the specimen surface. Try to avoid rebound of the rammer from the top of the guide sleeve. (7) The soil should completely fill the cylinder and the last compacted layer must extend slightly above the collar joint. If the soil is below the collar joint at the completion of the drops, the test point must be repeated. (Note: For the last layer, watch carefully, and add more soil after about 10 drops if it appears that the soil will be compacted below the collar joint.) (8) Carefully remove the collar and trim off the compacted soil so that it is completely even with the top of the mold using the trowel. Replace small bits of soil that may fall out during the trimming process (See Photo F). (9) Weigh the compacted soil while its in the mold and to the base, and record the mass (See Photo G). Determine the wet mass of the soil by subtracting the weight of the mold and base.

(10) Remove the soil from the mold using a mechanical extruder (See Photo H) and take soil moisture content samples from the top and bottom of the specimen (See Photo I). Fill the moisture cans with soil and determine the water content. (11) Place the soil specimen in the large tray and break up the soil until it appears visually as if it will pass through the # 4 sieve, add 2 percent more water based on the original sample mass, and re-mix as in step 4. Repeat steps 5 through 9 until, based on wet mass, a peak value is reached followed by two slightly lesser compacted soil masses.

Calculations: (1) Calculate the moisture content of each compacted soil specimen . (2) Compute the wet density in grams per cm3 of the compacted soil sample by dividing the wet mass by the volume of the mold used.

(3) Compute the dry density using the wet density and the water content determined in step 1. Use the following formula:

where: w = moisture content in percent divided by 100, and = wet density in grams per cm3. (4) Compute the dry unit weight in kN per m3 .

(5) Plot the dry unit weight values on the y-axis and the moisture contents on the x-axis. Draw a smooth curve connecting the plotted points. (6) On the same graph draw a curve of complete saturation or zero air voids curve. The values of dry density and corresponding moisture contents for plotting the curve can be computed from the following equation:

where: yd= dry unit weight of soil (kN/m3) Gs = specific gravity of the soil being tested (assume 2.70 if not given) yw = unit weight of water (kN/m3)

S = moisture content in percent for complete saturation.(7) Identify and report the optimum moisture content and the maximum dry unit weight..

Data And Graphics For Modified Proctor Test

MODIFIED PROCTOR TEST Dry Unit Density (g/cm3)1,873 1,910 1,803 1,699 1,641

Dry Unit Weight (kN/m3)18,37 18,74 17,69 16,67 16,10

Moisture Content w(%)9,3 12,8 15,5 18,7 21,1

Specific Gravity2,64 2,64 2,64 2,64 2,64

Dry Unit Weight d(kN/m3) S=70%19,17 17,47 16,34 15,19 14,42

S=80%19,82 18,21 17,13 16,02 15,27

S=90%20,35 18,83 17,80 16,72 16,00

S=100%20,79 19,36 18,38 17,34 16,63

Ydmax=18,52kN/m3 and WOPTMUM=9,8% are obtained from The Dry unit curve.Data And Graphics For Standard Proctor Test STANDART PROCTOR TEST Dry Unit Weight (g/cm3)1,691 1,715 1,755 1,747 1,685 1,619

Dry Unit Weight (kN/m3)16,59 16,82 17,22 17,14 16,53 15,88

Moisture Content w(%)9,3 11,8 14,3 17,6 20,8 23

Dry Unit Weight d(kN/m3) Gs S=70%2,64 2,64 2,64 2,64 2,64 2,64 19,17 17,92 16,82 15,57 14,51 13,87

S=80%19,82 18,64 17,60 16,38 15,36 14,72

S=90%20,35 19,24 18,25 17,08 16,08 15,46

S=100%20,79 19,75 18,80 17,68 16,72 16,11

Ydmax=17,20kN/m3 curve.

and WOPTMUM=15,1% are obtained from The Dry unit

SAND CONE TEST

Purpose:This test method describes the procedure for determining the density of soil in place.

Reference: AASHTO T 191 (Sand Cone)

Equipment Sampling tools - hammer, chisel, trowel, large spoon, banister brush.

Containers - two 2.3 L size mason jars for which the tare weights are known. Balance - 0.1 g accuracy Sand Cone Density Apparatus(Figure1) - consisting of a double cone assembly having a cylindrical valve between the cones with an orifice 12.7 mm in diameter. The upper conewill be large enough to serve as a hopper to hold the density sand. Density Sand - prepare a supply of air dried clean flowing sand which passes the 2.00 mm sieve and is retained on the 900 mm sieve. Thoroughly mix and preweigh 5000 g samples and store in a clean dry place.

Procedure1. Select the site to be tested at random or where sample for proctor has been taken. 2. Scrape smooth and remove all loose material at the location to be tested. 3. Start a small hole in the centre with a hammer and chisel. 4. Carefully enlarge the hole outwards and downwards with small hand tools until sufficient material has been removed to fill the two 2.3 L mason jars. 5. Exercise extreme care in removing the material so as not to cause a disturbance to surrounding material. Do not project the hole below the level of the material to be tested. 6. Place all the material removed from the hole in the mason jars except Stone particles larger than 18 mm. These stones will be replaced in the hole during the volume measurement with density sand. The sealed jars will be taken to the lab and weighed to the nearest gram and the tare weight subtracted. The result will be recorded as "weight of material removed." 7. Carefully place and centre the sand cone device over the test hole with the valve closed. 8. Place the 5000 g of density sand into the storage hopper of the sand cone device. 9. Turn on the valve. 10. If stone particles are to be replaced in the hole, allow a small quantity of sand to run into the hole, close the valve, lift the apparatus, and partially imbed these particles into the sand. Replace the device, turn on the valve, allow the sand to run until the test hole and funnel are completely filled, and turn off the valve. 11. Remove the apparatus and remove the sand from the test hole and place in a large cloth bag along with other used sand for later reclaiming.

12. Weigh the unused sand in the hopper to determine the amount of sand used in the test. This weight of sand will be used to obtain the volume of hole and funnel. 13. Remove the soil cement mixture from the two mason jars and mix thoroughly together and obtain a representative sample for moisture determination. 14. Place sample in a suitable tared pan and weigh. 15. Dry sample carefully to a constant weight. 16. Weigh sample and pan after cooling. 17. The difference between the wet and dry weights will be recorded as "weight of moisture" and dry weight less weight of pan will be recorded as "weight of dry sample."

Figure 1 Sand Cone Test Device

Calculation : W1: The weight of the jar,the cone , sand W2: The weight of the Moist soil excavted from hole

Wc: The weight of sand to fill the cone only W3: The weight of the jar,the cone and remaining sand in the jar W4: The Dry Weight of soil w: water content(%)

y d(sand): Dry unit weight of the sand used y d: Dry unit weight of soil W4=W2/(1+w/100) V=(W1 W3- Wc)/y d(sand) y d=W4/VData For Sand Cone