EXPERIMENT 5 FIELD DENSITY TEST: SAND REPLACEMENT METHOD (PREPARED BY : MUHAMMAD MUNSIF AHMAD)

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1 1.0 OBJECTIVE EXPERIMENT 5 FIELD DENSITY TEST: SAND REPLACEMENT METHOD (PREPARED BY : MUHAMMAD MUNSIF AHMAD) To determine the in-situ density of fine and medium rained soil. 2.0 INTRODUCTION In most specifications for earthwork, the contractor is instructed to achieve a compacted field dry unit weiht of 90 to 95% of the maximum dry unit weiht determined in the laboratory by either the standard or modified Proctor test. This is a specification for relative compaction, which can be calculated based on the laboratory maximum dry density and in-situ density of soil. The specification for field compaction based on relative compaction or on relative density is an end-product specification. The contractor is expected to achieve a minimum dry unit weiht reardless of the field procedure adopted. Sand replacement method covers the determination in-situ of the density of natural or compacted fine and medium rained soil for which a sand pourin cylinder is used in conjunction with replacement sand. It is suested that this method to be applied to layers of soil not exceedin 150 mm in thickness. 3.0 TEST EQUIPMENT 3.1 Pourin cylinder 3.2 Calibratin container 3.3 Balance, readable to Metal tray, lass plate. 3.5 Moisture content apparatus 3.6 Metal tray with 100 mm hole in the centre. 3.7 Replacement sand. 100% passin a 600um sieve and retained on the 63um sieve. 12

2 4.0 PROCEDURES Calibrations 1. Fill the pourin cylinder so that the level of the sand in the cylinder is within about 15 mm of the top. Find its total initial mass, m1, to the nearest 1 and always use the same initial mass for every calibration. Maintain this constant throuhout the tests for which the calibration is used. 2. Allow a volume of sand equivalent to that of the excavated hole in the soil (or equal to that of the calibratin container) to run out. Close the shutter on the pourin cylinder and place the cylinder on a plane surface, e.. the lass plate. 3. Open the shutter on the pourin cylinder and allow sand to run out. Do not tap or otherwise vibrate durin this period. When no further movement of sand takes place in the cylinder, close the shutter and remove the cylinder carefully. 4. Collect the sand on the lass plate that had filled the cone of the pourin cylinder and determine its mass, m2, to the nearest Repeat these measurements at least three times and calculate the mean value of m2. 6. Determine the internal volume, V (in ml), of the calibratin container 7. Place the pourin cylinder concentrically on the top of the calibratin container after it has been filled to the constant mass, m1, as specified in 1. Keep the shutter on the pourin cylinder closed durin this operation. Open the shutter and allow the sand to run out. Do not tap the pourin cylinder or otherwise vibrate it durin this period. When no further movement of sand takes place in the cylinder, close the shutter. Remove the pourin cylinder with the sand remainin in it and determine their combined mass, m3, to the nearest Repeat these measurements at least three times and calculate the mean value of m3. Procedure 9. Expose a flat area, approximately 450mm square, of the soil to be tested and trim it down to a level surface, preferably with the aid of the scraper tool. Brush away any loose extraneous material. 13

3 10. Lay the metal tray on the prepared surface with the hole over the portion of the soil to be tested. Usin this hole as a pattern, excavate a round hole, approximately 100mm in diameter and the depth of the layer to be tested up to a maximum of 150mm deep. Do not leave loose material in the hole and do not distort the immediate surround to the hole. 11. Carefully collect all the excavated soil from the hole and determine its mass, mw, to the nearest 1. Remove the metal tray before placin the pourin cylinder in position over the excavated hole 12. Place a representative sample of the excavated soil in an airtiht container and determine its moisture content, w. 13. Place the pourin cylinder, filled to the constant mass, m1, as specified in 1, so that the base of the cylinder covers the hole concentrically. 14. Open the shutter and allow sand to run out; durin this period do not vibrate the cylinder or the surroundin area. 15. When no further movement of the sand takes place close the shutter. Remove the cylinder and determine its mass, m4, to the nearest 1. 14

4 5.0 RESULTS Calibration Mean mass of sand in cone (of pourin cylinder) (m 2) Volume of calibratin container (V) ml Mass of sand (+cylinder) before pourin (m 1) Mean mass of sand (+cylinder) after pourin (m 3) Mass of sand to fill calibratin container (m s = m 1 - m 3 - m 2) Bulk density of sand ρ a = m s/v M/m 3 Test Number Mass of wet soil from hole (m w) Mass of sand (+cylinder) before pourin (m 1) Mass of sand (+cylinder) after pourin (m 4) Mass of sand in hole (m b = m 1 - m 4 - m 2) Ratio m w/m b Bulk density ρ = (m w/m b) x ρ a (M/m 3 ) Moisture content container no. Moisture content (w) (%) Dry density ρ d = (100ρ)/(100 + w) (M/m 3 ) 15

5 6.0 DISCUSSION/ EVALUATION/ EXERCISES a) Calculate the in-situ dry density of soil b) Explain the term relative density. c) What is the required relative density to be achieved at site? d) State the problem factors that affect the accuracy of experiment? 7.0 CONCLUSION Comment on the objective and the results obtained from the experiment 16

Density of Granular Material by Modified Sand-Cone Method for Thin Layers

Density of Granular Material by Modified Sand-Cone Method for Thin Layers 1. Scope: This test is for determining in-place density of granular materials that have a total thickness of 3 or less. 2. Apparatus: