Compaction Samyog.pptx

Compaction

1. DIFFENTIATION BETWEEN PROCTOR COMPACTION TEST AND MODIFIED PROCTOR COMPACTION TEST AND EMPERICAL RELATION FOR COMPACTION TEST Prepared by:- Samyog Khanal (13/077) Central Department of Geology Tribhuvan University Engineering Geology [email protected] Submitted to:- Ranjan Kumar Dahal, PhD, PostDoc, M.ASCE Associate Professor Central Department of Geology Tribhuvan University Kirtipur, Kathmandu, Nepal

2. 1) Introduction In general, compaction is the process of densifying soil by removing air , which needs mechanical energy . The dry unit weight of a soil is used to determine the degree of compaction. As the moisture content rises, the dry unit weight after initial compaction rises. The optimum moisture content is typically defined as the moisture content at which the greatest dry unit weight is achieved. The Proctor compaction test is the laboratory procedure often used to determine the ideal moisture content and maximum dry unit weight of compaction (Proctor, 1933)

3. Figure 1:- Principles of Compaction At a moisture content w=0, γ = γ d (w=0) = γ 1 At w= w 1, γ = γ 2 The dry unit weight at this moisture content is γ d(w=w1) = γ d(w = 0) + Where γ = moist unit weight γ d = dry unit weight  

4. 2) Importance of Compaction Compaction Increases the Strength of soil Increases the bearing capacity of foundation Increases the Strength of soil Increases the Stability of slope of embankments Figure 2:- Flow chart presenting importance of Compaction

5. 3) Discussion a) Type of Compaction test Standard Proctor Compaction test (SPCT) The procedure for the standard Proctor test is elaborated in ASTM Test Designation D-698 (ASTM, 2007) and AASHTO Test Designation T-99 (AASHTO, 1982). Modified Proctor Compaction test (MPCT) This is revised version of Standard Proctor Compaction test sometimes is referred to as the modified Proctor test (ASTM Test Designation D-1557 and AASHTO Test Designation T-180).

6. b) Differentiate between SPCT and MPCT SPCT Mold Volume= 944 cm 3 (ft 3 ) Mold Diameter= 101.6 mm (4in) Mold Height= 116.43mm (4.584in) Weight of Hammer= 2.5 Kg (6.5lb) Height of drop= 304.8mm(12in) Number of Soil Layer= 3 Number of blows/layer= 25blows Compaction Energy= 594 KN-m/m 3 MPCT Mold Volume= 944 cm 3 (ft 3 ) Mold Diameter= 101.6 mm (4in) Mold Height= 116.43mm (4.584in) Weight of Hammer= 4.54 Kg (10lb) Height of drop= 457mm(18in) Number of Soil Layer= 5 Number of blows/layer= 25blows Compaction Energy= 2700 KN-m/m 3

7. Figure 3:- Standard Proctor test equipment: (a) mold; (b) hammer

8. Figure 4:- Comparison between standard Proctor hammer (left) and modified Proctor hammer (right) (Courtesy of Braja M. Das, Henderson, Nevada)

9. c) Empirical relation for compaction test For the both test, The moist unit weight of compaction γ , can be calculated as γ = W/V (m) Where, W= Weight of Compacted Soil in the mold. V (m) = Volume of the mold (944cm 3 or 1/30ft) The dry unit weight can be calculated as γ d= Where (w % )= Percent of moisture content  

10. 4) Conclusion The modified Proctor test increases the compactive effort, resulting in an increase in the maximum dry unit weight of the soil. A drop in the ideal moisture content coincides with an increase in the maximum dry unit weight. The maximum dry unit weight and ideal moisture content are greatly influenced by the distribution of grain sizes , the form of the soil grains, the specific gravity of the soil solids, and the quantity and kind of clay minerals present.

11. 5) References DAS, B. M., “PRINCIPLES OF GEOTECHNICAL ENGINEERING 7 th edition ,” Cengage Learning 2006 2010, P 144–155. AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS (1982). AASHTO Materials, Part II, Washington, D.C. AMERICAN SOCIETY FOR TESTING AND MATERIALS (2007). Annual Book of ASTM Standards, Vol 04.08, West Conshohocken, Pa.

12. Thank you ! Have Nice Day