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1 Student Manual lesson 2 Density Theory lesson 2. 2-1. Version 1/15 2 1 Student Manual lesson 2 Density Theory Learning Outcomes Describe the difference between compaction and density and wet & dry density Calculate unit weight Describe the Proctor and LBR Tests and their use Identify and describe material classifications for embankment construction 2-2. Version 1/15 2 2 Student Manual lesson 2 Density Theory Terminology What is the difference between COMPACTION & DENSITY. 2-3. The contractor uses compaction, (a process) to achieve density (a product). Compactive effort is a measure of the mechanical energy applied to a soil mass. In the field, compactive effort is the number of passes or coverages of the roller of a certain type and weight on a given volume of soil Version 1/15 2 3 Student Manual lesson 2 Density Theory Terminology Wet Density vs. Dry Density Wet Density = Total Density = (Total Weight)/(Total Volume).

2 = (Solids+Water+Gas)/(Total Volume). Dry Density = Dry Weight / Total Volume = (Solids+Gas)/(Total Volume). = (Solids)/(Total Volume). 2-4. Wet Density the weight of soil and water occupying a unit volume Dry Density the weight of just the soil solids occupying a unit volume Version 1/15 2 4 Student Manual lesson 2 Density Theory Density DENSITY = WEIGHT / VOLUME. VOLUME = H x L x D. DENSITY = W / (H x L x D) L. D. H. W. 2-5. Density is the ratio of the mass of a substance to its volume, expressed, for example, in units of grams per cubic centimeter or pounds per cubic foot. The density of a pure substance varies little from sample to sample and is often considered a characteristic property of the substance. Density often is taken as an indication of how heavy a substance is. Iron is denser than cork, since a given volume of iron is more massive (and weighs more) than the same volume of cork. It is often said that iron is heavier.

3 Than cork, although a large volume of cork obviously can be more massive and thus be heavier ( , weigh more) than a small volume of iron. Weight is the measure of the force of gravity on a body. Since the weights of different bodies at the same location are proportional to their masses, weight is often used as a measure of mass. However, the two are not the same; mass is a measure of the amount of matter present in a body and thus has the same value at different locations, and weight varies depending upon the location of the body in the earth's gravitational field (or the gravitational field of some other astronomical body). A given body will have the same mass on the earth and on the moon, but its weight on the moon will be only about 16% of the weight as measured on the earth. One pound of weight, or force, is the force necessary at a given location to accelerate a one-pound mass at a rate equal to the acceleration of gravity at that location (about 32 ft per sec ).

4 Version 1/15 2 5 Student Manual lesson 2 Density Theory Version 1/15 2 6 Student Manual lesson 2 Density Theory Exercise CLASS PROBLEM. What is the density of the cube? 5 ft. 3 ft. DENSITY = W / V. 2 ft. SCALE Weight = 200 lbs. 2-6. Math Problem Work Area Version 1/15 2 7 Student Manual lesson 2 Density Theory Learning Outcomes Compaction is considered a _____ when compared to density. Density is considered the _____ when compared to compaction. 2-7. Version 1/15 2 8 Student Manual lesson 2 Density Theory Learning Outcomes Wet density is the weight of _____ occupying a unit volume. Dry density is the weight of _____. occupying a unit volume. 2-8. Version 1/15 2 9 Student Manual lesson 2 Density Theory Theory What does A represent? Proctor Test Curve B. DENSITY. What does B represent? DRY. A. % MOISTURE. 2-9. Version 1/15 2 10 Student Manual lesson 2 Density Theory Theory Maximum Density (B). at Can the Contractor achieve Optimum Moisture Content (A) 98% outside the dashed lines?

5 100% B Target Area 98%. Dry Density Where will it be easiest for (pcf) Just Right the Contractor to achieve density? A. % Moisture 2-10. Version 1/15 2 11 Student Manual lesson 2 Density Theory Moisture Sensitivity of Soils Which of these two is affected more by water? CLAYEY SOIL. PCF. Increasing Moisture SANDY SOIL. PCF. Increasing Moisture 2-11. Version 1/15 2 12 Student Manual lesson 2 Density Theory Maximum Density (Proctor). MODIFIED PROCTOR STANDARD PROCTOR. FM 1 T-180 - Moisture Density AASHTO T 99 - Moisture Density Relations of Soils Using 10-lb. Relations of Soils Using ( ) Rammer and 18-inch ( ) Rammer and 12-inch (305- (457-mm) Drop mm) Drop DIFFERENCES. Rammer Weight - 10 lb. Rammer Weight - lbs. Drop Height - 18 inches Drop Height - 12 inches Use spacer disc in mold No spacer disc in mold Use 6 inch molds Use 4 inch molds 56 blows/layer; 5 layers 25 blows/layer; 3 layers 2-12. The FDOT uses two types of Moisture Density Relation tests: Standard - AASHTO T-99, which employs the use of a lb.

6 Rammer dropped from a height of 12. inches. Specimens are prepared in 4 inch molds. NOTE: This is the method typically used for obtaining Proctor values on embankment and structure backfill materials. Modified - FM 1 T-180, which employs a 10 lb. rammer dropped from a height of 18 inches. Specimens are prepared in 6 inch molds and a spacer disk used in the bottom of the mold. NOTE: This is the method typically used for obtaining Proctor values for project base, subgrade and MSE wall materials. As road construction equipment and methods improved, it became apparent that construction methods were outdistancing testing methods. In an effort to have Proctor testing be more representative of what was being done in the field, the Modified Proctor was adopted by the FDOT. The Modified Proctor requires substantially more effort in the compaction process than the Standard method. Version 1/15 2 13 Student Manual lesson 2 Density Theory Proctor Applicability MODIFIED PROCTOR STANDARD PROCTOR.

7 Method typically used on Method typically used on FDOT. FDOT projects for base, projects for embankment &. subgrade and MSE wall structure backfill materials. backfill materials. Generally, requirement is Generally, requirement is 98% of Maximum Density 100% of Maximum Density (some isolated cases 95%, (some isolated cases 95%, such as MSE Walls). such as plastic and metal pipe). 2-13. Version 1/15 2 14 Student Manual lesson 2 Density Theory Limerock Bearing Ratio (LBR). WHAT IS THE LBR? The ratio of the bearing capacity of the material being tested to the bearing capacity of reference limerock PURPOSE OF TEST. The Limerock Bearing Ratio Test is useful for determining whether limerock and other soils used for base and subgrade, meet the minimum strength requirements in the plans. 2-14. The standard penetration resistance for a typical crushed limerock in Florida has been standardized to 800 psi. The LBR result is expressed as a percent, without the percent sign.

8 The LBR test is a Florida revision to the California Bearing Ratio test procedure. Version 1/15 2 15 Student Manual lesson 2 Density Theory Limerock Bearing Ratio (LBR). BEARING CAPACITY of MATERIAL_ x 100.. LBR = (REFERENCE LIMEROCK) 800 psi LBR vs. % MOISTURE. 200. 100. LBR VARIES WITH THE 80. 60. MOISTURE AT THE TIME OF L. B 40. COMPACTION. R. 20. 10. 7 8 9 10 11. % MOIST. 2-15. Version 1/15 2 16 Student Manual lesson 2 Density Theory Limerock Bearing Ratio (LBR). 200. AT PENETRATION. 150. DATE COMPACTED. MOLD NO. 203 100. WATER ( ) 6%. WET WT. + MOLD (GM) 11789. 50. WET WT. + MOLD (LBS.) 40. WT. OF MOLD (LBS.) 30. WET WT. (LBS.) WET UNIT WT. ( ) 20. DRY UNIT WT. ( ) 15. LBR 81. BEGIN SOAK. END SOAK DRY UNIT WT. ( ). TIME OF TEST. MOISTURE DETERMINATION. CAN NO. 9. CAN + WET SOIL (GM) 130. CAN + DRY SOIL (GM) 129. WT. WATER (GM) WT. CAN (GM) 128. WT. DRY SOIL (GM) 127. MOISTURE CONTENT (%) 126. 125. 6% 7% 8% 9% 10%2-16.

9 WATER CONTENT, %. Version 1/15 2 17 Student Manual lesson 2 Density Theory Exercise Using the following graph, answer these questions: 1. What is the Maximum Density? 2. What is the Optimum Moisture? 3. What is the Moisture Range for 98% of the Maximum Density? 4. What is the LBR? 2-17. Version 1/15 2 18 Student Manual lesson 2 Density Theory Exercise 200. 150. AT PENETRATION. 100. 50. 40. 30. 20. 15. DRY UNIT WT. ( ). 130. 129. 128. 127. 126. 125. 6% 7% 8% 9% 10% 2-18. WATER CONTENT, %. Version 1/15 2 19 Student Manual lesson 2 Density Theory Learning Outcomes What is the method number for the Standard Proctor? What is the method number for the Modified Proctor? 2-19. Version 1/15 2 20 Student Manual lesson 2 Density Theory Learning Outcomes The standard penetration resistance for the LBR. has been standardized to _____. The LBR value is NOT affected by moisture at the time of compaction. True or False 2-20.

10 Version 1/15 2 21 Student Manual lesson 2 Density Theory Embankment Utilization Design Std. 505 -Sheet 1. Flexible Pavement 2-21. Version 1/15 2 22 Student Manual lesson 2 Density Theory Embankment Utilization Design Std. 505 Sheets 2 & 3. Rigid Pavement with Treated Permeable Base (2). Rigid Pavement with Asphalt Base (3). 2-22. Version 1/15 2 23 Student Manual lesson 2 Density Theory Embankment Utilization Design Std. 505 Sheet 4. Rigid Pavement with Special Select Option 2-23. Version 1/15 2 24 Student Manual lesson 2 Density Theory Soil Classification Design Std. 505 (Combination of Sheets 1 - 4). Symbol Soil Classification AASHTO M-145. S Select A-1, A-3, A-2-4**. S+ Special A-3** with Min. Average Lab Permeability Select of 5x10-5 cm/sec as per FM 1-T215. P Plastic A-2-5, A-2-6, A-2-7, A-4, A-5, A-6, A-7 (All with LL<50). H High Plastic A-2-5, A-2-7, A-5 or A-7 (All with LL>50). M Muck A-8. 2-24. ** Certain types of A-2-4 materials are likely to retain excess moisture and may be difficult to dry and compact.