G. L. Hoffman, ~Gaylord Cumberledge,' and W. C. Koehler,' Laboratory Compaction Test Methods and Results Compared with Attainable Field Densities on Subbase Materials REFERENCE: Hoffman, G. L., Cumberledge, Gaylord, and Koehler, W. C., "Laboratory Compaction Test Methods and Results Com pared, with Attainable Field Den sities~ ou Sobbase Materials," Journal of Testing and Evaluation, JTEVA, Vol. 4, No. 3, May 1976, pp. 167-175. ABSTRACT: With the extensive use of aggregate material in high- way construction (primarily subbase) in Pennsylvania, the Pennsyl- vania Depart ment o f T ransportation (PennDOT) initiated an in- depth analysis of results of laboratory and field compaction tests on aggregates. This study determined what field and laboratory tests are best correlated to produce the optimum compaction con- trol technique for subbase materials. Results of approximately 500 sand cone and nuclear field den- sities in cru shed limestone, gravel, and sla g material at 17 con- struction s ites throughout the state are summarized and compared. Laboratory density tests on ma terial fro m each of these field test sites include vibratory, standard moisture-density, modified mois- Regression correlation analyses are performed between maximum attainable field and la boratory densities. E stimating linear equa- tions for predicting relationships b etween field and laboratory maximum den siti es are developed and their significance is dis- cussed. KEY WORDS: pavement base s, field strength, density (mass/vol- ume), impact strength, compacting, vibration With the extensive use of aggregate material in highway con- struction (primarily subbase) in Pennsylvania, the Pennsylvania Department of Transportation (PennDOT) initiated an in-depth statistical analysis of laboratory compaction test methods and results as compared with attainable field densities of subbase materials. This study determined which field and laboratory tests are best correlated to produce the optimum compaction control technique for subbase and similar dense, graded materials. Sev- eral test site locations with various subbase material types were chosen throughout Pennsylvania for this study. The location of these sites along with other relevant data is given in Table 1. Subbase Material Types and Gradation The subbase materials selected for this study were three types: gravel, limestone, and slag. These materials are readily available Presented at th e Symposium on Graded Aggregate Bases and Base Materials, Annual Meeting of the American Society of Testing and Materials, 10 Dec. 1974, Atlanta, Ga. 'Soils research engineer, assistant engineer of tests, and engineer of tests, respectively, Bureau of Materials, Testing and Research, Pennsyl- vania Department of Transportation (PennDOT) , Harrisburg, Pa. 17120. Mr. Koehler is a member o f ASTM. and widely used in Pennsylvania. There were 17 sources of the subbase material. Figure 1 indicates field test site locations along with the respective type of subbase material. All gradations were within the limits for Pa. No. 2A subbase material (see Table 2) according to PennDOT specifications 1416 1-8 Limestone 11-13 Slag 9 Slag 14-17 Grave l 10 Granulated Slag FIG. 1 Field test site locations and respective subbase types. (Form 408). Material samples were obtained from individual field density test locations at a particular site. All samples from this site were then mixed in the laboratory, and the particle size distribution of this mix was checked for conformance with the above specification. No visual difference of material type or gradation was noted within a specific test area. Field Test Methods Within an hour after each roller pass, two field density mea- surements were taken by three different methods along with deflection measurements with the Road Rater ~. The density test locations are schematically indicated in Fig. 2. The average of the two density measurements by each method within a roller pass area was used in the statistical analyses. The thickness of lifts, number of lifts and roller passes, and the type of com- paction equipment were also noted. One roller pass was desig- nated as one pass forward and one pass back over the same nuclear gage in accordance with ASTM Tests for Density of Soil and Soil -Aggregate in Place by Nuclear Methods (D 2922- 71), and then two types of sand cone tests, in accordance with ASTM Test for Density of Soil in Place by the Sand-Cone Method (D 1556-68), were performed adjacent to one another at the 1 6 7 Copyright by ASTM Int'l (all rights reserved); Wed Mar 28 22:27:47 EDT 2012 Downloaded/printed by UNIVERSITY TEKNOLOGI MALAYSIA pursuant to License Agreement. No further reproductions authorized.
