AN EVALUATION OF COMPACTION CONTROL OF GRANULAR BASE AND SUBBASE AGGREGATES
An introductory proceudre for the determination of compaction of granular and earth materials was implemented on all contracts in the 1980 construction season. The new procedures called for compaction acceptance on a lot basis; a lot is subdivided into four equal sublots and one random density test is taken on each sublot. A granular lot was acceptable for compaction if the mean of the four tests within a lot was at least 100% of the corresponding One Point Proctor (OPT) maximum density, provided that no single test resulted in less than 95% of the maximum density. A special provision using the "control strip" density for target was incorporated into four contracts in 1980, in order to evaluate the validity of this method of compaction control of granular bases and subbases. The target density for compaction is the economically achievable maximum density, obtained through closely controlled compaction on a test strip provided that this achieved density is equal to or greter than 95% of the OPT maximum density. Acceptance of each specified course is made where the mean dry density of the four tests within a lot is 97% or greater than the target and where each test is 95% or greater than the target density. This report deals with the statistical analysis and evaluation of the compaction data collected during the 1980 construction season, for both the special provision and the introductory procedure. As a result of the analysis, it is concluded that the acceptance requiremtns for compaction by the special provision are too lenient, when compared with the statistical dispersion of the actual data. The analysis also proved that full compliance for acceptance, recommended by the introductory procedure, could not be met. Some 13% to 16% of the compacted lots had less than 100% OPT densities. It has also been noted that neither of the acceptance procedures fully recognize the variability of densities within the lot. To resolve the above shortcomings, a new acceptance plan is proposed, which would be applicable to both mehtods of compaction control. The proposed mehtod called "the percentage within tolerance" (or the percentage defective) sets the acceptance level to be a certain portion of the lot having less than the acceptable minimum degree of compaction. It is recommended that the control strip technique be employed to establish the target density in those cases where the OPT maximum density value cannot be acheived.
Ontario Ministry of Transportation & Communic, CanEngineering Materials Office, 1201 Wilson Avenue
Downsview, ONo M3M 1J8, Canada
- Barsvary, A K
- MACLEAN, M
- Publication Date: 1981-3
- Pagination: 65 p.
- TRT Terms: Aggregates; Compaction; Density; Granular bases; Statistical analysis; Subbase materials; Test procedures; Validity
- Subject Areas: Construction; Data and Information Technology; Geotechnology; Highways; I52: Construction of Pavements and Surfacings;
- Accession Number: 00335520
- Record Type: Publication
- Report/Paper Numbers: EM-39
- Files: TRIS
- Created Date: Nov 23 1981 12:00AM