Example Recommendations for Compaction Specifications

1 Example Recommendations for Compaction Specifications The following examples are provided as general reference guidance for geotechnical engineers and civil engineers to use when developing their Recommendations or Compaction Specifications for the design phase. I. Compaction Control Specifications : A. Conventional Option with Site Control This recommendation applies the standard Compaction (M-D control) spec to the moisture-density curves the site is compacting on, and keeps the select lab reference curves as minimum density reference standards. Compact [select from 8-12 ] loose lifts to a minimum of [select from 90% - 98%] of the maximum dry-density and within [select dry % to wet %, or wet of optimum range] of the optimum moisture content on the moisture-density curve of the site lift at full Compaction , as generated by each soil-compactor-lift thickness combination used for each fill lift.

2 The compacted dry density shall also meet or exceed [select %] of a maximum dry-density from a moisture-density relation representative of the [select ASTM D-698 or D-1557, AASHTO T-99 or T-180, or Tx114] lab Compaction test. Compact each lift with the minimum # of passes producing full asymptotic Compaction with the compactor used on site. Each lift specific moisture-density curves shall be self-verifying with actual moisture-density data measured from the compacted lifts. Lift-specific moisture-density curves shall be located upon each change in soil index properties, lift thickness, or compactor, from full-scale test pads on site or an equivalent self-verifying source. Obtain a lab-based reference curve upon each change in soil index properties. Lab-based curves must be verifiably located along a line-of-optimums representative of [select lab test] and vary only with soil property variation.

3 B. Conventional Option without Site Control This recommendation applies the standard Compaction (M-D control) spec to a lab test moisture-density curve unrelated to the site curve, to establish a target M-D range that does not align with optimum M-D at the site. Compact [select from 8-12 ] loose lifts to a minimum of [select from 90% - 98%] of a maximum dry-density and within [select dry % to wet %] of an optimum moisture content from a moisture-density relation representative of the [select ASTM D-698 or D-1557, AASHTO T-99 or T-180, or Tx114] lab Compaction test. Obtain a new moisture-density curve upon each variation in soil index properties. Each lab-based curve must be verifiably located along a line-of-optimums representative of [select lab test] and vary only with soil property variation.

4 Obtain moisture-density curves through SSCE information services provided by ESOL ( ), or an approved equivalent. Based Compaction Specifications (with or without Site Control):Compact fill in controlled lifts sufficient to achieve the following minimum physical properties: [select one or more fill properties based on design requirements], each with a minimum factor-of-safety of [select FS based on design analysis]. Use, maintain and control, compactor-soil-lift combinations sufficient to achieve these properties for each lift as approved by the engineer. Compact each lift with the minimum # of passes producing full asymptotic Compaction with the compactor used on site. Control Compaction at a minimum of [select from 90% - 98%] maximum dry density and within [select dry % to wet %] of optimum moisture content on the moisture-density curve of the site lift as generated by each soil-compactor-lift thickness combination used for each fill lift.

5 Lift specific moisture-density curves shall be self-verifying with actual moisture-density data measured from the compacted lifts. Maintain real-time records of compacted physical properties for each constructed lift using SSCE information services provided by ESOL ( ) or approved equivalent. Compacted properties shall be verified from periodic Shelby-tube test cores extracted every [select #] CYs from compacted lifts.