LARIMER COUNTY RURAL AREA ROAD STANDARDS

Appendix D – Construction StandardsSection D.2 Revisions to CDOT Standards Specifications for Road and Bridge Constructioncontrolled rate addition of the needed moisture. Final moisture content of the mix, priorto compaction, shall not exceed the optimum moisture content of the mix by more than 2percent nor by less than the optimum by more than 4 percent. Should the naturalmoisture content of the soil be above the specified range, aeration of the soil may berequired prior to addition of the fly ash.308.05 Compaction. Compaction of the mixture shall begin immediately after final mixing ofthe fly ash and be completed within one hour following addition of water to the fly ash. Thematerial shall be sprinkled as necessary to maintain the optimum moisture. Compaction of themixture shall begin at the bottom and shall continue until the entire depth of mixture is uniformlycompacted to a specified density.All non-uniform (too wet, too dry, or insufficiently treated) areas which appear shall be correctedimmediately by scarifying the areas affected, adding or removing material as required,reshaping and recompacting. The surface of the course shall be maintained in a smoothcondition, free from undulations and ruts, until other work is placed thereon or the work isaccepted.The stabilized section shall be compacted to the extent necessary to provide the densityspecified below:For fly ash treated subgrade, existing subbase ormaximumexisting base that will receive subsequent subbaseor base courses.For fly ash treated subbase or base that willmaximumreceive surface course.Not less than 95 percentdry density (ASTM D-698)Not less than 96 percentDry density (ASTM D-698)In addition to the requirements specified for density, the full depth of the material shown on theplans shall be compacted to the extent necessary to remain firm and stable under constructionequipment. After each section is completed, tests as necessary will be made by the Engineer.If the material fails to meet the density requirements, the Engineer may require it to be reworkedas necessary to meet those requirements or require the Contractor to change his constructionmethods to obtain required density on the next section. Throughout this entire operation theshape of the course shall be maintained by blading, and the surface, upon completion, shall besmooth and in conformity with the typical section shown on the plans and to established linesand grades. Blading should be terminated within two hours after blending of the fly ash. Shouldthe material, due to any reason or cause, lose the required stability, density, and finish beforethe next course is placed or the work is accepted, it shall be reprocessed, recompacted andrefinished at the sole expense of the Contract. Reprocessing shall follow the same pattern asthe initial stabilization, including the addition of fly ash.308.06 Finishing and Curing. After the final layer or course of the treated subgrade, subbase,or base has been compacted, it shall be brought to the required lines and grades in accordancewith the typical sections.The resulting base surface shall be thoroughly rolled with a pneumatic tire roller and “clipped”,“skinned”, or “tight bladed” by a motor grader to a depth of approximately ¼ inch, removing allLarimer County Rural Area Road Standards Page D-12October 22, 2007