078210 — Tamped Fill

210.01 Description

Compact the embankment and backfill materials by means of mechanical tampers or vibratory compactors. Use this method of compaction wherever materials cannot be adequately compacted by other approved methods.

210.02 Materials

Refer to Section 916.

210.03 Construction

After approval has been given by the Engineer, place approved material in horizontal layers not exceeding 6 in. loose depth over the entire area. Tamp and uniformly compact the material using mechanical tampers or vibratory compactors. Refer to 204.03.04 for moisture and compaction. When backfilling around abutments, retaining walls, culverts, utilities, or other structures, prevent any wedging action against the structure. When placing backfill against existing slopes, excavate benches or steps. Place the backfill in horizontal layers as described above and wide enough that there is a horizontal berm of thoroughly compacted material behind the structure at all times for a distance at least equal to the height of the structure remaining to be backfilled, except insofar as undisturbed material protrudes into this space. Tamping may be required over additional widths when the material cannot be adequately compacted by other methods. When installing structures below subgrade in embankments, place the tamped fill to a depth of 1 ft over the top of the structure. In excavation sections, extend the tamped fill to the surface of the finished earthwork.

210.04 Measurement and Payment

Compacting embankments and backfills by mechanical tampers or vibratory compactors will not be measured but the cost will be incidental to the pertinent items specified in the Contract Documents. 211 — GEOSYNTHETHIC STABILIZED SUBGRADE USING GRADED AGGREGATE BASE CATEGORY 200 GRADING SECTION 211 — GEOSYNTHETHIC STABILIZED SUBGRADE USING GRADED AGGREGATE BASE

211.01 Description

Furnish and place a layer of geotextile and 12 in. of graded aggregate base to bridge unstable material and minimize the use of undercutting. Use this item only when specified or directed. In extremely unstable areas, the Engineer may increase the thickness of the graded aggregate base material.

211.02 Materials

Graded Aggregate Base 901.01 Geotextile for Subgrade Stabilization-Class ST Section 919 Securing Pins or Staples 919.03

211.03 Construction

211.03.01 Test Strip. In extremely unstable areas, the Engineer may direct that a test strip be

constructed to determine the thickness of aggregate layer required to stabilize the area. The Engineer will determine the depth of aggregate to be used in the test strip. Construct the test strip at least 100 ft in length and at least one lane wide. The results of the test strip will be used to determine the thickness of aggregate required for subsequent construction.

211.03.02 Grade Preparation. Cut the area where the geotextile is to be placed to the depth

shown or as directed. Bring the area to the specified line, grade, and cross section. Provide a grade that is smooth as practical and free of debris. Minimize construction traffic on the grade. Remove ruts by reshaping, but do not overwork the grade. Have the grade approved prior to placement of the geotextile. Maintain adequate surface drainage as specified in 208.03.03. The Engineer may waive compaction and moisture requirements for the underlying soil. 211.03.03 Geotextile Placement. Place geotextile on the prepared surface for the full width of the area to be treated. In areas where longitudinal underdrain is to be placed, place the geotextile up to the edge of the proposed longitudinal underdrain trench, but not where the trench is to be excavated. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS