Attachment F - Self-compacting fill.pdf

VA R O C K Y M O U N TA I N R E G I O N A L M E D I C A L C E N T E R — A U R O R A , C O

Squeegee Specification Info Sheet — Map 32 Self-compacting fill for two sink pits — response support for RFI Item 7

ITEM

Map 32 — Self-Compacting Fill

RFI

Item 7 — Map 32

LOCATION

Landscaped rock-mulch area adjacent to a building

PIT 1

Approx. 30 CY

PIT 2

Approx. 200 CY

TOTAL IN PLACE

Approx. 230 CY

SOW basis (Map 32): “Two sink pits recently formed and have since stopped progressing. Contractor shall fill pits as appropriate with squeegee or similarly approved self compacting fill and restore top of sink pits to match surrounding area.”

This sheet confirms the material, gradation, and placement method on that basis.

Suggested RFI response — paste-ready:

“Squeegee conforming to the AASHTO M 43 / ASTM D448 Size No. 8 gradation in Section 2 of this sheet is approved for Map 32, subject to contractor submittal of the supplier gradation before delivery and placement by the method in Section 5, including lift densification and post-placement top-up.”

1 — APPROVED MATERIAL: APPROVE BY GRADATION, NOT BY NAME

The approved material is clean, open-graded crushed stone or crushed gravel meeting Size No. 8 below, sold locally as “squeegee.” Approval attaches to the gradation, not to the trade name alone. Colorado suppliers use “squeegee” inconsistently — for small round rock, for sifted crusher fines, and for fine pea gravel. The contractor must submit the supplier’s gradation report (ASTM C136 / AASHTO T 27) showing compliance before delivery. No material is approved on name alone.

In Colorado usage, Colorado State University Extension describes squeegee as sifted “crusher fines” that packs down more than pea gravel, and Raptor Materials (northern Colorado) describes squeegee rock as specially graded crushed stone used for drainage, pipe bedding, surface stabilization, and erosion control. Those descriptions support the use here, but they do not replace a gradation submittal.

2 — GRADATION — AASHTO M 43 / ASTM D448, SIZE NO. 8

Sieve Size (mm) Percent passing by weight

1/2 in 12.5 mm 100

3/8 in 9.5 mm 85–100

No. 4 4.75 mm 10–30

No. 8 2.36 mm 0–10

No. 16 1.18 mm 0–5

Test method: ASTM C136 / AASHTO T 27. This is the standard No. 8 band routinely described by quarries and state agencies as open-graded, self-compacting aggregate.

Squeegee Spec Info Sheet — Map 32 / RFI 7 Page 1 of 3

3 — PHYSICAL REQUIREMENTS

Composition: Clean, hard, durable crushed stone or crushed gravel. Angular to sub-angular particles are preferred because they interlock.

Cleanliness: Free of clay, organics, debris, and other deleterious material. Essentially low fines — maximum 5% passing the No. 200 sieve for the clean No. 8 option.

Durability (if requested by the COR): Los Angeles abrasion and soundness in accordance with CDOT Section 703 /

ASTM C33.

Strength: Not applicable. Squeegee is an unbound aggregate, so no compressive strength (psi) applies to it. If a strength is required for a pit, that work is flowable fill — see Section 7.

4 — WHAT IS NOT APPROVED — EQUIVALENCY RULE

Rounded pea gravel is not equivalent by default. Rounded particles shift and do not interlock like angular No. 8 stone.

Use only if the COR specifically approves it.

Crusher-fines / “breeze” alternate: May be considered only if the submitted gradation is 3/8-in minus, well-graded, and COR-approved. It is not interchangeable with No. 8 by name alone.

Any “similar” fill under the SOW must be submitted with its gradation and material description and approved before placement.

Topsoil, unscreened excavation spoil, construction debris, and material with clay or organics are not approved.

CRITICAL — “Self-compacting” does not mean 95% compaction. The term is a trade description, not a performance guarantee. Dumped clean gravel and crushed rock is typically only about 80% of maximum index density (ASTM D4253 / D7382), as reported in Underground Construction (Feb. 2016, “‘Self-Compacting’ Soils”). Placement settlement of about 8% should be expected for No. 8 stone. That is why Section 5 is a method specification, not “dump and leave.”

5 — PLACEMENT AND COMPACTION METHOD

1. Confirm the void first: Verify limits and depth, remove loose debris and unsuitable material, and check whether the void extends under any building, pavement, or utility (see Hold Point, Section 6).

2. Place in lifts: Maximum 12-in loose lifts where access allows.

3. Densify every lift: Rod, flood, vibrate, or plate-compact each lift until no visible further densification occurs. Choke or saturate to help material flow into voids where appropriate and where drainage allows.

4. Surcharge: Mound slightly above final grade to allow for settlement.

5. Top up: Return after initial settlement, add material as needed, re-densify, and only then restore the surface rock mulch to match the surrounding area.

6 — PERFORMANCE AND ACCEPTANCE

Nuclear density (nuclear-gauge) testing is not applicable to open-graded No. 8 stone. Acceptance is by: (1) approved gradation submittal, (2) observation of lift densification with no visible further movement, (3) probing for firmness and voids, and (4) a documented post-placement top-up visit.

HOLD POINT / SAFETY: If either pit is found to extend under a building, pavement, or utility, or if the void is still progressing, stop — do not just fill. Notify the COR for geotechnical evaluation. Filling under this sheet is on the SOW basis that the pits have stopped progressing and are in a landscaped area, not under pavement or a structure.

Squeegee Spec Info Sheet — Map 32 / RFI 7 Page 2 of 3

7 — APPROVED ALTERNATE: FLOWABLE FILL (CLSM)

Use controlled low-strength material / flowable fill under VA Section 31 23 23.33 where lift compaction cannot be verified — in deep, inaccessible, or undermined voids, and especially if Pit 2 (approx. 200 CY) extends under any structure, pavement, or utility.

Permanent flowable fill: Minimum 300 psi compressive strength at 28 days.

Excavatable flowable fill: Maximum 200 psi at 1 year (machine excavatable) or maximum 100 psi at 1 year (hand-tool excavatable).

Substitution requires direction from the COR / Resident Engineer before placement. Do not substitute on the contractor’s election alone.

8 — SUBMITTALS AND QA CHECKLIST

9 — QUANTITY AND ORDERING NOTE

In-place quantity is approx. 230 CY (30 CY + 200 CY). As an estimate only, allow about 8–10% extra for settlement and top-up — about 250 CY total. Confirm the supplier’s CY-to-ton conversion and bulk unit weight when ordering; conversions vary by source.

Sources AASHTO M 43 / ASTM D448-12 (2022), Table 1, Size No. 8; AASHTO #8 Stone Specs sheet (Capitol Flexi-Pave, citing quarry / state agency definition); Colorado State University Extension, Ask Extension FAQ on rock mulch / squeegee (Larimer / Douglas County); Raptor Materials, Squeegee product page; Underground Construction, Feb. 2016, “‘Self-Compacting’ Soils”; VA Section 31 23 23.33, Flowable Fill (Whole Building Design Guide, WBDG); CDOT Standard Specifications, Section 703, Aggregates; ASTM C33.

Disclaimer: This is an information sheet prepared to support an RFI response. It is not a geotechnical design. Final approval of material, alternate, and placement rests with the Contracting Officer’s Representative (COR) / Resident Engineer.

Supplier name and material source☐

Gradation report (ASTM C136 / AASHTO T 27) showing No. 8 compliance☐

Material description — crushed/angular or rounded, washed or unwashed☐

Quantity calculation: 30 CY + 200 CY = 230 CY, plus settlement allowance (see Section 9)☐

Placement method statement (lifts, densification, top-up)☐

Photos before, during, and after placement☐

Top-up visit record, with quantity added and final grade confirmed☐

Squeegee Spec Info Sheet — Map 32 / RFI 7 — VA Aurora, CO Page 3 of 3

VHAECHKAWAKS

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