Section 614 — Flowable Backfill

Description

614.01This work consists of constructing flowable backfill of controlled low strength material.

Material

614.02Conform to the following Subsections: Chemical admixtures 711.03 Flowable backfill aggregate 703.15 Hydraulic cement 701.01 Pozzolans 701.03 Water for cementitious materials 725.01(a)

Construction Requirements

614.03Composition of Mix. Design a well -graded, flowable, self -leveling mix. Design a mix with a 7-day compressive strength between 75 and 250 pounds per square inch according to ASTM D4832. Verify the mix design with trial batches prepared from the same sources proposed for the mix. Submit the following for approval at least 21 days before production:

(a)Type and source of aggregates;

(b)Type and source of cement;

(c)Type and source of pozzolans, if used in the mix;

(d)Type and supplier of admixtures, if used in the mix;

(e)Mix proportions;

(f)Commercial certifications for each material contained in the mix;

(g)Target values for water to cementitious material ratio and slump; and

(h)Compressive strength at 7 days.

614.04General. Excavate and backfill according to Section 209. Do not place flowable backfill in contact with aluminum or aluminum -coated structures. Do not use flowable backfill above the top of subgrade.

614.05Mixing and Placing Flowable Backfill. Mix flowable backfill by pugmill, rotary drum, or other approved mixer to obtain a uniform mix. Place flowable backfill in a uniform manner that prevents voids or segregation in the backfill. Maintain the temperature of flowable backfill to at least 50 °F at the time of placement. Protect the material from freezing for 24 hours after placement. If backfilling around culverts and other structures, place flowable backfill so that the structure does not float or shift. Bring the backfill up evenly on all sides of the structure. Maintain correct alignment of structures by use of straps, soil anchors, or other approved methods of restraint. If placing flowable backfill at or below an ambient temperature of 35 °F, perform the work according to Subsect ion 552.07(a) . Wait at least 4 hours before backfilling over flowable backfill.

614.06Acceptance. Material for flowable backfill will be evaluated under Subsections 106.02 and 106.03, and 106.04 if tested for compressive strength according to ASTM D4832. Construction of flowable backfill will be evaluated under Subsection 106.02. Excavation and backfill will be evaluated unde r Section 209.

Measurement

614.07Measure the Section 614 pay items listed in the bid schedule according to Subsection 109.02 and the following as applicable: When measuring flowable backfill by the cubic yard, measure in the hauling vehicle.

Payment

614.08The accepted quantities will be paid at the contract price per unit of measurement for the Section 614 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 . Section 615. — RESERVED