CATEGORY 300 DRAINAGE SECTION 314 — FLOWABLE BACKFILL
314.01 Description
Furnish, haul, and place flowable cement stabilized backfill material. When specified, use for utility cut backfill, pipe backfill, or for filling abandoned pipes.
314.02 Materials
Controlled Low Strength Material 902.16
314.02.01 Fillers. When required, fillers shall be natural aggregates with a maximum size of
3/4 in. and may include sands. Bottom ash shall not be used as filler.
314.02.02 Components. Toxic and deleterious components shall not be used in the backfill
mixture. The mixture shall have a 28 day, unconfined compressive strength of at least 100 psi based on the manufacturer's certification. Certification shall include the actual test data for each mixture to be used.
314.02.03 Analysis. Chemical analysis of the fly ash used in the mixture shall conform to U.S.
EPA EP Toxicity Standards. Whenever the coal source is changed or replenished, and when fly ash from a different source is used, conduct an analysis of the fly ash from each stockpile. Submit the results of the analysis to the Engineer for approval prior to using the mixture.
314.03 Construction
Place the material according to the manufacturer’s recommendations or as directed by the Engineer. Backfill utility trenches full depth to the top of the subgrade. Fill all voids during the backfill operation. Protect the backfilled utility cut from freezing and traffic for 24 hours. Wait at least 24 hours after backfilling is complete and approved by the Engineer before beginning the paving operations. Fill abandoned pipes with backfill after each end of the pipe has been adequately plugged. Refer to 303.03.06. Cut two holes into the plug at the upstream end and pump backfill into the pipe through one of the holes until the pipe is filled. Keep and submit detailed records of all flowable backfill placed. Include the source of the fly ash, the date placed, the location, depth, and the quantity used. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
314.04 Measurement and Payment
necessary to complete the work. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS Flowable Backfill will be measured and paid for at the Contract unit price per cubic yard. The payment will be full compensation for all material, labor, equipment, tools, and incidentals 315 — INFILTRATION TRENCHES CATEGORY 300 DRAINAGE SECTION 315 — INFILTRATION TRENCHES
315.01 Description
Install infiltration trenches as specified.
315.02 Materials
Riprap 901.02, Class I Geotextile Section 919, Class as specified Polyvinyl chloride profile wall drain pipe Section 905 Stone M 43, No. 2
315.03 Construction
Do not place infiltration trenches in service until all of the contributing drainage area has been stabilized and approved. Restrict heavy equipment and traffic from the proposed infiltration trench location.
315.03.01 Excavation. Remove excavated material from the trench site. Ensure that trench walls
and bottom are free of protruding objects that could damage the geotextile. When necessary, slope the trench walls. Ensure that the bottom dimensions and stone depth are as specified. Roughen the side walls of the trench. Grade the bottom of the trench flat. For excavated material, refer to 402.03.01.
315.03.02 Installation. Place geotextile on the sides of the trench and the top of the No. 2 stone.
Do not cover the bottom of the trench. The geotextile for the sides of the trench shall overlap the top geotextile by 6 in. to 8 in. Extend the top geotextile the full width and length of the trench. All longitudinal joints in the top geotextile shall overlap at least 6 in. The upstream roll shall overlap the downstream roll by at least 2 ft, for a shingled effect. Place an observation well vertically in the longitudinal center of each infiltration trench. Use 6 in. diameter slotted perforated polyvinyl chloride profile wall drainpipe (PPWP). Place the pipe on a base plate at the bottom of the trench. Cap the well using a threaded PVC fitting and a vandal proof sewer cap. Set the cap 6 in. above ground, and mark the depth of the trench on the cap. Provide a plastic collar with ribs to prevent rotation of the well when removing the cap. When soil capping is used, construct the observation well using perforated PPWP within the No. 2 stone and non-perforated pipe through the soil capping. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS