Office of Capital Projects FAQ's

What is the useful life of flowable fill when delivered to a site?

Research indicates that the useful life is about 2.5 hours. Set time can be altered in the mix design. Proper planning should eliminate any issues with using old or expired materials.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:02pm

Q1333
Is there a delay or lag time with using flowable fill for backfilling operations?

Most ready-mix producers can handle the flowable fill delivery needs of City departments. Concrete base can be poured as soon as it sets up, usually between two and four hours.

Use of flowable fill requires a contract with a concrete company as well as a delivery notice (same as for concrete). The mix design specified by the City can be made by any concrete plant in the county.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:01pm

Q1334
Are there any requirements for ordering flowable fill for irregular shaped holes?

Any hole, no matter what shape, has to be rough measured for material. After that, the concrete dispatcher can calculate the amount of flowable fill needed.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:01pm

Q1335
When using flowable fill, can trucks be washed out the same way as concrete trucks are when excess material is ordered?

The truck can wash its chute out right in the hole. There is minimal wash-out with flowable fill material.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:01pm

Q1336
How difficult is hand digging in a trench backfilled with flowable fill?

Any strengths between 50 PSI and 100 PSI are very easy to hand dig and would also need less re-excavation.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:00pm

Q1337
When excavating in flowable fill trenches, is it difficult to locate existing utilities without damage?

When flowable fill is designed correctly, utilities which are not encased are easier to find.

Dirt is not a stable material, especially when wet, and when excavation causes it to move it can result in damage to utilities that are not well encased.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:00pm

Q1338
How does the use of flowable fill affect the ability to accurately trace/find water main breaks/leaks?

Leaks travel along pipes, making them hard to find.

Flowable fill causes the area near a leak to be less permeable, making it more likely for the water to push up through the soil, instead of traveling along the pipe.

This process makes it easier to find a leak.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 2:00pm

Q1339
Is there difficulty using test rods to find leads when flowable fill is used?

Test rods are hard to pound in where flowable fill is used and it takes longer to find and repair leaks. The proper mix design from 50 PSI to 100 PSI eliminates the need to pound in the test rods.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 1:59pm

Q1340
Should test holes be drilled when flowable fill is used?

Yes, test holes should be drilled for air relief when undermining to ensure flowable fill is filled properly.

Routine undermining from trench or excavation should be cut out following the City's roadway repair restoration guidelines (see specifications here.)

Contractors should contact the Division of Engineering & Construction at 216.664.2379 for special instructions if a lot of undermining is encountered.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 04/08/2015 - 7:16pm

Q1341
Is a Certificate of Compliance necessary for the use of flowable fill?

Yes. It must come from a plant with a current Certificate of Compliance demonstrating the ability of the mix design to meet specified requirements.

The certificate must contain the name of supplier, date, contract number and mix design data on each delivery ticket. Certificates over a year old will not be accepted.

From:
Division of Engineering & Construction
Category:
Streets and Transportation

Last updated: 03/25/2015 - 1:59pm

Q1342

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