Chief inspector, Prescott, AZ
Consulting civil engineer, Scottsdale, AZ
Pages: 6 Published: Jan 1998
Over ten years ago, the City of Prescott, Arizona, first installed a non-shrink slurry as a controlled low-strength trench backfill material. Since then, the process has become a standard for all utility trench installations. The non-shrink slurry backfill is a controlled low-strength portland cement concrete product with a compressive strength of 120 to 150 psi (827 to 1034 kPa) in 30 to 60 days and has a 0-inch slump. Prior use of aggregate backfills resulted in a failure rate of greater than 80 %. The City has re-excavated numerous trenches filled with the slurry material and successfully removed the slurry from various pipe systems including water, sewer, natural gas, electric, telephone, cable, and fiber optic installations. The City of Prescott now requires this controlled low-strength slurry in all trench restoration work. The failure rate over a ten-year period has been less than 1 %.
non-shrink slurry, CLSM, flowable fill, 0-inch slump, performance, re-excavation
Paper ID: STP13076S