Hillsborough County Florida is using a mix of expanding polyurethane foam and conventional cement grout as a more cost effective means of filling sinkholes. Officials say the mix uses 30 to 40% less grout adding up to a 30% cost savings. The article in the Tampa Tribune did not indicate the contractor or product name that they are using but apparently several agencies in California and other states are using the same material. Story via ASCE SmartBrief.
Articles
The Curious Case of No. 57 Stone
The American Society for Testing and Materials, or ASTM, No. 57 stone is often used as sub base fill material below road surfaces and buildings. It is a fragmented stone with angular edges and is regularly utilized as a drainage layer when used with geotextile fabric. Although the material is touted by many as "self-compacting," excess voids left from zero compactive effort in locations with little confinement may not eliminate the possibility of future settlement. What happens when the environment above the No. 57 stone causes it to settle?
[Editor] Read on for the answer to this interesting question in the case of settlement of a structure at the University of North Carolina at Chapel Hill. The contributed article by Katherine Witt describes how URETEK Mid-Atlantic used their high-density polyurethane resin to stabilize the No. 57 stone beneath a settled foundation as well as lift the surrounding slab back into place. [/Editor]
Geologic Hazards
40 Foot Sinkhole in Tenn. Stadium Endzone
A large 40 foot wide by 40 foot deep sinkhole opened up just outside the endzone of Austin Peay State University’s Governors Stadium in Tennessee. The stadium is currently undergoing upgrades for next year’s football season. Sinkholes are not unexpected on Austin Peay campus, and the video below shows one example of how the University has actually incorporated the remediated sinkholes into the landscaping. Representatives from the University and the contractor expect the sinkhole will be filled without any problems.
[Updated 1/19/2015] Click through for the video since I can’t figure out how to turn off the auto-play on this one. [/Updated]
Geologic Hazards
Giant sinkhole threatens to swallow house, forces family (and its pets) to flee
A backyard-sized sinkhole opened up recently behind a Windermere, Florida home, causing the home to be deemed unsafe. The residents said one of their kids was enjoying a hammock in the area just the night […]