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.
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Mudjacking, also called slab jacking, concrete lifting, concrete raising, and slab leveling, is the traditional method of fixing damaged concrete highways and bridge approach panels. The process was developed in the 1930s and involves pumping “mud” (everything from clay, sand, and loam, to Portland cement, fly ash, lime, casting plaster, and hot asphalt have been used) beneath concrete slabs that have become uneven, sunken, and/or pulled away from bridge approaches due to soil erosion and/or the soil being compacted or compressed from the sheer weight of the slab. Mudjacking involves drilling holes in the concrete and pumping “mud” and pressure beneath to lift the slab to its original place and keep it there. [Editor] Click th rough for the rest of the press release. [/Editor]

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