Polyurethane Concrete Slab-Jacking VS Conventional “Mud”-Jacking
After 30 years of field experience in pressure grouting/mud-jacking/slab-jacking, American Pressure Grouting and Mudjacking Association partnered with leading grout pump manufacturer Black-Jack Grout Pumps Inc. to analyze materials being used in the industry. An extensive 2 year comparison study of Polyurethane verses Classic mix design suggests a much more limited role for Polyurethane products than conventional wisdom would allow.
History: There has always been a desperate search for a stable lubricant to be used for pressure grouting and slab jacking that is both affordable and available throughout the United States and the World.
As concrete lifting equipment developed, a very inexpensive un-stable lubricant was discovered. Subsequently Topsoil/Black dirt/Mud was recommended for use by early equipment manufacturers. The simple name was created “Mud-Jack”
Only after many years of close study, the end results were staggering. Topsoil/Black dirt/Mud being organic in nature began to breakdown over a short period of time. Confidence in the reliability of Slab- Jacking was diminishing. Research showed that the contractor was often at fault. In many cases the contractor cut corners by reducing or eliminating Portland cement or simply performed the procedure incorrectly.
Understanding and recognizing the benefits of Slab-Jacking, regulations were implemented at a State and Federal government level. American Pressure Grouting and Mud-Jacking Association at present is the only private self-governing body. Members recognize the importance of these simple standards in order to preserve the integrity of Slab-Jacking and bolster Industry confidence in the future. (See www.apgma.com)
Part of the 2 year study was determining the most stable, reliable, affordable, and available material for Slab-Jacking. The results of the study were collected by certified technicians, board directors, and Municipal /Field Engineers. Physical inspection of actual projects were done in Illinois, Wisconsin, and Missouri. Other state climatic or geometric conditions do vary however, but similar results can be expected.
When Slab-Jacking or Pressure Grouting, perform a standard organic content test prior to use. Some materials which certainly require testing are Top Soil, Pond Sand, Limestone by-products, and most natural unconditioned/processed aggregates (Consult testing engineers in your area). The percentage of organic content in any mix should never exceed standards set forth by APGMA. Finished grouts/polyurethanes should be tested to ensure adequate compression strengths and non-shrink properties prior to use. Once a material has been determined as satisfactory, strict quality control should be maintained at all times.
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August 17, 2010