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Polyurethane Concrete Slab-Jacking VS Conventional “Mud”-Jacking - page 2 / 3





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Polyurethane-Conventional Comparison


Recommended Material:

The American Pressure Grouting & Mudjacking Association and Black-Jack Grout Pumps Inc. recommend the following material for use in any Slab-Jacking or Concrete Lifting application with consideration to:

Cost (material & equipment) Compression Strengths Flow under pressure Availability State and Federally Accepted Recyclable

CEMENTITIOUS GROUT is by far the most user friendly and versatile grouting material. (Portland Cement, Fly-Ash, Sand, water, Bentonite & admixtures as required)

The cost of the polyurethane equipment and materials are approximately 4 to 5 time the cost of conventional grouting equipment and materials. Compression strengths are easily controlled by adding or subtracting Portland cement to grout. Average compression strengths of polyurethane are 80-100 psi, while average compression strengths of Portland cement, Fly-Ash, and Sand are 1,500-4,000 psi. Higher compression strengths are critical for heavy bearing loads. Slab deflection has been observed when using lower strength materials. Flow of material under pressure is close to equal; both polyurethane and the above grout mix have extremely high lubricity therefore penetrating the smallest area. Portland cement, Fly-Ash, Sand, and Grout can be purchased and delivered by most any ready- mix company in bulk/bagged or mixed. Distributor availability of polyurethane is limited when compared to ready-mix companies. Grout costs average between $96.00-$128.00 per cubic yard(prices are subject to change). Portland cement/fly-ash/sand grout has been accepted and used by State and Federal agencies. At present polyurethane has been used as well; however municipalities within the study area indicated polyurethane to be cost prohibitive. In the state of Missouri on highway 54 near Mexico, polyurethane was injected and resettling occurred after a short period of time. At present most State and Federal Department of Transportation recycle Portland cement pavement, polyurethane being a non-cementious material, separation will increase cost of the re-cycling processing. End results of any material used for Slab-Jacking is completely dependent on the supporting materials of the Portland cement pavement, however both polyurethane and grout can be injected into soil, peat moss, aggregates (when applicable) for stabilization.

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August 17, 2010

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