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            Chapter 5
          
        
        
          PolyLEVEL
        
        
          ®
        
        
          Polyurethane Foam and Resin
        
        
          
            CHAPTER 5
          
        
        
          POLYLEVEL
        
        
          ®
        
        
          POLYURETHANE FOAM AND RESIN
        
        
          
            CHAPTER 5
          
        
        
          POLYLEVEL
        
        
          ®
        
        
          POLYURETHANE FOAM AND RESIN
        
        
          
            5.1 Summary Description
          
        
        
          The PolyLEVEL product line consists of
        
        
          polyurethane foams and resins for use in a
        
        
          wide range of geotechnical and structural
        
        
          applications. The more commonly used
        
        
          products are two-part urethanes that expand
        
        
          into rigid foam to fill voids, stabilize concrete,
        
        
          and lift concrete. The product is injected at the
        
        
          interface between the concrete slab and the
        
        
          subgrade soils
        
        
          (Figure 5.1.a)
        
        
          . Variations in the
        
        
          formulas of the two-part foams allow for uses in
        
        
          even more specific applications, as mentioned in
        
        
          Section 5.2. Outside of the general offerings of
        
        
          two-part products, single-part, non-expanding
        
        
          PolyLEVEL resin is injected deep into loose
        
        
          soil as a binder material, thereby stabilizing the
        
        
          soil from further consolidation/densification, or
        
        
          allowing vertical excavations to be made.
        
        
          Polyurethane is not a new material. The
        
        
          chemistry of polyurethanes was discovered and
        
        
          patented in 1937 and has been used extensively
        
        
          for three quarters of a century in a variety of
        
        
          products and materials. Polyurethanes are
        
        
          best known to the public in the form of flexible
        
        
          foams; i.e., upholstery cushions, mattresses,
        
        
          caulking, weatherstripping, vehicle door and
        
        
          dash moldings, tires for toddler bikes and
        
        
          wheelborrows, etc. Spray foam insulation
        
        
          and foam filler within shells of watercraft are
        
        
          examples most similar to the line of two-part
        
        
          PolyLEVEL products.
        
        
          Polyurethane foam is created by the reaction
        
        
          of a diisocyanate (the “A” or “Iso” side) with
        
        
          a polyol (the “R” or “Resin” side) to form a
        
        
          urethane linkage. Diisocynates are organic
        
        
          compounds that are specifically manufactured
        
        
          to react with polyols. The A side varies little
        
        
          between polyurethanes of similar product lines
        
        
          or use groups. Polyols are simply alcohols with
        
        
          multiple hydroxyl groups. The polyols and other
        
        
          additives within the R side may vary significantly
        
        
          between products to control characteristics
        
        
          such as color, density and speed of reaction.
        
        
          Figure 5.1.a
        
        
          Rendering of PolyLEVEL foam
        
        
          injection beneath concrete pavement