POUR-IN-PLACE

The term bitumen is used in France to designate petroleum products, as in Great Britain and Germany. In the United States on the other hand, the equivalent material is designated by the expression asphalt-cement . In France, asphalt is a mastic, a mixture of bitumen and powdered minerals, poured in place. This mixture can be either natural or reconstituted by an industriai process. Asphait (French meaning) is utilized on roads, particularly in urban centers as well as for sidewalk surfacing. 

The product contains 12.6% phosphoms and has an OH number in the 450 mg KOH/g range. Fyrol 6 is used to impart a permanent Class 11 E-84 flame spread rating to rigid foam for insulating walls and roofs. Particular advantages are low viscosity, stabiHty in polyol—catalyst mixtures, and outstanding humid aging resistance. Fyrol 6 is used in both spray foam, froth, pour-in-place, and slab stock. 

CeUular polymers are also used for pipe and vessel insulation. Spray and pour-in-place techniques of appHcation are particularly suitable, and polyurethane and epoxy foams are widely used. Ease of appHcation, fire properties, and low thermal conductivity have been responsible for the acceptance of ceUular mbber and ceUular poly(vinyl chloride) as insulation for smaller pipes. 

Monofunctional, cyclohexylamine is used as a polyamide polymerization chain terminator to control polymer molecular weight. 3,3,5-Trimethylcyclohexylamines ate usehil fuel additives, corrosion inhibitors, and biocides (50). Dicyclohexylamine has direct uses as a solvent for cephalosporin antibiotic production, as a corrosion inhibitor, and as a fuel oil additive, in addition to serving as an organic intermediate. Cycloahphatic tertiary amines are used as urethane catalysts (72). Dimethylcyclohexylarnine (DMCHA) is marketed by Air Products as POLYCAT 8 for pour-in-place rigid insulating foam. Methyldicyclohexylamine is POLYCAT 12 used for flexible slabstock and molded foam. DM CHA is also sold as a fuel oil additive, which acts as an antioxidant. StericaHy hindered secondary cycloahphatic amines, specifically dicyclohexylamine, effectively catalyze polycarbonate polymerization (73). 

Table 7. Properties of Poured-in-Place Polyurethane Resilient Surfaces...

For other recreational surfaces, such as mnning tracks, the installation techniques are quite different. Most are poured-in-place. An interlocking tile technique may be employed for tennis courts. In all cases, adequate provision for weathering and water drainage is essential. In general, the resiHent surfaces are installed over a hard base (see Fig. 4) that contains the necessary curbs to provide the finished level. Outdoors, asphalt is the most common base, and indoors, concrete. A poured-in-place polyurethane surface (14) is mixed on-site and cast from at least two components, an isocyanate and a filled... 

Expansire cements are hydrauHc cements designed to expand rather than shrink on curing, as do standard Pordand cements. They are defined in ASTM C845 and are used to control and reduce shrinkage cracks in large poured-in place stmctures. 

Lightweight concrete is usually sprayed on, but may be troweled or formed-in-place using reinforcing mesh. Pneumatically applied material is about 20% heavier than poured-in-place lightweight concrete. As with all concretes, moisture creates a corrosive condition at the surface of the steel. Protective coating of the substrate surface is needed to protect against corrosion. 

Las Vegas, Nv., 20th-23rd Oct. 1996, p. 179-89. 43C6 LOW DENSITY ALL WATER-BLOWN RIGID FOAM FOR POUR-IN-PLACE APPLICATIONS Kaplan W A Neill P L Staudte L C Brink C J Stepan Co. 

The dimensional stability of low density, water blown rigid PU foams for pour-in-place thermal insulation applications was improved by the use of a phthalic anhydride based polyester polyol containing a dispersed cell opening agent. The foam systems obtained allowed some of the carbon dioxide to be released through the cell windows immediately after filling of the cavity, and to be rapidly replaced by air. Studies were made of the flowability, density, open cell content, dimensional stability, mechanical properties, thermal conductivity and adhesion (particularly to flame treated PE) of these foams. These properties were examined in comparison with those of HCFC-141b blown foams. 21 refs. 

Although hot-poured sulphur concrete is very suitable for poured-in-place and precast applications, the material cannot at this time be press-molded and is thus not amenable to high speed/ high volume production of small blocks. Although a potentially large market exists for blocks of this kind, such as tile and brick, it was not until the late 1970s that an attempt to develop a cold mix/press-mold sulphur based technology was successful. 

The Sulphur Innovations Ltd. material, Sulfurcrete, has been sold commercially as pre-cast products (pipeline weights, median barriers, parking curbs, etc.) and poured in place as road patches, floor slabs, retaining walls, etc. (20). 

Asarco tested components of sulfur concrete, both precast and poured in place, in corrosive environments of sulfuric acid. Favorable endurance of these samples led to a full-scale cooperative demonstration project. The project selected was the rehabilitation of an electrolytic zinc cellhouse basement floor of approximately 21,000 square feet. 

S.I.L. uses standard concrete transit mixer trucks modified to provide gas or propane heat to the mix drum to prepare mixes for both precast and poured-in-place work. Since 1977 several poured-in-place field trials have been completed and numerous projects in the Calgary area have now been constructed. Precast products that have been marketed include parking curbs, pipeline weights, sewer pipe, median barriers, and sidewalk slabs. 

Once mixed, the material can be handled using any equipment suitable for asphalt mixtures. As consistency can be varied from the equivalent of zero slump concrete to that of a sloppy mortar, the molten mix can be used for precast, slip-formed, extended or poured-in-place applications. 

Silicone rubber has both excellent low temperature and high temperature properties. It can withstand temperatures up to 315°C and workable at -65°C. Poor performance with low tear strength and abrasion resistance limit their use in most applications. Liquid silicone compounds LTV which are room temperature vulcanizable are useful for small repairs and sealing application and have been used for poured-in-place gaskets. 

Process and Equipment. Rigid polyurethane foam processes use Ihe same high or low pressure pumping, metering, and mixing equipment for flexible foams. Subsequent handling of the mixture is determined by the end product desired. Processes include lamination, pour-in-place, molding, bun stock, box loams, and spray. 

The bulk of the ngid polyurethane and polyisocyanurate foam is used in insulation. See also Insulation (Thermal) More than half (60%) of the rigid foam consumed in 1994 was in the form of board or laminate die remainder was used in pour-in-place and spray foam applications. 

More than 50% of the rigid polyurethane foams manufactured in the United States in 1994 are used in the construction industry (Table 10). About 60% of the total rigid foam is used in laminated boards and insulation panels about 30% is poured in place. Insulated appliances is another important use of rigid insulation foam. 

The frothing process was developed by the Du Pont Co. (25). The process has the following advantages isotropic physical properties and lower foaming pressure. The method is preferably used for large-panel production at in-plant production or pour-in-place foaming in field applications, e.g., building panels, chemical tanks, etc. 

Flexible urethane foams include slabstock foam, molded foam, and pour-in-place foam. In some cases, the latter two foams can be called flexible RIM foams (RIM is an abbreviation for reaction injection molding). 

In addition, this system has been modified by adding dibenzyl sorbitol to give high thixotropicity to the system to prevent penetration of the system into foam cells. For these reasons the foam system is very suitable for pour-in-place application into small foam voids, e.g., 1 to 10 cm, for repairing surface air voids of molded automotive-foam seats to reduce the rejection rate, thereby resulting in lowering production costs. 

TDI Prepolymer Process. This process has the major advantage of better flowability in pour-in-place processes, e.g., household-refrigerator insulation, than crude TDI-based or polymeric MDl-based processes. An example of TDI-based prepolymers and a formulation for making rigid urethane foam on a small scale is shown below. 

Foam-In-PIace. The foam-in-place (or pour-in-place) method is used for the production of refrigerators, deep freezers, sandwich panels, and similar applications. This process is also used for field applications, such as indoor- and outdoor-tank insulation (79), LPG (liquefied petroleum gas) tank insulation, heavy oil-tank insulation, chemical-tank-car insulation, and pipe-covering insulation, among others (79). 

The commercialization of simUar foams was followed by Hexaform (trade name ICl) in 1968 (57). The commercialization was later followed by Upjohn Company (trade name Kode 25) and Jim Walter Corp. (trade name Thermax). Foaming methods of modified-isocyanurate foams include slabstock, laminate, block, pour-in-place and spraying. 

The pour-in-place process is applied to chemical-plant insulation and building insulation. These insulations can be made by pouring the system into the void space formed by surface materials and their reinforcing board in the presence of spacers. A number of pipes and reaction towers of petrochemical plants in Japan have been insulated by the pour-in-place process (79). 

The frothing process is widely used in rigid urethane foam pour-in-place applications. The frothing process of urethane-modified isocyanurate foams has been used for the insulation of petrochemical plants, e.g., spherical tanks, reaction towers, etc. (79). An example of the frothing system is shown below (71). 

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