e. Epoxy Grouts. Epoxy resins, when mixed with sand, form a chemical 

 grout which has excellent chemical and physical properties. These grouts 

 may be used to patch cement construction such as roadways, or to patch 

 certain worn or corroded metal parts. These epoxy grouts have superior 

 adhesion properties with high strength and corrosion resistance. Many other 

 grout types are available, e.g., silicates, acrylics, and lignin. 



4. Environmental Considerations . 



a. General. The environment interacts and combines with the magnitude 

 and duration of stress, strain, and temperature to further alter material 

 response and strength of plastics. Chemical environments, {for example, 

 ultraviolet (UV) exposure, contact with petroleum products and sustained 

 elevated temperature}, can have profound influence on performance and hence 

 must be a consideration in the design and use of plastics. However, many 

 synthetics have a high chemical stability and resistance to chemical attack 

 by acids and alkalies. The failure to design for environmental effects as 

 they interact with sustained stress or strain has been the chief cause of 

 failure of plastic products. 



Fillers and plasticizers alter the basic response and strength of 

 plastic materials. Fillers (e.g., clay, limestone, carbon black, and other 

 inert materials), introduced to increase stiffness, improve processing 

 characteristics, or lower costs, may also be used to improve UV resistance 

 or heat resistance. Plasticizers change the physical properties of plastics 

 such as impact resistance, flexibility and toughness and abrasion resistance. 

 The introduction of strong fibers, such as glass, will improve strength, 

 stiffness, and dimensional stability. 



Stabilizers are an important group of additive materials, used to increase 

 the resistance of plastics to the deteriorating influence of weather, UV 

 light, or radiation. Stabilizers are also used to retard degradation by 

 heat. Flame-retardant chemicals, such as phosphorous and halogens, can be 

 incorporated in the molecular structure to improve fire resistance. 



Plastics in common use in the coastal environment, such as the epoxies, 

 polyesters, polyethylene, polypropylene and polyvinyl chloride, are generally 

 not considered to be biodegradable. However, these plastics in virtually all 

 structural forms (such as tanks, pipes, bouys or geotextile fabrics) have a 

 high corrosion deterioration in the coastal environment and when exposed to 

 chemicals, except for some of the aliphatic solvents, such as keytones. 



b. Geotechnical Fabrics . Atmospheric temperature, chemicals (in 

 concentrations normally found in soils), and wetting and drying are factors 

 having little or no effect on geotextiles conforming to the chemical and 

 physical requirements stated in the text and Table 39. Trees may grow 

 through the fabric. In the few cases where this has been observed, there 

 was no detrimental effect to the function of the filter because the geo- 

 textile was sealed tightly against the tree trunk at the point of penetra- 

 tion. 



No standard test method has been developed to determine the biological 

 resistance of geotextiles. However, all investigators have concluded that 

 fabrics composed of the synthetic polymers described earlier, are inert to 



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