| Utility industries use wooden poles for installation of cables, lights, telephone, and transmission lines. It is estimated that over 250,000 poles are utilized annually varying in height from 30 feet to 40 feet in the Midwest alone. In addition, over 1,000,000 smaller size utility poles (15--30 ft) are utilized. This project involves studies to develop and demonstrate CCB-based composite poles to replace wooden poles. The performance of wooden poles (designed using ANSI standards) was used as the benchmark to design the composite poles.; A polymer filled with CCBs forms the foundation material for the composite pole. The developed composite cylindrical pole consists of a very stiff outer-shell containing 5 to 30% CCBs with or without an inner-core material containing 40 to 60% CCBs. Several composite pole designs were developed. Research was conducted to characterize the developed materials and to investigate the effect of fly ash loading percentage, particle size, post-curing temperature, and post-curing time on engineering properties of the developed materials. To further enhance the stiffness and strength of the CCBs-filled composite materials, fiberglass was added as reinforcement in the outer-shell. Model poles, approximately 5-in in diameter and 0.25 in. wall thickness and several flat panels (12 in. x 20 ft x 0.25 in.) were fabricated in Pennsylvania using the developed materials and a pultrusion fabrication process. Engineering properties of the manufactured poles were characterized through flexural bending test, off-axis tensile and compression tests, burnout test, fiber volume fraction (FVF) analysis, micro/macro-mechanics analysis, finite element analysis, and full-size cantilever bending test. Depending on the elastic modulus of the wooden pole (600,000 to 1,200,000 psi), a cylindrical engineered pole with an outer-shell thickness of 0.25 to 0.5 in. and an outer diameter of 9.5 to 12.5 in. will be comparable to a class-4 wooden pole. Such a pole will weigh 65 to 80% of the corresponding wooden pole. Laboratory testing and field demonstrations of the model poles reveal that CCBs-based composite utility poles have commercial potential to replace wooden poles. |
