摘要 |
A filled structure includes a fiber reinforced resinous hollow structure having a tensile strength of at least 30,000 psi, an inside surface forming a boundary which encloses a space, and a hard core within the space. The hard core has a density of at least 35 pounds per cubic foot and a compressive strength of at least 1500 psi. The hard core is formed from a mixture of particulate cementitious material and liquid such that when the mixture hardens, the hard core is mechanically locked to the inside surface of the hollow structure.
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