Federal Highway Administration
400 Seventh St., S.W.
Washington, D.C. 20590
March 8, 2007
In Reply Refer To: HSSD/B-155
Mr. Ing. M.E. Hernando Salas J.
Gerente Division Armco
Carrera 68 # 23 - 52
Dear Mr. Salas :
In your November 15, 2006, letter to Mr. Nicholas Artimovich of my staff, you sent him a copy of a test report prepared by the Texas Transportation Institute, dated November 10, 2006, and entitled "Pendulum Testing of the Corpacero Spacer Block" and a CD showing the tests that were conducted with your product. You requested acceptance of your product for use with strong steel-post W-beam guardrail on the National Highway System (NHS).
The Corpacero HDPE spacer blocks were 350 mm (13.8 inches) tall, 187 mm (7.4 inches) deep, and 100 mm (3.9 inches) wide. The chemical composition of the spacer blocks was 55.0 percent recycled HDPE, 43.5 percent recycled rubber, 1.0 percent Black Master Batch, and 0.5 percent anti-oxidizing agent, produced by Mater Andina S.A. ref. M010051093. The spacer block used in the first pendulum test weighed 3.7kg (8.2 pounds) and the block used in the second pendulum test weighed 3.5 kg (7.8 pounds). The Corpacero HDPE spacer blocks were mounted on W6 x 9 steel posts, which were mounted on a steel reaction plate. A W-beam backup plate was mounted on the front of the spacer block to simulate a W-beam guardrail. A drawing of the Corpacero HDPE spacer block is enclosed for reference.
In both tests the posts rotated approximately130 degrees and the W-beam backup plate separated from the spacer block. The blocks themselves remained on the post in one piece with only a slight tear on the right side lip and the face was indented.
Based on the results of the pendulum tests using the Corpacero offset block, your product may be considered acceptable for use when requested by a highway agency on the NHS with a strong-post W-beam guardrail when it conforms to the dimensions noted above and the enclosed drawings, is composed of the same materials as the tested blocks, and is installed flush with the top of the post. As with all other alternative material offset blocks accepted for use on the NHS, this acceptance is based solely on the reported impact performance of the Corpacero block and is not intended to address the long-term performance or durability of the product. Field installations should be carefully monitored to verify expected performance and service life.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
John R. Baxter, P.E.
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