Recent Experience With Armor Stone Cracking in the Buffalo District

Marcus, David W.; ,

Recent Experience With Armor Stone Cracking in the Buffalo District

by David W. Marcus, USACE, Buffalo, United States,

Document Type: Proceeding Paper

Part of: Durability of Stone for Rubble Mound Breakwaters

Abstract:

Accelerated deterioration of large armor stone on the Cleveland East Breakwater, Cleveland, Ohio has resulted in the need for more intensive monitoring of the entire armor stone production and selection process. Several important findings and developments that resulted from the Cleveland East Breakwater and other damaged stone investigations by the U.S. Army Engineer District, Buffalo (CENCB) include: (1) the main cause of the most significant and undesirable fracture patterns in the armor stone appear to be a direct result of blasting, (2) the presence of extensive stone damage at the older projects examined suggests that damaged stone has continued to deteriorate with exposure, (3) detailed visual inspections by trained inspectors, skilled in the identification of significant blast induced fractures and working in open areas where the stone can be walked around and rolled over if necessary, has proven to be a good method for assuring the delivery of sound and durable stone. Presently, CENCB is implementing several changes to the stone selection/approval process and is recommending several others based upon these findings. A case study of the recent 1988-1989 stone rehabilitation project on the Cleveland East Breakwater will be reviewed in detail. Some findings from other field investigations will also be discussed along with recommendations for changes in the stone evaluation process.

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