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原文传递 Evaluation of Mechanized Consolidation of Bridge Deck Concrete in Illinois; Final rept. 1995-98

题名：	Evaluation of Mechanized Consolidation of Bridge Deck Concrete in Illinois; Final rept. 1995-98
作者：	South, J. M.
关键词：	Bridge decks; Concrete construction; Vibratory compacting; Consolidation; Vibrators(Machinery); Performance evaluation; Illinoise; Drill core analysis
摘要：	Mechanized methods of vibratory concrete consolidation were used on all or part of fourteen bridge decks in Illinois from 1996 to 1998. The method used on twelve decks consisted of vertical insertion of vibrators in a grid pattern. A transverse drag-through process was used on two decks. Cores were analyzed from decks of both types and compared with cores from conventionally poured decks in order to measure differences in entrapped air voids and in-place density. Based on statistical analysis, the grid pattern method was found to be a significantly better than both the drag-through and conventional methods for reducing entrapments per square inch and increasing in-place density. The drag-through method was found to be better than the conventional method for reducing entrapments, but no difference was found for density. Segregation was found in the drag-through cores, but not for either the grid pattern or the conventional method. Some problems were noted on construction sites, mainly having to do with increased weight of the finishing machine and the effect of greater vibration intensity on superplasticized concrete. Costs associated with use of the grid pattern method were approximately $5.50 per square yard of bridge deck. A revised specification and guidelines for use are presented.
总页数：	50p
报告类型：	科技报告