SELECTION OF DURABLE CLOSURE POUR MATERIALS FOR ACCELERATED BRIDGE CONSTRUCTION

摘要

With the public's demands for reduced construction time and traveling delays,full-depth precast bridge decks or decked bulb tees (DBTs) are being more widely used.When these systems are used,precast elements are brought to the construction site ready to be set in place and quickly joined together.Then,a concrete closure pour completes the connection.The selection of closure pour materials is critical.The procedure and methods for selecting durable closure pour (CP) materials are discussed in this paper.The accelerated construction is quantified as two categories:overnight cure of CP materials and 7-day cure of CP materials.For both categories,candidate materials are selected first based on literature review of published data as well as tests of compressive strength and flow and workability.Then,the performance criteria for selecting durable CP materials for both categories is developed based on durability tests of selected candidate materials.These durability tests include freezing-and-thawing durability,shrinkage,bond,and permeability tests.