The effects of Visual Stability Index (VSI) on fresh segregation of self consolidating concrete (SCC) using fly ash class C and F

摘要

Self-consolidating concrete (SCC) is a concrete technology that is growing in popularity with the precast/prestressed industry and contractors. SCC increases the ease of concrete placement as well as reduces overall cost by requiring less labor and time for a concrete placement. This study is part of the proposed project by Tennessee Department of Transportation (TDOT) carried out by University of Tennessee at Chattanooga (UTC) to develop four new SCC mixtures (two Class P-SCC (precast) and two Class A-SCC (general use), and insure they meet the minimum strength and durability requirement for TDOT Class P and Class A mixtures. The objectives of the study presented in this thesis are to analyze a survey of state Departments of Transportation SCC specifications and requirements and investigate the effect of fly ash class and aggregate size and shape on fresh properties of Class A-SCC. In addition, investigate the relationship between Visual stability index (VSI) and fresh segregation of SCC. Finally, recommend the specifications of fresh performance requirements for the Class A-SCC that the Tennessee Department of Transportation (TDOT) should apply to establish SCC stability and flowability during the production of general concrete elements.