Keywords and Phrases
Bond Strength; Compressive Strength; Dynamic Segregation; Rheology; Self-Consolidating Concrete; Ultrasonic Pulse Velocity
"Self-Consolidating Concrete (SCC) is more vulnerable to stability problems as a consequence of its high flowing ability compared to conventional vibrated concrete. Dynamic segregation refers to the tendency of the concrete constituents to separate from the suspended matrix, usually in horizontal direction while being cast into the formwork or due to an impact. Similarly to static segregation, dynamic segregation can affect the homogeneity of SCC. Therefore, it is highly essential to ensure a proper dynamic stability in order to enhance the uniformity of in-situ properties of pre-stressed beams.
In this research project, the effects of SCC mix design parameters are investigated using the T-box test as a method to assess dynamic segregation. Changes in chemical admixture type and content, paste volume, sand-to-total aggregate ratio (S/A), w/cm and the width of the T-box have been evaluated. The results show that dynamic segregation of SCC is dependent on the rheological properties of the concrete, paste volume and S/A.
In a second part, the influence of dynamic segregation on the uniformity of precast, pre-stressed beams is investigated. Six 9 m and three 18 m long beams were produced with SCC. To determine the uniformity of the mixture, a comparative survey across the beam height and along its length was performed. Also, the bond strength of pre-stress strands with SCC was investigated. Results from the UPV and compressive strength demonstrate a variation in the uniformity of the concrete, mainly at the casting point. For the bond strength, with increasing dynamic segregation, the bond between the strand and the concrete at the top 1/3rd of the beam height, relative to the bond in the middle 1/3rd, decreases"--Abstract, page iii.
Civil, Architectural and Environmental Engineering
M.S. in Civil Engineering
Missouri University of Science and Technology
xv, 120 pages
© 2016 Aida M Ley Hernandez, All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Self-consolidating concrete -- Mechanical properties
Self-consolidating concrete -- Additives
Precast concrete -- Testing
Concrete beams -- Testing
Electronic OCLC #
Ley Hernandez, Aida Margarita, "Influence of mix design parameters on dynamic segregation of self-consolidating concrete and consequences on performance of precast beams" (2016). Masters Theses. 7557.