Coupled effects of glass fiber and time on fluidity and stability of self-compacting composites

Author(s): I. Mehdipour, K. Amini, M. Khanjani
Paper category: Conference
Book title: 8th RILEM International Symposium on Fiber Reinforced Concrete: challenges and opportunities (BEFIB 2012)
Editor(s): Joaquim A.O. Barros
Print ISBN: 978-2-35158-132-2
e-ISBN: 978-2-35158-133-9
Publisher: RILEM Publications SARL
Pages: 55 - 65
Total Pages: 10
Language: English

Abstract: 
Repair of concrete infrastructures can often necessitate the use of self-compacting composites given the complexity of the cast elements, high degree of restriction by the reinforcement and cover over the reinforcement, and difficult access to ensure proper consolidation. On the other hand, in case of consistency, the time-dependent rheological behavior of self-compacting composites incorporating various chemical admixtures for prolonged concreting applications is more critical compared to that of ordinary cement based composites. The compatibility of cement matrix and fiber properties is one of the key parameters in the successful design of fiber reinforced cementitious composites. Glass fiber (GF) reinforcement can be an excellent solution to somewhat cover the compatibility of whole composite. Use of GF depending on fiber content may considerably increase the consistency retention of mixture during a given period of time and also significantly improve the toughness, energy absorption capacity, reduce cracking and durability of self-compacting composites. The main objective of this paper is to investigate the combined effects of glass fiber and time on the performance of glass fiber reinforced self-compacting composites (GFRSCC) mixtures used to enhance the consistency retention of GFRSCC mixtures at prolonged time. Four self compacting composite were prepared containing 0, 0.1, 0.3, and 0.5 percent of 6 mm long glass fibre (with aspect ratio of 150). The fresh properties of fresh GFRSCCs are investigated by mini-slump flow diameter and mini V-funnel flow time test to estimate the yield stress and viscosity of the composites, respectively. To study the effect of time, the mixtures were subjected to prolonged mixing for up to 50 min and flow measurements were taken at 5 min and then at each 5 min interval.
The results show that using an appropriate amount of glass fibers improves the stability of fresh mixtures. On the other hand, there seems to be a fiber “optimum volume fraction”, beyond which its influences on the stability of mixtures reverse trend. Fibers in this time tending to become entangled together and formed clusters at the center of the flow spread and bleeding due to the balling form.

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00