Shrinkage of high-performance fiber-reinforced concrete with adapted rheology

Abstract

The results of shrinkage (εsh) of fiber-reinforced self-consolidating mortar (FR-SCM), fiber-reinforced superworkable concrete (FR-SWC), and fiber-reinforced self-consolidating concrete (FR-SCC) are compared to results determined from different models. In total, four FR-SCM, five FR-SWC, and 10 FR-SCC, mixtures representing a wide range of mixture proportioning were studied. Five types of fibers, including steel, synthetic, and hybrid fibers having various properties were employed. The fiber volume varied from 0.25% to 0.75% for the FR-SCC mixtures and from 1.4% and 1.6% in the case of FR-SCM mixtures. The εsh results were evaluated for 13 months. Test results indicated that the εsh of FR-SWC/FR-SCC was lower than that of SCC. The drying shrinkage (εdr), which is part of the total shrinkage, εsh, was found to be mainly affected by the total porosity and volume of pores smaller than 50 nm. The εsh results were compared to values predicted from different models, including the AASHTO LFRD (2017), ACI 209 (2008), Bažant B4 (2015), B4s (2015), CEB-FIP (2010), Eurocode 2 (2004), Gardner and Lockman (2000), and JSCE (2007) models that were developed for conventional, non-fibrous concrete. The Aslani and Maia (2013), Khayat and Long (2010), and Poppe and De Schutter (2005) models proposed for self-consolidating concrete and FR-SCC were also considered. The εsh models of the fibrous mixtures were modified to better fit the experimental results. The modified εsh models were shown to yield accurate prediction of εsh of FR-SCM and FR-SWC/FR-SCC. The modified JSCE model provided the best overall prediction for εsh for the FR-SCM and FR-SWC/FR-SCC mixtures.