MITIGATION OF EARLY AGE SHRINKAGE OF UHPFRC BY USING SPENT EQUILIBRIUM CATALYST

Author(s): Ana Mafalda Matos, Sandra Nunes, Carla Costa
Paper category: Proceedings
Book title: proceedings of the International RILEM Conference on Materials, Systems and Structures in Civil Engineering Conference segment on Service Life of Cement-Based Materials and Structures
Editor(s): Miguel Azenha, Ivan Gabrijel, Dirk Schlicke, Terje Kanstad and Ole Mejlhede Jensen
ISBN:978-2-35158-170-4
e-ISBN: 978-2-35158-173-5
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 412-421
Total Pages: 10
Language : English

Abstract: Strengthening of structural concrete elements with ultra-high performance fibre reinforced
composites (UHPFRC) layers is being successfully performed in recent years. The main
advantage of UHPFRC in this context is that it can play a double function (water tightness
and strengthening), while enabling short-time interventions.
UHPFRC material exhibits remarkable mechanical properties namely, strain hardening in
tension and extremely low water permeability. However, due to the very low water/binder
ratio it is prone to autogenous shrinkage. The restraint provided by the substrate to the free
shrinkage of the new layer generates built-in stresses which can impair its performance. As
such, seeking strategies to reduce the autogenous shrinkage is an objective to pursue.
The spent equilibrium catalyst (ECat) is a waste generated by the oil refinery industry with
very high pozzolanic activity and high specific surface (150 m2/g) which promotes a
significant water absorption (about 30%, by mass), thus has a great potential to work as an
internal curing agent in UHPFRC. Within this scope, this paper describes research on the
viability of using ECat to mitigate autogenous shrinkage of UHPFRC. Test results showed a
significant reduction of autogenous shrinkage in UHPFRC mortars without fibres and 20%
and 30% of sand replacement by ECat.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00