Reduction of shrinkage by Superabsorbent polymers (SAP) in fibre reinforced mortars

• Published in: Construction & building materials 2021-06, Vol.288, p.123109, Article 123109
• Main Authors: Rostami, Rohollah, Klemm, Agnieszka J., Almeida, Fernando C.R.
• Format: Article
• Language: English
• Subjects: Autogenous shrinkage; Drying shrinkage; Plastic shrinkage; Polymeric fibres (PF); Superabsorbent polymers (SAPs)
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.123109

•Efficiency of SAP in shrinkage reduction of fiber reinforced mortars is analysed.•Reduction of plastic and autogenous shrinkages strongly depends on particle sizes.•Finer SAP reduces plastic and autogenous shrinkage by up to 75% and 124% respectively.•Reduction of drying shrinkage depends on water absorption capacity. Fibre reinforced mortars (FRM) containing fly ash (FA) and ground granulated blast-furnace slag (GGBS) may suffer from volumetric changes and despite fibre reinforcement, internal curing may be required. This paper evaluates the efficiency of Superabsorbent Polymers (SAP) in reduction of shrinkage. Autogenous (AS), plastic (PS) and drying (DS) shrinkage were analysed for FRM with three types of cement (CEM I, CEM II/B-V and CEM III/A) and three types of SAPs (different water absorption capacities and different particles sizes). The experimental results showed that SAP substantially contribute to the total shrinkage reduction in cementitious mortars and reduce susceptibility to crack formation. Reduction of plastic and autogenous shrinkage is highly dependent on particle sizes. Finer SAPs lead to better performances with reductions reaching 75% for PS and 124% for AS. Reduction of drying shrinkage, although substantially lower (up to 12%), can be achieved by application of SAPs with lower water absorption capacities. The effect of particle sizes is less important for drying shrinkage.