Superabsorbent polymers to seal and heal cracks in cementitious materials

Didier Snoeck

doi:10.21809/rilemtechlett.2018.64

Abstract

Superabsorbent polymers (SAPs) are promising admixtures to improve properties in cementitious materials. Not only useful to mitigate autogenous shrinkage and to increase the freeze-thaw resistance, SAP particles may enhance self-sealing and self-healing in cementitious materials. The self-sealing leads to a regain in water tightness and promoted autogenous healing may prove to be useful to limit repair works caused by concrete cracking. By providing sufficient building blocks for healing, limiting the crack width by means of synthetic microfibers and inducing water by means of SAPs, a smart cementitious material is obtained. This material can be an excellent material to use in future building applications such as tunnel works and ground-retaining structures. This paper gives an overview of the current status of the research on SAPs in cementitious materials to obtain sealing and healing.

Highlights

Concrete is prone to cracking and the cracks interconnect flow paths for water, possibly containing harmful substances
Superabsorbent polymers (SAPs) can be used in cementitious materials for reducing the autogenous shrinkage [7,8,9,10,11,12], for changing the rheology of the fresh material [13], and for increasing the freeze/thaw resistance [14], amongst others
The mitigation of autogenous shrinkage was investigated on samples with and without additional supplementary cementitious materials such as fly ash and blast‐furnace slag [10]

Summary

Introduction

Concrete is prone to cracking and the cracks interconnect flow paths for water, possibly containing harmful substances. Due to their swelling capacity upon contact with fluids, SAPs may cause a decrease in permeability of cracked cementitious materials. It was found that due to the swelling effect of the SAPs, the reduced water movement speed, which is critical to obtain autogenous healing, is optimal as cracks are able to close due to deposited crystals.

Results

Conclusion