Durability performance of superabsorbent polymer incorporated concrete modified by nano-silica addition in seasonal frozen regions

Xiaoqian Dai, Aiqin Shen, Zhennan Li, Jingyu Yang

Research output: Contribution to journalArticlepeer-review

Abstract

In seasonal frozen regions, ion erosion and freeze-thaw (F-T) cycles threaten pavement concrete durability. This study evaluates the suitability of superabsorbent polymer (SAP) concrete modified by nano silica (NS) for enhancing durability. Tests were conducted to analyze chloride impermeability and frost resistance effects on modified SAP concrete. The coupling impact of ion erosion and freeze-thawing was also evaluated. Mercury intrusion porosimetry (MIP), scanning electron microscopy, and energy dispersive spectrometry were employed to investigate microstructure characteristics. Results demonstrated that NS-modified SAP concrete exhibited high resistance to ion erosion and F-T cycles. Adding 3 % NS reduced the relative dynamic elastic modulus (RDEM) loss by 23.21 % after 300 F-T cycles. The enhancement was more pronounced under the coupled action of ion erosion and freeze-thawing, and the RDEM loss and scaling quantity per unit area of NS-3 % decreased by 13.21 % and 41.48 % respectively, and compressive strength was 28.33 % higher than that of SAP concrete after 135 salt-frost cycles. MIP testing indicated that 3 % NS significantly improved pore structure, reducing deterioration in much harmful pores by 12.82 %. SAP promoted the efficient pozzolanic reaction of NS, generating high-density C-S-H. Additionally, second-hydration products were adsorbed by the ionization of SAP microgel, densifying its shrinkage voids and delaying ITZ width and micro-crack propagation, thereby enhancing concrete durability.
Original languageEnglish
Article number109727
Number of pages16
JournalMaterials Today Communications
Volume40
DOIs
Publication statusPublished - Aug 2024

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