In situ reaction-strengthening of ice-templated porous geopolymers for high anisotropy and robustness

TY - JOUR

T1 - In situ reaction-strengthening of ice-templated porous geopolymers for high anisotropy and robustness

AU - Li, Fangxian

AU - Zhang, Chaofeng

AU - Yu, Qiang

AU - Zheng, Li

AU - Wei, Jiangxiong

AU - Yu, Qijun

N1 - Publisher Copyright: © 2025

PY - 2025/12/11

Y1 - 2025/12/11

N2 - Ice-templating enables ordered porous architectures but fails in geopolymers due to suppressed reactions at cryogenic temperatures and water loss during sublimation, yielding fragile scaffolds. We propose an in situ reaction strategy that converts ice from a passive porogen into a controlled-release solvent. By introducing a staged low-temperature polymerization (−5 °C to +5 °C) before sublimation, the gradually melting ice initiates geopolymerization in situ, forming a C-(A)-S-H gel that strengthens pore walls. This approach prevents collapse, ensures faithful ice-template replication, and yields porous geopolymers with compressive strength above 6.5 MPa, far exceeding conventional counterparts (<2 MPa). The materials exhibit pronounced anisotropy (σz/σy > 3.6) and well-defined lamellar pores. This strategy addresses a key limitation in ice-templating and opens pathways for fabricating high-performance porous materials from water-dependent reactive systems.

AB - Ice-templating enables ordered porous architectures but fails in geopolymers due to suppressed reactions at cryogenic temperatures and water loss during sublimation, yielding fragile scaffolds. We propose an in situ reaction strategy that converts ice from a passive porogen into a controlled-release solvent. By introducing a staged low-temperature polymerization (−5 °C to +5 °C) before sublimation, the gradually melting ice initiates geopolymerization in situ, forming a C-(A)-S-H gel that strengthens pore walls. This approach prevents collapse, ensures faithful ice-template replication, and yields porous geopolymers with compressive strength above 6.5 MPa, far exceeding conventional counterparts (<2 MPa). The materials exhibit pronounced anisotropy (σz/σy > 3.6) and well-defined lamellar pores. This strategy addresses a key limitation in ice-templating and opens pathways for fabricating high-performance porous materials from water-dependent reactive systems.

KW - Porous geopolymer

KW - Ice-templating

KW - In situ reaction

KW - Anisotropy

KW - Mechanical properties

UR - https://www.scopus.com/pages/publications/105024361843

U2 - 10.1016/j.cemconres.2025.108104

DO - 10.1016/j.cemconres.2025.108104

M3 - Article

SN - 0008-8846

VL - 201

JO - Cement and Concrete Research

JF - Cement and Concrete Research

M1 - 108104

ER -