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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2026, Vol. 45 ›› Issue (4): 1220-1230.DOI: 10.16552/j.cnki.issn1001-1625.2025.1029

• Cement and Concrete • Previous Articles     Next Articles

Performance Optimization and Application of Geopolymer Grouting Repairing Material for Concrete Crack

WEI Shupeng1(), CUI Chenchen1, WANG Dehui2, LUO Zhengdong3,4(), LUO Jin5, WANG Yajun1, CHEN Yinghao3,4   

  1. 1.Xinjiang Road and Bridge Construction Group Co. ,Ltd. ,Urumqi 830000,China
    2.College of Civil Engineering,Fuzhou University,Fuzhou 350108,China
    3.College of Civil Engineering,Xiangtan University,Xiangtan 411105,China
    4.Hunan Provincial Key Laboratory of Geomechanics and Engineering Safety,Xiangtan 411105,China
    5.Xinjiang Luqiao Bridge Construction Co. ,Ltd. ,Urumqi 830019,China
  • Received:2025-10-22 Revised:2025-12-03 Online:2026-04-20 Published:2026-05-14
  • Contact: LUO Zhengdong

Abstract:

This study experimentally investigated the feasibility of using geopolymer grouting repairing material (GGRM) for concrete crack, with the aim of overcoming limitations of conventional methods such as slow setting and inadequate erosion resistance. Firstly, based on practical and applicability considerations, GGRM was modified using three types of expansive agents: magnesium oxide, calcium oxide, and calcium sulfoaluminate. The evolution of workability and mechanical properties of the grout was the primary focus. Subsequently, the optimal GGRM was selected to repair concrete cracks of varying widths. The compressive strength and resistance to sulfate and chloride salt erosion of the repaired matrix were evaluated. Finally, microscopic characterization techniques were employed to elucidate the modification mechanism of expansive agents and the bonding behavior at the crack interface. The results show that expansive agents effectively compensate for the shrinkage deformation of GGRM. Fluidity is highly sensitive to variations in calcium sulfoaluminate content, and increasing calcium oxide content significantly shortens the setting time of the grout. However, all three expansive agents have a negative impact on the compressive strength of GGRM. The compressive strength of the cracked C30 concrete matrix repaired using magnesium oxide-modified GGRM reaches up to 28.8 MPa. After 28 d of erosion in a 5% (mass fraction) NaCl solution, the strength retention rate of the repaired matrix is between 95.4% and 97.7%. Moreover, after exposure to 5% (mass fraction) Na2SO4 solution for 28 d, the strength retention rate of the concrete matrix is significantly higher than that of the cement-repaired control group. The key mechanism for mitigating shrinkage deformation is the formation of slightly expansive crystals such as Mg(OH)2, Ca(OH)2, and ettringite (AFt). The enhanced bonding strength at the GGRM existing concrete interface is attributed to bridging connections by geopolymer gels and frictional interlocking effects.

Key words: geopolymer, expansive agent, workability, compressive strength, crack repair, microscopic mechanism

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