WANG G, CAI J. Experimental study on nano-material modified Portland cement-based grouting material [J]. Journal of Henan Polytechnic University (Natural Science), doi:10.16186/j.cnki.1673-9787.2024030080.

doi:10.16186/j.cnki.1673-9787.2024030080

Received：2024-03-29

Revised：2024-05-06

Online：2024-10-31

Experimental study on nano-material modified Portland cement-based grouting 

material

WANG Gang^1,2, CAI Jin^1,2

1.Shandong Provincial Key Laboratory of Civil Engineering, Disaster Prevention and Mitigation, Shandong University of Science and Technology, Qingdao 266590, Shandong, China; 2.College of Civil Engineering, Shandong University of Science and Technology, Qingdao 266590, Shandong, China

Abstract: Objectives For the engineering problem of rock mass microfracture grouting towards reinforcement and seepage prevention, Methods a Portland cement-based grouting material modified by nano-material was developed through Taguchi-grey correlation optimization analysis method and orthogonal test. Based on the signal-to-noise analysis of Taguchi method, the influence law of dosage of nano-CaCO₃, polycarboxylate superplasticizer, ultrafine fly ash and water-cement ratio to the properties of grouting material such as viscosity, water release rate, setting time and stone body strength was analyzed systematically. Results According to the orthogonal test results, the grouting material under the optimal ratio obtained from Taguchi-grey correlation optimization analysis had considerable fluidity and mechanical properties, which ensured the injectability and reinforcement effect. According to the signal-to-noise ratio analysis of influence law, nano-CaCO₃ had a significant influence on the fluidity of grouting materials. The viscosity increased, water release rate gradually decreased, and the 28 d stone body strength increased firstly and then decreased with the increasing nano-CaCO₃ content. Polycarboxylate superplasticizer could decrease the viscosity of grouting material, but it would lead to the extended setting time and increased water release rate, and it had a comparatively low influence on the 28 d stone body strength. Ultrafine fly ash could also decrease the viscosity of grouting material, however, it was detrimental to shorten the setting time and to improve the 28 d stone body strength. The water-cement ratio had the most significant effect on water release rate, setting time and 28 d stone body strength. The fluidity of grouting material could be improved with increasing water-cement ratio, however, it would result in the prolongation of setting time and decreased 28 d stone body strength. Conclusions The nano-material modified cementitious grouting material developed had considerable fluidity, stability and mechanical properties, the results of the study provided theoretical and experimental support for the material selection of practical grouting engineering.

Key words: grouting material; orthogonal test; Taguchi method; nano-CaCO₃; microfracture