Multi-Factor Orthogonal Test Analysis of Mechanical Properties and Fluidity of Steel Fiber Sprayed Mortar

Abstract

Abstract: In order to explore the influence of matrix factors on the mechanical properties and fluidity of steel fiber sprayed mortar, the mechanical properties and fluidity of mortar specimens were tested based on orthogonal test method. The results show that the ratio of sand to cement (A) has a great influence on the splitting tensile strength, and has a certain influence on 7 d compressive strength, and has a particularly significant effect on later flexural strength. The influence of steel fiber content (B) on splitting tensile strength, early flexural strength and early and middle compressive strength is particularly significant, significant and insignificant, respectively. The content of accelerator (C) has a significant effect on compressive strength before 7 d and the splitting tensile strength in middle and late stages. The content of fly ash (D) has significant influence on compressive strength in late stage. The four factors have no significant influence on fluidity. The optimal mix ratio of compressive strength, flexural strength, splitting tensile strength and fluidity are obtained by analytic hierarchy process as A₁B₃C₃D₁, A₃B₃C₁D₂, A₃B₃C₃D₁, A₂B₁C₁D₃, and the optimal mix ratio is obtained by efficiency coefficient method as A₂B₃C₁D₂. The steel fiber plays a bridging and anchoring strengthening role in matrix. During the hydration process, the accelerator consumes a large amount of Ca(OH)₂ and generates ettringite, which is the main reason for the rapid increase in early strength of sprayed mortar.

Key words: sprayed mortar, steel fiber, orthogonal test, efficiency coefficient method, microanalysis

CLC Number:

TU528.58

PAN Huimin, ZHANG Hao, LI Mengyi, XIE Shaokang, ZHAO Qingxin. Multi-Factor Orthogonal Test Analysis of Mechanical Properties and Fluidity of Steel Fiber Sprayed Mortar[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(2): 466-477.

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