Standardization of Fatigue Characteristics of Cement-Treated Aggregate Base Materials under Different Stress States

Abstract

In this study, to decrease the evaluation uncertainty of the fatigue characteristics of cement-treated aggregate base materials under different test conditions, unconfined compressive, indirect tensile, flexural tensile strength tests and fatigue tests of these base materials with different cement content and at different curing times were carried out. The Weibull distribution was employed to analyze fatigue test results. The standardization model of fatigue characteristics for cement-treated aggregate base materials under different stress states was established. Based on the interval analysis theory, the fatigue characteristic model under different stress states was established using interval parameters. Results revealed that the curing time and cement content considerably affect the strength and fatigue characteristics of cement-treated aggregate base materials, and with increasing cement content and curing time, the fatigue resistance of cement-treated aggregate base materials can be improved. Clear differences between the fitting parameters a and b of the S-N fatigue equation of cement-treated aggregate base materials under different stress states were observed, which can be eliminated by using the analysis method based on the Weibull distribution and the standardization model, and a unified expression for the cement-treated aggregate base materials under different test conditions was realized. A Standardization model of fatigue characteristics based on the interval analysis new method could solve several problems such as inadequate sampling representation, low precision, and insufficient stability of test equipment; thus, the errors caused by materials, structures, the environment, and loads can be reduced, making the fatigue life interval more reasonable and scientific compared to the point numerical fatigue life. Regression parameters a and be were in intervals [9.0, 10.6] and [9.9, 11.3], respectively, and parameters a and b were similar, which improve the test accuracy and reduce the data error.

Load spreading in ultra-thin high-strength steel-fibre-reinforced concrete pavements

“…The stress level ranged from a minimum of 0.24 for C1 materials to a maximum of 1.22 for C4 materials, with the number of cycles that can be endured decreasing as the strength decreased. The fatigue life of cemented materials loaded to a stress level under 0.50 is generally good, being able to absorb millions of load cycles (Xie et al 2018). For the three-layer pavement system modelled using 3D LE FE, the stress levels calculated for the base layer underneath a 50 mm HS-SFRC layer indicated that C1 and C2 materials would perform well under 80 kN axle loads.…”

“…The flexural strength is determined as a fraction of the UCS. Although the fatigue performance of cement-stabilised materials is complex (Lv et al 2021), material with cement content from 3% to 4%, loaded to a stress level of 0.5 generally reached between 1 and 10 million load cycles in terms of flexural fatigue after 28 days of curing (Xie et al 2018).…”

Calculation Method of Permanent Deformation of Asphalt Mixture Based on Interval Number

“…Impollonia et al [ 20 ] proposed an interval assessment method for the static response of axial stiffness structures, which overcomes the defects caused by dependence in traditional analysis. Xie et al [ 21 ] used the interval parameters in order to establish the fatigue characteristics model under different stress states, and realized the fatigue characteristic standardization model based on the new interval analysis method, which solved the problems of insufficient sampling performance, low precision and insufficient stability of test equipment. In order to realize the calculation of parameters with boundaries but uncertain sizes, Guerine et al [ 22 ] proposed an interval analysis method of dynamic response from a wind turbine gear system; Long et al [ 23 ] proposed an interval analysis method of fatigue crack growth life prediction; and Liu et al [ 24 ] proposed an interval uncertainty analysis method of structural static response.…”