scholarly journals From Complex Modulus E* to Creep Compliance D(t): Experimental and Modeling Study

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1945
Author(s):  
Abdeldjalil Daoudi ◽  
Daniel Perraton ◽  
Anne Dony ◽  
Alan Carter
Keyword(s):  
Tensile Test ◽  
Creep Compliance ◽  
Complex Modulus ◽  
Tensile Tests ◽  
Direct Compression ◽  
Creep Tests ◽  
Indirect Tensile Test ◽  
2S2p1d Model ◽  
Indirect Tensile ◽  
Direct Tensile

Creep compliance (D(t)) is a very important input for the thermal cracking resistance in the Mechanistic-Empirical Pavement Design Guide (MEPDG). The aim of the work presented here is to predict the results of creep compliance D(t) from the result of complex modulus E*(ω). The work plan is divided in two main parts: an experimental part consisting of creep tests, and a modeling part. Three configurations were compared together, namely direct tensile, direct compression and indirect tensile tests. The modelling part consists of using a 2S2P1D model coupled to Kopelman approximation to switch from the frequency domain to the time domain. Additionally, 2S2P1D was used to calibrate the generalized Kelvin–Voigt model and get the creep compliance directly from E* results. The experimental results show that D(t) from direct tensile and direct compression are the same in the viscoelastic domain and are greater than D(t) from the indirect tensile test. The indirect tensile test (IDT) seems to be very difficult to achieve compared to the other two variants. The converted results using the 2S2P1D model coupled to Kopelman approximation and the results from the GKV model describe the experimental points very well.

scholarly journals Calculation Derivation and Test Verification of Indirect Tensile Strength of Asphalt Pavement Interlayers at Low Temperatures

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6041
Author(s):  
Qian Zhang ◽  
Zhihe Fang ◽  
Yiheng Xu ◽  
Zhao Ma
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Asphalt Pavement ◽  
Indirect Tensile Strength ◽  
Elastic Theory ◽  
Calculation Formula ◽  
Indirect Tensile Test ◽  
Indirect Tensile ◽  
Direct Tensile ◽  
Direct Tensile Test

When the direct tensile test is adopted to determine the interlayer tensile strength of the asphalt pavements, specimen separation or internal cracking often occurs at the bonding area of the loading head, rather than at the interlaminar bonding interface. In view of the tedious and discrete data of the direct tensile test, this paper attempts to introduce an indirect tensile test to determine the interlayer bond strength of asphalt pavement to solve this problem. However, the indirect tensile test method of a binder lacks the corresponding mechanical theory. This paper deduces the calculation formula of the indirect tensile strength of a binder based on elastic theory. A mechanical model of the test was established with the finite element method. In accordance with the two-dimensional elastic theory and the Flamant solution, an analytical solution of tensile stress in the indirect tensile test is proposed through the stress superposition. On this basis, the calculation formula for the indirect tensile strength of the interlaminar bonding is derived according to Tresca’s law. A low-temperature indirect tensile test was designed and conducted to verify the correctness of the formula. By comparing the results of the indirect tensile test and direct tensile test, it is found that the interlaminar strength of the mixture measured by them is similar, and the dispersion of indirect tensile test results is small. The results show that the indirect tensile test can replace the direct tensile test to evaluate the interlaminar tensile strength.

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