This paper presents finite element analysis of 4-layered flexible pavements embedded visco-elastic asphalt concrete (AC) top layer and controlled low-strength materials (CLSM) sub-layers as well as graded crushed stone subgrades layers subjected to sinusoidal and impulsive surface wheel loads. Two-dimensional deformation assumption is employed. Time-dependent stress-strain relations are treated using Laplace transform based on correspondence principle. Scheme based on fast Fourier transform (FFT) is employed for inversion of Laplace transformed to obtain time-domain results. A typical 4-layered pavement is analyzed in which relaxation modulus of top visco-elastic asphalt layer is expressed in Prony series. Two kinds of CLSMs, i.e., CLSM-B80/30% and CLSM-B130/30% are compared with graded crushed stones and AC used for base materials. Time-domain responses of vertical displacement and stress at bottom of AC layer are compared. The vertical settlements using CLSM bases (B80/30% and B130/30%) are smaller than that using graded crushed stones even considering visco-elastic behavior of asphalt layer and show to be good materials employed as base substitutes for graded crushed stone in flexible pavement design.
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