Abstract
Aggregate is an indispensable raw material for asphalt pavement construction. This study evaluates the influences of aggregate morphological characteristics on the high- and low-temperature viscoelasticity of asphalt mixtures. Based on simplex lattice mixture design (SLD), asphalt mix samples were designed and prepared with the same gradation but three different types of aggregates. Subsequently, three morphological characteristics of aggregate (roundness, perimeter index, and erosion-dilation area ratio) are presented to characterize fine and coarse aggregates. Then based on Burgers viscoelastic model, uniaxial compression static creep test was carried out to analyze the high-temperature viscoelastic properties for asphalt mortar and mixture. Meanwhile fitting Prony series models have been utilized to represent relaxation modulus conversed from creep compliance and the low-temperature relaxation characteristics can be also discussed. The experimental results indicated that morphological characteristics of aggregate, especially fine aggregates, are strongly correlated with the viscoelastic parameters of asphalt mixtures. However, the complex morphological characteristics of aggregates have opposite influences on the high- and low-temperature viscoelastic parameters. Therefore, when considering both high- and low-temperature viscoelastic properties, the aggregate proportion was optimized for the appropriate morphological characteristics, which will provide a reference for asphalt mixture design.
Highlights
IntroductionAggregate is an important raw material and it directly affects the performances of asphalt pavement engineering, which is highly related to the efficiency of asphalt pavement maintenance [1]
Aggregate is an important raw material and it directly affects the performances of asphalt pavement engineering, which is highly related to the efficiency of asphalt pavement maintenance [1].Aggregate in asphalt mixtures generally accounts for approximately over 90% by weight, which plays a major role for its stability, durability, and mechanical properties.Researchers have constantly developed research methods to study the aggregates morphological characteristics
Uniaxial failure test was theeach applied stress compression level of 0.2 MPa wascreep kept constant for thecompression uniaxial compression creep conducted to determine an appropriate stress level for asphalt mortar
Summary
Aggregate is an important raw material and it directly affects the performances of asphalt pavement engineering, which is highly related to the efficiency of asphalt pavement maintenance [1]. Researchers have constantly developed research methods to study the aggregates morphological characteristics. Wilson and Klotz [2] presented a method of measuring angularity using Hough transform for quantitative analysis of aggregate angularity. Kuo et al [3] used a digital image-analysis method to investigate the coarse aggregates morphologies and quantified the morphological characteristics in an effective way. Masad and Button [4] investigated the angularity and texture of fine aggregates by using erosion-dilation method and form factor, in which angularity is analyzed by high-resolution images and texture is described by low-resolution images. Kuo and Freeman [5]
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