Back analysis of the multilayer cylindrical HMA samples – height reduction method

ABSTRACT

Although the complex modulus is one of the most basic properties used in pavement analysis and design, its accurate measurement for existing pavement layers has always been a challenging task. When samples cut out from the pavement asphalt layers are used for the hot mix asphalt (HMA) complex modulus tests, they are performed separately for each layer. This paper describes an original method for determining the complex moduli of individual asphalt layers. The new idea is tested by applying uniaxial loading–unloading cycle tests to the HMA specimens combined of multiple layers. It was observed that changing the thickness ratios in samples' layers, allows obtaining the sets of load and displacement values (F, u), which effectively enlarge the database needed for the back analysis. For now, the conducted analysis presented in the paper focused on numerical modelling of HMA specimens. The simulated numerical testing conditions were based on viscoelastic parameters of asphalt concrete samples whose values were determined in real laboratory tests. In the case of noisy results of laboratory test simulations with a stochastic Gaussian process, by applying multiple cuts and changing sample's height, the determined values of stiffness moduli of the individual layers do not vary from the reference values by more than 10%.

KEYWORDS:

• Back analysis
• HMA
• multilayer samples
• height reduction
• complex modulus

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

A. Pożarycki http://orcid.org/0000-0002-1321-066X

P. Górnaś http://orcid.org/0000-0002-0632-4191

D. Wanatowski http://orcid.org/0000-0002-5809-0374

Additional information

Funding

This work has been partially supported by the Polish National Centre for Research and Development [grant number 244285] entitled ‘Precise system of the load capacity parameters identification of roadway structure in predicting the lifetime of road pavements’. The fourth author would like to acknowledge the financial support from the National Natural Science Foundation of China [grant number 51408326].