A comprehensive model for predicting thermal cracking events in asphalt pavements

Abstract

A compressive model for predicting thermal cracking events in asphalt pavements that accounts for the continuous evolution of the asphalt mixture properties with oxidative ageing over time has been developed. The model also considers temperature-dependent coefficient of thermal contraction (CTC) for the calculation of thermal strain in the asphalt layer. An improved pavement temperature profile estimate has been employed in the model to predict the required hourly pavement temperature data. The temperature data at the desired depth in the asphalt layer are then used in a kinetic-based ageing model to predict growth in the carbonyl (CA) of the asphalt binder over time. Using a refined one-dimensional constitutive linear viscoelastic relationship, the hourly thermal stress is then computed considering the changes in the viscoelastic and thermal contraction properties of the asphalt mixture with the increase in CA of asphalt binder used in the mix. The required age-dependent relaxation modulus is obtained from the dynamic modulus (E * ) of asphalt mixtures (i.e. in complex domain) at various ageing levels. Also, the required age and temperature-dependent CTC is obtained from thermal strain measurements of varied aged asphalt mixtures using the uniaxial thermal stress and strain test (UTSST). The cracking events are detected over the service life by comparing the predicted thermal stress with the age-dependent crack initiation stress (CIS) of the asphalt mixture. The age-dependent CIS is obtained from the UTSST results for different ageing periods. Preliminary analysis of the model revealed the accuracy of the model in a realistic prediction of the accumulative thermal cracking events for the asphalt pavement with different air void levels (4, 7 and 11%) and with unmodified (PG64-22) and polymer-modified (PG64-28) asphalt binders in a selected location.

Effects of Geometry and Loading Mode on the Stress State in Asphalt Mixture Cracking Tests

“…From the perspective of prevention, thermally induced loading is hardly affected by human factors compared with mechanical-induced loading, which can be easily controlled by limiting the wheel load of trucks. Therefore, the asphalt thermal cracking analyzer (ATCA) test [44], uniaxial thermal stress and strain test (UTSST) [45], and asphalt concrete cracking device (ACCD) test [37] were developed for the optimized selection of materials with improved resistance to thermal shrinkage cracking. Since cracking propagation is an important property for understanding the cracking mechanism of pavements, Mandal and Bahia [46] also proposed to test notched samples in a restrained configuration.…”

An equation-based multiphysics modelling framework for oxidative ageing of asphalt pavements

“…Due to the lack of field measurements, the thermal properties of the pavement layers were collected from the literature [36][37][38][39][40][41][42][43][44][45][46][47], and the current study employed the mean values of those obtained from the literature. Table 1 lists the thermal properties used for each pavement layer in this study.…”

Thermal contraction coordination behavior between unbound aggregate layer and asphalt mixture overlay based on the finite difference and discrete element coupling method

“…When the temperature drops, especially if a large thermal gradient is induced, there will be a huge thermal contraction stress in the asphalt mixture layer due to the constraint from the boundary condition and the base layer (Sun, 2020). Once the accumulated thermal stress becomes greater than the strength threshold of the asphalt mixture, the pavement will crack (Alavi, 2014). Currently, many investigations have been conducted to study the thermal cracking mechanism of asphalt binders and mixtures (Canestrari et al., 2015; Feng et al., 2021; Y. Tan et al., 2012).…”

“…proposed that the thermal cracking of asphalt mixture is the result of the interaction between thermal shrinkage and thermal relaxation (Sun et al., 2023). However, it is a complex mechanical behavior not only attributed to the viscoelastic properties of asphalt mixture and the environment but also the constraint circumstances of the base layer, which rarely gets attention (Alavi, 2014; Dave et al., 2013). The temperature failure of asphaltic pavements is largely ascribed to thermal stress induced by the constraints of the base layer (Sun et al., 2018).…”

“…However, the granular base is discrete and exhibits nonlinear elastoplastic properties (Liu et al., 2013; Y. Zhang et al., 2018). Multiple linear shear springs or nonlinear interfacial friction models have been introduced to represent the constrained behavior of the base layer (Alavi, 2014; Timm et al., 2003) while ignoring the function of the whole structure layer and the discrete property of the unbound aggregate base layer.…”