High Temperature Stability Of Asphalt Mixture Research Articles

Effect of dry desulfurization ash as a filler on asphalt pavement performance

This study aims to explore the feasibility of using dry flue gas desulphurization ash (DFGDA) as a filler in asphalt pavements. Two DFGDA materials were added into the base asphalt with different mineral powder proportions to prepare asphalt mastic and mixture, and the pure mineral powder asphalt mastic and mixture were used as the blank control group to evaluate the properties of DFGDA-doped asphalt mastic and mixture. The results show that the addition of DFGDA can improve the high-temperature rheological property and reduce the low-temperature rheological property of asphalt mastic; similarly, the high-temperature stability of asphalt mixture can be greatly improved, while its low-temperature performance and water stability are reduced; despite these decreases, all outcomes still meet the requirements of relevant specifications. No chemical reactions are observed between DFGDA and asphalt, indicating that the physicochemical properties of fillers are responsible for the change in the properties of DFGDA-doped slurry and mixture. Notably, the DFGDA-added asphalt mixture does not bring additional negative effects to the environment. Based on cost analysis, the high-quality use of DFGDA in asphalt mixture can save direct material costs of about $920,000 per 100 kilometers of asphalt road construction. In summary, the application of DFGDA in the asphalt mixture can not only meet the basic performance requirements of asphalt pavements but also greatly save material costs and protect the environment.

Analysis of Coupling Effect and Heavy Load of High-Temperature Stability of Asphalt Mixture

To study the variation in the high-temperature stability of asphalt mixtures under extreme high temperature and heavy load, rut tests and analyses were carried out with both the APA (asphalt pavement analyzer) test and CLWT (Chinese wheel load test). In this paper, the relationship model between the dynamic stability of asphalt mixtures and the temperature, load, and binder viscosity is established; this model provides a method for evaluating the temperature stability of asphalt mixtures under nonstandard temperature conditions. The results revealed that the dynamic viscosity of an SBS-modified asphalt binder showed an exponential relationship with temperatures varying from 55°C to 70°C. Under a temperature condition from 55°C to 70°C and a pressure of 0.7 MPa, the dynamic stability of the asphalt mixture increased linearly with increasing temperature. The dynamic stability of the asphalt mixture exhibited a temperature inflection point at 65°C, and the decay rate was increased. The APA test results, which were used to evaluate the anti-rutting performance of the asphalt mixture on the basis of the ratio of the rutting depth difference to action times from 6000 to 8000, showed a good correlation with the CLWT test results. With a high temperature of 65°C and the pressure increasing from 0.7 MPa to 1.3 MPa, the dynamic stability of the asphalt mixture exhibited exponential decay. The variation laws of dynamic stability with temperature, load, and asphalt binder viscosity were revealed by complex logarithmic variation.

Experimental study on high-temperature stability of rubber powder-modified Asphalt mixture

Waste rubber powder-modified asphalt can not only improve the asphalt pavement performance but can also solve the environmental pollution problem caused by waste tires. In this paper, through rutting tests, the effects of three different factors, the rubber powder content, rubber powder mesh number, and hydrogen peroxide content, on high-temperature stability of the mixture are systematically studied. The results reveal that the optimum rubber powder mesh is 60 mesh and the best rubber powder content is 21% for high-temperature stability of a rubber-modified asphalt mixture. At the same time, hydrogen peroxide can improve the high-temperature stability of the asphalt mixture.

Evaluation of High-Temperature Performance of Asphalt Mixtures Based on Climatic Conditions

The dynamic stability of a rutting test does not optimally reflect the high-temperature stability of asphalt mixtures. In this study, a rutting test was performed over a long duration (4 h) at different temperatures (40, 50, 60, 70 °C) for three asphalt mixtures, namely, matrix AC-16, SMA-16, and modified AC-16 asphalt mixtures. Subsequently, the temperature rutting rate was obtained after considering the annual temperature conditions of Guangdong and Beijing in China. Because the conditions of the rutting test were different from that of the actual pavement, the rut depth was calculated using a modified temperature rutting rate. This modification considered four factors: wheel trace distribution, temperature, pavement thickness, and loading rate. The calculation of the temperature rutting rate considered the climatic conditions and utilized the rutting deformation data from hour 1–4 of the rutting tests, during which the asphalt mixture was in a stable creep period. Thus, the high-temperature stability of the asphalt mixture was reflected more scientifically by the temperature rutting rate than the dynamic stability. The high-temperature rut-resistance of the asphalt mixture was found to improve significantly after the introduction of two additives (anti-rutting agent and lignin fiber). The modified formula for rut depth can realistically predict the annual rutting depth for three asphalt mixtures in a one-way driving pavement.

Study on Verification of Evaluation Indexes of Shear Resistance of Asphalt Mixtures Based on GTM Method

The high temperature performance of asphalt mixtures can’t be evaluated comprehensively by present widely-used rutting tests. In this paper uniaxial penetration test and GTM(Gyratory Testing Machine) method are adopted in order to test, evaluate and make correlation analysis of shear resistance performance of asphalt mixtures at high temperature. Combined with verification results of field investigation, this paper finds the shear strength in uniaxial penetration test at 60℃ and index GSF in GTM method can objectively show the shear resistance performance of asphalt mixture at high temperature and can be used to test the high-temperature stability of asphalt mixtures. Besides, there is a good linear correlation between both and the correlation coefficient R is 0.9597. For the surface or medium layer of asphalt mixture in highways, the shear strength should be no less than 0.7MPa in the uniaxial penetration test at 60℃ and the shear safety factor GSF shall be no less than 1.3 in GTM method.

Effect of air voids on the high-temperature creep behavior of asphalt mixture based on three-dimensional discrete element modeling

This study focused on the effects of different parameters related to air voids on the creep behavior of asphalt mixture based on micromechanical modeling and virtual test through three-dimensional discrete element method (DEM). By using DEM software named as Particle Flow Code in three dimensions (PFC3D), user-defined micromechanical modeling was conducted for asphalt mixture. And virtual uniaxial static creep test of asphalt mixture was conducted by PFC3D and verified by laboratory creep test. The effects of air void content, microstructure parameters including size, elongated index and orientation of air voids, and air void distribution on the creep behavior of asphalt mixture were investigated based on virtual creep test. It is proved that bigger content, size and elongated index of air voids lead to greater creep strain of asphalt mixture. Compared to vertical orientation, horizontal orientation of air voids is more harmful to the creep behavior of asphalt mixture. Nonuniform distribution of air voids within asphalt mixture also has negative effects on the creep deformation of asphalt mixture, especially for vertical nonuniform distribution of air voids. Therefore, guaranteeing and improving the content, distribution and microstructure of air voids within asphalt mixture are important to keep the high-temperature stability of asphalt mixture.

Influence of Loading Time on High-Temperature Stability of Asphalt Mixtures

AbstractCompared with flat slope sections of asphalt pavement, the loading time of low-speed vehicle load to uphill sections with long and large longitudinal slope is much longer, under the compreh...

Evaluation of rutting performance of asphalt mixture based on the granular media theory and aggregate contact characteristics

Based on digital image processing technology, this paper calculates the number of contact points and inclination of coarse aggregates. The asphalt pavement analyzer (APA) is applied to evaluate the rut depth of AC-13F, AC-13C, SMA-13 and MLB-13 asphalt mixtures added different kinds of asphalt. The granular media theory and uniaxial penetration test are introduced to find out the relationship between the number of contact points and shearing strength of mixture; results prove that the number of contact points can logically evaluate the high-temperature stability of mixtures. And both uniform strain model and static model are well predicting the shear modulus. Test results indicate that the high-temperature stability of asphalt mixtures can be defined via the initial number of contact points and variation of inclination. Adoption of T SP (the softening points of asphalt) as model variable is better to describe the relationship among contact points, asphalt performance and rut depth than adoption of rut factor G*/sinδ. The prediction model adopting rut factor G*/sin δ as model variables needs further study and validation. We define N opt as the optimal contact point number and N min as the minimum contact point number, which are supposed to be applied into the mixture design as references for gradation selection.

High-Temperature Stability of Asphalt Mixture with the Influence of Styrene Butadiene Styrene

High temperature stability of asphalt mixture is used to evaluate the performance of asphalt concrete pavement. It is very important for engineers to improve pavement performance by analyzing factors that contribute to high temperature stability for asphalt mixtures. Based on the wheel tracking tests in laboratories, three types of asphalt mixtures with styrene butadiene styrene (SBS) modifier are used to analyze the high temperature performance of asphalt mixtures. It is shown that the optimum contents of SBS modifier would be 5%∼6% in continuous-graded mixtures; Rutting Depth (RD) would reduce and Dynamic Stability (DS) would obviously increase with the increase of SBS modifier; the DS of the coarser asphalt mixtures would be larger than that of the finer mixtures. The coarse aggregate could enhance friction of skeleton structure and mechanical interlocking force among mineral granule so that the shear strength and the high-temperature stability of the hot mixed asphalt mixtures would be significantly improved.