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The increase in the cost of virgin materials and the environmental sustainability have contributed to increasing the incentive to use asphalt mixtures containing high percentages of recycled asphalt pavement (RAP). However, the use of high percentage of RAP into virgin asphalt mixture could negatively affect the performance of some properties of asphalt mixtures. Thus, using an appropriate additive to offset the negative effect of RAP could lead to an increase in the amount of RAP in asphalt mixtures. Therefore, this study aimed to evaluate the effect of using glass fiber (GF) with different contents (0.0%, 0.1%, 0.2%, and 0.3%) as an additive on the performance of asphalt mixtures containing RAP materials (60%, 70%, and 80%) and rejuvenated with waste engine oil (WEO) i.e., 6%, 9%, and 12%. The performance of RAP mixtures incorporating GF was evaluated using the indirect tensile strength test (ITS), resilient modulus test, and moisture susceptibility test. Hamburg wheel track testing was done to evaluate the rutting performance of the 70% RAP mixture. The results showed that the GF modification enhanced the ITS, rutting resistance, moisture susceptibility, and resilient modulus of rejuvenated mixtures. It was also found that the GF content of 0.2% was the optimum. [ABSTRACT FROM AUTHOR]

Highlights • We reviewed the asphalt mixes modified with lignin fiber and glass fiber. • Studied of rutting, water damage, thermal and fatigue cracking in asphalt mixes. • Lignin fiber improves the resistance to low temperature cracking in asphalt mixes. • Glass fiber improves the high temperature performance in asphalt mixes. • Both fibers improve fatigue performance and water stability in asphalt mixes. Abstract Low temperature thermal cracking, rutting, moisture damage and fatigue cracking are popular damages that appear in the asphalt mixture. These problems occur mainly because of the growth in the number of heavy load vehicles, design and construction errors and environmental condition that reduce the quality, performance and the service life of the pavement. Several previous studies showed that using additives like fibers to modify asphalt mixtures could enhance the efficiency and boost the quality and service life of the pavement. This paper presents a review of the role of lignin and glass fiber as a modifier in bituminous mixes. To evaluate some main mixture properties, some tests such as the low temperature bending, indirect tensile strength, the wheel loading tracking, Hamburg wheel tracking, Marshall immersion, freezing-thaw splitting, third-point bending fatigue and indirect tensile fatigue are applied to analyze rutting, low temperature cracking resistance, moisture damage resistance and fatigue resistance of asphalt mixture modified with lignin or glass fiber. Results denoted that the quality of asphalt mixture enhanced significantly by adding lignin fiber or glass fiber. Previous researches demonstrated an obvious improvement in low temperature performance in the pavement when adding 0.2–0.4% lignin fiber of asphalt mixtures, with a limited improvement of high temperature performance. On the contrary, the asphalt mixtures modified with 0.2–0.6% glass fiber of asphalt mixtures significantly improved the resistance of high temperature. So it is hard to improve all the performances of the mixture by using only a single admixture at the same time. Thus, a new way of modifying asphalt mixture that is called double-mixture technology or composite modification, which is able to enhance the overall properties of asphalt mixture. [ABSTRACT FROM AUTHOR]

In the Hamburg cold atom experiment with orbital states in an optical lattice, s- and p-orbital atomic states hybridize between neighboring sites. In this work we show how this alternation of sites hosting s- and p-orbital states gives rise to a plethora of different magnetic phases, quantum and classical. We focus on phases whose properties derive from frustration originating from a competition between nearest and next nearest neighboring exchange interactions. The physics of the Mott insulating phase with unit filling is described by an effective spin-1/2 Hamiltonian showing great similarities with the J1–J2 model. Based on the knowledge of the J1–J2 model, supported by numerical simulations, we discuss the possibility of a quantum spin liquid phase in the present optical lattice system. In the superfluid regime we consider the parameter regime where the s-orbital states can be adiabatically eliminated to give an effective model for the p-orbital atoms. At the mean-field level we derive a generalized classical XY model, and show that it may support maximum frustration. When quantum fluctuations can be disregarded, the ground state should be a spin glass. [ABSTRACT FROM AUTHOR]