# Evaluation of the Long-Term Performances of SMA-13 Containing Different Fibers
###### Abstract  
To clarify the influence of fiber type on the long-term performance of stone music asphalt (SMA), this paper used basalt fiber (BF) and lignin fiber (LF) to modify SMA-13 (SMA with aggregate nominal maximum particle size of 13.2 mm) asphalt mixture. The pavement performances (high-temperature performance, cracking resistance at low and medium temperature, and water stability) of the two kinds of fiber-reinforced SMA-13 were checked under different aging degrees (unaged, short-term aged and long-term aged), scanning electron microscope (SEM) test was conducted to explain the strengthening mechanism of the fibers. Fourier transform infrared spectrometry (FTIR) was used to analyze the changes in the chemical composition of asphalt after aging. The results of the wheel tracking test and uniaxial penetration test showed that the high-temperature performance of the BFSMA-13 (defined as the SMA-13 containing BF) is better than that of the LFSMA-13 (defined as the SMA-13 containing LF) at different aging degrees. The high-temperature performance of BFSMA-13 increases with the increase of the aging degree, while the aging process decreases the high-temperature property of LFSMA-13. The results of the three-point bending test and semi-circular bending (SCB) proved that BFSMA-13 is more capable of deformation and less prone to cracking at low and medium temperatures. The results of the immersion Marsh test indicated that BF can better improve the strength and the water stability of the SMA-13 mixture than LF. The SEM images showed that basalt fibers form a solid three-dimensional network structure in the mixture which could contribute to the strengthening of the mixture. The results of infrared spectroscopy analysis showed that styrene-butadiene-styrene (SBS) degrades during asphalt mixture aging, and that the chemical composition of asphalt changes more after aging in LFSMA-13 than in BFSMA-13. The conclusions of this study help toward further understanding of the performance changes of the SMA-13 mixture during its service life and to guide the selection of fiber additives for SMA-13 mixtures. s 28 April 2021 31 May 2021 1 June 2021 11 June 2021 11 1545 145  
similar fibers, such as straw composite fiber [9], bamboo fiber [10], and cellulose fiber [11], were also evaluated for SMA. Such plant fibers could absorb extra free asphalt. However, some researchers argued that the asphalt absorbed by these fibers is just a waste of money because the absorbed asphalt does not contribute to the mixture strength [12]. Additionally, these plant fibers may lose the ability to absorb free asphalt gradually because it could degrade due to the oxidation during the service life [13; 14]. Apart from plant fibers, many researchers have studied kinds of polymer synthetic fibers for SMA, such as polyester fiber, polypropylene fiber, and so on [15; 16; 17]. They believe that polymer fibers and asphalt are chemically similar and that they can synergize well with the forces. However, some researchers have found that polymer fibers tend to curl at high temperatures, which weakens their function in the mixtures. [9] Additionally, glass fiber is another type of stabilizers used for SMA. Some researchers concluded that fatigue behavior of asphalt concrete reinforced by glass fiber exhibits positive influences [18; 19]. Some researchers also found that the brittleness of glass fibers causes it to break easily when mixed with mineral aggregates [20], and the smooth surface of glass fiber leads to poor adhesion with asphalt. Basalt fiber (BF) is a new kind of inorganic fiber developing in recent years [21; 22]. It is made from basalt stone at 1450 \({}^{\circ}\)C, and the production process does not produce any harmful by-products. Nowadays, BF has been paid more and more attention in the asphalt pavement engineering due to its excellent technical performance and environmental benefits [23; 24; 25]. [PERSON] found that basalt fiber can better improve the performance of SMA-13 mixture than other fibers [26].