Influence of Fiber Type and Dosage on Tensile Property of Asphalt Mixture Using Direct Tensile Test

Abstract

In engineering practice, fiber addition is a frequently used method to improve the tensile property of asphalt mixture. However, the optimum fiber type and dosage have not been determined by direct tensile tests. In this paper, monotonic tensile tests were conducted on three kinds of stone mastic asphalt (SMA13) mixtures, that is, granular-lignin-fiber-reinforced SMA (GFSMA), flocculent-lignin-fiber-reinforced SMA (FFSMA), and basalt-fiber-reinforced SMA (BFSMA) at different fiber dosages to probe the influence of fiber dosage on their tensile mechanical indexes (tensile strength, ultimate strain, elastic modulus, and strain energy density) and to determine the optimum dosage of each kind of fiber. The results showed that with the elevation of fiber dosage, the tensile strength, elastic modulus, and strain energy density of all three kinds of asphalt mixtures increased first and then decreased, while the ultimate strain increased constantly. The optimum dosage was 0.50 wt%, 0.45 wt%, and 0.50 wt% for granular lignin fiber, flocculent lignin fiber, and basalt fiber, respectively. On this basis, strain-controlled direct tensile fatigue tests were conducted on the three kinds of asphalt mixtures at the corresponding optimum fiber dosage. The results indicated that asphalt mixture reinforced with 0.50 wt% granular lignin fiber exhibited ideal direct tensile fatigue performance with respect to fatigue life and accumulative dissipated energy. Therefore, granular lignin fiber is recommended as the favorable fiber type, and its optimum dosage is 0.50 wt%. Moreover, scanning electron microscopy (SEM) demonstrated that the essence of the impact of fiber dosage and type on the tensile property of SMA is whether the reinforcement effect on the mixture matrix outweighs the negative effect of the defects between fiber and mixture matrix, or whether the reverse applies.

Characterization, Applications and New Technologies of Civil Engineering Materials and Structures

“…Diao et al selected hydrated lime and basalt fiber to prepare a modified asphalt mixture to enhance the fatigue resistance of aging asphalt pavement [13]. Yang et al conducted monotonic tensile tests on three kinds of stone-mastic asphalt mixtures to determine the optimum dosage of each kind of fiber [14]. Civil materials and structures are essential to engineering, but are very vulnerable to harsh environments, freeze-thaw actions, loading, etc.…”

Bonding Mechanical Properties between SMA Fiber and ECC Matrix under Direct Pullout Loads

“…Shape memory alloy (SMA) is a kind of functional material with special shape memory effect and superelasticity which has been used in aerospace, automobile, robot, biomedicine, civil engineering, and other fields [ 16 , 17 , 18 , 19 , 20 ]. Superelasticity is a characteristic of austenitic SMA material produced by stress excitation at normal temperature.…”

Enhancing the Performance of Asphalt Mastic with Natural Fiber Reinforcement: Basalt and Bamboo Fibers

“…The addition of basalt fibers to asphalt mixtures can strengthen the mixture and effectively improve its high and low-temperature performance. Many studies have been conducted to investigate the reinforcing properties of basalt fibers on asphalt mixtures, including mechanical behavior, low and high-temperature performance, and water sensitivity [10][11][12][13]. Qin X et al suggested that compared with lignin fiber and polyester fiber, basalt fiber had a more significant impact on improving the performance of asphalt mortar [14].…”