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The performance and the fundamental weaknesses of the asphalt mix have made the researchers think about modifying the technical properties of the asphalt mix by using the appropriate additives. The fiber spreads through the asphalt mix and prevents the development of the micro-cracks by producing a more coherent mix and increasing its durability. The present study, for the first time, has used two additives, lignin and glass fiber (6 and 12 mm in length), to improve the performance of asphalt mix. Mixing was done in a way that lignin and glass fiber were added to the bitumen and aggregates, respectively. According to the results, the length of the used glass fiber has a significant effect on the Marshall Resistance and asphalt mix performance so that glass fiber in 6 mm length has reduced the Marshall strength and glass fiber in 12 mm length has increased the Marshall strength. Moreover, the results of resilient modulus indicate that having a stable percentage of fiber and an increasing lignin percentage, it behaves differently at two temperatures of 15 and 25 ∘ C, confirming once again the fact that the length of fiber plays a decisive role on the result of resilient modulus. [ABSTRACT FROM AUTHOR]

Open-Graded Friction Course mixture (OGFC) has a gap-graded aggregate that results in highly air voids. This structure provides higher permeability by allowing water to flow through it. Although these mixtures have good drainage properties, they exhibit poor strength with a short life span. Because of their poor performance, there is a lack to be used in pavement application. Attempts had made to increase mixture performance; one of these methods is by using fibers or polymers. The objective of the current study is to determine if modified OGFC mixes with different polymers and fibers have comparable performance. Polymers and fibers were used in OGFC mixes to evaluate their performance. Steel fiber, glass fibers, Polyvinyl chloride (PVC) and Phenol resin were investigated in this study. The modified mixtures were tested by indirect tensile strength, Marshall and permanent deformation tests. Results showed that fibers decrease rutting by 19% and they have more effective than polymers that decrease rutting by 7%, and glass fiber was found to be more effective with a 24% reduction in permanent deformation than other additives to enhance performance. [ABSTRACT FROM AUTHOR]

This study presents an experimental overview of thermoplastic polymer-coated glass fibre and scrap-reinforced hot-mix asphalt (HMA) mixtures. The toughening effects of the reinforced HMA mixtures were characterised using indirect tensile and Hamburg wheel-tracking tests. The indirect tensile loading tests were used to calculate the relative indirect tensile strengths of samples and to compare their moisture susceptibilities. The fibre’s relative contributions to increasing the indirect tensile strength and the resistance to rutting are quantified by comparing the maximum indirect peak tensile stress and tensile strength ratio (TSR). The indirect tensile strength and TSR of the fibrous mixtures are nearly two times higher than those of the plain mixtures, demonstrating the lower moisture susceptibility and superior field performance of the fibrous asphalt mixture. Accelerated rutting tests using the Hamburg wheel test setup for the fibrous mixtures caused at least three times more loading passes to be required to reach the rut-depth criteria compared to the number of loading passes required for the plain mixtures. [ABSTRACT FROM AUTHOR]

• AE could effectively classify the damage stages of asphalt mixture. • The main fracture of asphalt mixture was postponed after the fibers added. • Steel fiber showed superior cracking resistance of asphalt mixture. Fibers have been proven to enhance the stability and mechanical strength of asphalt mixture, but different fibers exhibited diverse characteristics of reinforcement effect. This study is set out to investigate the fiber reinforcement effect of asphalt mixture containing glass fiber reinforced asphalt mixture (GFRAM), basalt fiber reinforced asphalt mixture (BFRAM), and steel fiber reinforced asphalt mixture (SFRAM). The control asphalt mixture (CAM) was also fabricated for comparison. The fiber content was 0.5% by weight of the asphalt mixture and the specimens were manufactured following the Marshall compaction method. Indirect tensile test (IDT) and acoustic emission (AE) test at low temperature were conducted simultaneously to characterize the fracture resistance of different types of fiber reinforced asphalt mixture (FRAM). The amplitude, count, rise angle (RA), average frequency (AF), and b-value were obtained based on AE signal analysis to evaluate FRAM's reinforcement effect. The results revealed that the addition of fibers dramatically improved the strength of CAM, and the occurrence of the main fracture in FRAM emerged later than CAM. SFRAM exhibited more favorable anti-cracking performance than GFRAM and BFRAM based on the comprehensive AE signals analysis. [ABSTRACT FROM AUTHOR]

Lignin and glass fiber were used as additives to improve the quality of road pavements and minimize moisture damage and cracking at low temperatures on asphalt pavement, according to a previous laboratory study. The aim of this paper is to make a significant contribution to the environmental assessment of the construction of road pavements using four types of asphalt mixtures based on the life cycle assessment (LCA) methodology according to the requirements of ISO 14040, considering the impact of raw material extraction, asphalt mixture manufacturing, transportation, and wearing surface construction. The results of the environmental assessment showed that all studied asphalt mixtures do not offer any improvement in all impact categories, and three modified asphalt mixtures have a slight negative effect in all impact categories. The composite mixture has the highest negative effect of the studied three modified asphalt mixtures in all categories except in the marine aquatic ecotoxicity potential category and freshwater aquatic ecotoxicity potential category, where the lignin modified asphalt mixture has the highest negative effect in these two categories but has the best environmental impacts on most of other impact categories. Furthermore, the negative effect caused by composite asphalt mixtures is minimal and thus can be used to improve the overall performance of asphalt pavement. [ABSTRACT FROM AUTHOR]

• The indirect strength of fibrous mix is 39.4% higher than the plain mix. • The rut-depth of fibrous mixtures satisfied the 12.5 mm specification of TxDOT. • The glass fiber is utilized as a strengthening material for the 50% recycled asphalt mixture. This study presents strengthening effect on the reclaimed hot-mix asphalt concrete associated with the reinforcement of hybrid rod-shaped glass fibers and ball-shaped glass-fiber powder to the mix. The toughening effects of the reinforced mixtures were characterized using indirect tensile, dynamic modulus, and hamburg wheel-tracking tests. The rod-shaped hybrid fibers, coated by the polypropylene resin, consist of the macro dimension of rod-shape glass fiber in 10–15 mm of length and the relatively micro size of the fiber in 4–6 mm of length separately. The ball-shaped glass fiber powder, which was coated by the polyethylene resin, was mixed with the macro and micro rod-shape fibers and the reclaimed hot-mix asphalt concrete. The indirect tensile strength test of the fibrous mixtures resulted in about 1.4 times higher strength than those of the plain mixtures. Lower moisture susceptibility, better performance of dynamic modulus at low and high temperatures and superior rut resistance of the fibrous asphalt mixtures were also observed. [ABSTRACT FROM AUTHOR]