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Marshall stability of porous asphalt mixture incorporating kenaf fiber

Jasni Nur Ezreen, Masri Khairi Azman, Jaya Ramadhansyah Putra, Abdullah Mohd Mustafa Al Bakri, Razak Rafiza Abd, Nabiałek Marcin, Błoch Katarzyna, Śliwa Agata

Archives of Civil Engineering

2022

Vol. 68, nr 1

379--393

Porous asphalt mixture (PA), known as open-graded surfaces over a stone bed underneath, allows water to go through. These factors can affect the porous asphalt mixture adhesive strength. The high amount of course aggregate promotes the structure of air voids have certain impacts on the acoustic properties of porous asphalt. The materials properties are consisting of both aggregate and bitumen tests. This study also details out the aggregates sieve analysis test to develop new aggregate gradation for PA. According to five ASEAN countries’ specifications, the sieve analysis test was done. The countries included are Malaysia, Vietnam, Thailand, Singapore, and Indonesia. The test for the binder includes the softening point, penetration, and ductility. This study also investigates the addition of kenaf fiber in the mixture as an additive. Mechanical performance test for PA using Marshall Stability test to identify the strength and the properties of the conventional PA with the addition of kenaf fiber compared to the new gradation of PA incorporating kenaf fiber. From the results, the addition of 0.3% kenaf modified PA improved the performance of PA in terms of Marshall Stability and volumetric properties.

Włókna roślinne jako zamienniki włókien mineralnych w kompozytach termoplastów – wizja Forda czy Al Gore'a?

Kijeński J., Kijeńska M., Osawaru O.

Polimery

2016

T. 61, nr 7-8

467--473

Artykuł stanowi wieloaspektową analizę celowości i możliwości zastępowania kompozytów tworzyw termoplastycznych z napełniaczami mineralnymi kompozytami zawierającymi włókna roślinne. Analizę przeprowadzono w odniesieniu do kompozytów polipropylenu, szeroko stosowanych i dobrze scharakteryzowanych pod względem właściwości użytkowych. Wykazano, że entuzjastyczne oczekiwania związane z możliwością wykorzystania termoplastów napełnionych włóknami roślinnymi z szeroko dostępnego odnawialnego surowca, jako tanich materiałów o atrakcyjnych właściwościach, nie są w pełni uzasadnione. Realnym rozwiązaniem jest natomiast otrzymywanie takich kompozytów do niezbyt wyrafinowanych zastosowań z odpadowych poliolefin i odnawialnego materiału włóknistego, pochodzącego z odpadów przemysłu rolnego i leśnego.

An extensive analysis of the possibilities and goal in the application of composites as an alternative to thermoplastic polymer composites filled with minerals has been presented. The analysis was made taking into special consideration the mechanical properties and applicability of polypropylene composites, which are widely used and well characterized. It was shown that the enthusiasm and expectations linked with the vision of the application of thermoplastics filled with plant fibers from widely available renewable sources as cheap materials with attractive properties has not been fully justified. The realistic solution would be maintaining the production of these new materials derived from waste polyolefins and renewable fiber materials from agriculture and forestry industries for low-end applications.

Kompozyty polistyrenu z włóknami roślinnymi i proszkami mineralnymi

Steller R., Żuchowska D., Meissner W.

Kompozyty

2001

R. 1, nr 2

242-245

Przedstawiono niektóre problemy związane z zastosowaniem włókien konopi, lnu i proszku tritlenku glinu jako napełniaczy do odpadowego ekspandowalnego polistyrenu. Stwierdzono, że włókna roślinne i napełniacz mineralny poprawiają wytrzymałość statyczną polimeru przy pewnym spadku wytrzymałości dynamicznej (udarności). Włókna, których efektywność jest bardzo zbliżona, dają bardziej wyraźną poprawę właściwości statycznych niż tritlenek glinu. Użycie wszystkich badanych napelniaczy zwiększa lepkość kompozytów, a w przypadku włókien intensyfikuje też zachowanie nienewtonowskie.

Polystyrene and its copolymers are widely used in industry. Their contribution both to polymer production and polymer waste exceeds 10%. A relatively small part of this contribution (2%) falls to expandable polystyrene, but due to the very low density its waste becomes comparable with the total volume of other polymer waste. Additionally, the expandable polystyrene has a lower molecular weight, and hence the worse mechanical properties, in comparison with typical polystyrenes. It results in a number of serious problems connected with the management, e.g. recycling, of the waste. One of the possible ways of expandable polystyrene recycling is its modification. In this study the expanded polystyrene waste after densification with the two-roll-mill at ca. 120"C during 2 minutes and grinding was blended with hemp or flax fibers or with Al2O3 powder. The process was also carried out with the two-roll-mill at temperature 160°C during 10 min. The fiber in amount of 0:30% or the powder in amount of 0:20% was added to the molten polystyrene. The components were blended until the homogeneous blend was obtained. The samples for mechanical testing were prepared from grind by injection molding at 190°C. The Theological properties were measured using the grind. The relatively low temperatures and shear rates (shear stresses) on every processing stage were indispensable to prevent the polystyrene and plant fibers from strong thermomechanical degradation. The mechanical properties and melt flow index of waste polystyrene-plant fibers blends are presented in Table 1. The same properties of a standard polystyrene are given for comparison. It is evident from Table 1 that there are no significant differences in properties due to the kind of fibers. Both hemp and flax increase the static mechanical properties, especially the tensile and flexural strengths. The impact strength (dynamic property) shows a minimum at 10% fiber content. The impact strength is generally lower than that for pure polystyrene. The lack of dynamical toughening can be attributed to the loss of continuity of polystyrene phase and a weak adhesion between polymer and fiber. The rheological measurements have shown that the flow curves of polystyrene-fiber systems at 170,190 and 210°C can be adequately described by the power law. The constants K and n of the power law determined with a capillary rheometer are summarized in Table 2. Figures 1 and 2 present examples of the flow curves of polystyrene-hemp and polystyrene-flax compositions at 170°C. It can be seen that with increasing fiber content the constant K increases and the constant n decreases. It means that the fiber addition rises the viscosity of the system and simultaneously causes its rheological behavior more non-Newtonian. The qualitatively similar effect brings the temperature lowering. Table 3 presents the comparison of mechanical and rheological properties of waste and standard polystyrenes filled with Al2O3 powder. It can be seen that the powder addition increases the tensile strength (static property) and decreases the impact strength (dynamic property) and the flowability of the system in both cases. This behavior is similar to the systems with fibers discussed previously. However, for waste polystyrene blends a stronger tensile strength rise and a weaker impact strength fall than that for the standard polystyrene can be observed. It testifies probably to a better adhesion between polymer and powder in blends with waste polystyrene, which is due to its lower molecular weight. It follows from Tables 1 and 3 that the plant fibers are more efficient toughening agents for the waste polystyrene than the Al2O3j powder. A further improvement of their efficiency is possible by the simultaneous use of other modifications such as the addition of thermoplastic elastomers and preparation of the fiber surface with suitable adhesives.