Question

Prepare and submit no more than 4 pages summarizing the description and benefits of only one of the following sustainable asphalt concrete mixtures: 1. Polymer modified asphalt concrete mix 2. Fiber reinforced asphalt concrete mix 3. Warm Mix Asphalt Concrete 4. Open Graded Asphalt Rubber Friction Course The organization of this assignment should be as follow: 1. Cover page including your name, ID, supervisor name, topic title, semester, and the date 2. Introduction and Description 3. Materials and Mix Design Considerations 4. Expected Benefits 5. Conclusion 6. References

Answer 1

FIBER - REINFORCED ASPHALT CON MIX (FRAC) and description Introduction fobox Asphalt containing a mixture of discrete fiber improves and increases the structural integrity of the asphalt. The fibers are distributed uniformly and randomly onented maintaining a pattem to strengthen The asphalt concrete overall. Only 3-4% of fibers is inteoduced to the asphalt mexture to act effectively The different effects of fiber in asphalt: - Encreases the tensile strength - reduces each widths and content the coalk wid the tighty, thus improving durability. - reduces air voids; - a cusproves impact resistance and abrasion resistomie improves thaw resistance reduce the bleeding of water - control the cracking due to plastic shrinkage -improves the resistance to explosive spalling in case of a severe fire. Fundamentally, fiber changes the viswelasticity of the modified asphalt, increases dynanie modulus, moisture susceptibily, Creep compliance, sutting resistance and freeze than resistance, while reduring the reflective Cearking of asphalt mintures and pavements.

Materals and Mix Design Considerations fibers I for introducing. The different methods in Asphalt ment we are : - Doy mex process. - Wet min process Doy men process: The day with the aggregate before cellows for the best siber process mines the fibre adding asphalt. It distribution in the meature UI Wet mix with the minture process : asphalt The wet process blends the fibers prior to incorporating the binder into are: Different fibres used an asphalt elastomer and plastener polymers - polypeoplyene fibers (PP) - polyester fibres - cellulose hibers - carbon fibers - glass fibers - nylon fibers. Design considerations : (6 optimum bending menture - The principle of designing the optimum amount of binder content is to include sufficient amount of bindes so that the aggregates are fully coated with bitumen

voids are and the » Density: sealed up.. Mines with high ng Mines with higher internal resis offers resistance to densification for both wet day men processes except for 3% sobre content a In the day mis sample, the arrangement of aggregates and day polymer reun doesn't allow further densification (3) Stability . It shows the manimum load supported by FRA C. Usually 3-4% of fiber wet mon process will give good stability results when compared with day process (4) Stiffness - It is the measure of the materails resistance to shear stresses , permanent deformation and rutting. High stiffness value indicates a mix with greater ability to spread the applied load. (5) Flow - It is a measure of deformation of the asphalt mix determined during the stability test - Most often 2-4% of the fibre wet min process performed the best than the other proportions and processes

Benefits of FRAC (1) increases the durability of concrete (2) enneases the tensile strength of oneet (6 redues the air voids and waterroids (4) the addition of swall, closely spaced and uniforly dispersed fibers to concrete acts as crack arrester and will improve the static and dynanue propecties, 5 develop good resistance to aging, fatigue cracking , bleeding and reflection chenking. etc., Conclusion The use of fibrees in A mixtures has been involved with three dessemitae tayets: mechanical Pmprovement, preparation of electrically conductive mentures and reating a new market to manage the waste tentile fibers. The two processes, wet process and dey mis process. Generally, the day one is preferred once the other The onentation of febers through the FRAC speumen can be examined with the aid of optical and for scanning election microscopy.