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Physical Modified Bitumen

Modified binders have the ability to offer improved performance over conventional binders. Benefits that may be derived from binder modification and typical conditions where such binders should be considered, the polymer dosages and mix designs of the binder are selected, to ensure optimum performance to the climatic and traffic conditions that, prevail on a particular project. Their main application is waterproofing. Extensive research has shown that, the use of performance asphalts using polymer modified bitumen binders significantly increases stability and strength properties and longer life-span, as demanded by the industry to meet today’s and tomorrow’s traffic conditions. Two methods are commonly used to incorporate polymers into asphalt. Polymer- bitumen emulsion that is relatively easy and trouble free. Addition of solid polymers to asphalt with agitator. This method normally requires substantial mixing and shearing in order to uniformly disperse the polymers, particularly when SBS or SIS block copolymers are used. Some benefits of PMB are higher resistance to weight or pressure, surface remains smoother for longer time, resistance of aging due to high temperatures, less cracking in low temperatures and less affected by moisture over time.The PMB can be categorized into two board classes.

 

 Elastomeric

 

The main ingredient of these bituminous membranes is refined bitumen and the basic polymerispolymerized (Styrene Butadiene Styrene). The addition of elastomeric materials (SBS) makes the mixture more elastic, and thus able to adjust more easily to any compressing and expanding that may occur, while at the same time it is extremely resistant to low temperatures.Membranes are reinforced with a polyesteric non-woven fabric, which gives to the final product good mechanical strengths, as for instance tensile strength, dynamic and static compressive strength. Coating of the membranes, that are intended for the final layer of a water insulating system, with mineral gravels, protects them from the ultraviolet rays and helps increase their life span. ASTM test method is common for these kinds of bitumen. Some additives which are common to use are Styrene – butadiene – styrene (SBS), Styrene – butadiene – rubber Natural rubber and Crumb tire rubber.


    Plastomeric     

The main ingredient of these bituminous membranes is refined bitumen and the basic polymeris atactic polypropylene. The addition of plastomeric polypropylene resins (APP) makes the mixture more plastic and resistant to high temperatures and ultraviolet radiation. Some of the common additives are atactic polypropylene (APP), polyethylene (PE), polypropylene (PP), polyvinyl chlorid.