Showing papers on "Rubberized asphalt published in 1976"

Rubberized asphalt paving composition and use thereof

Abstract: The dissolving and/or dispersing of relatively large proportions of reclaimed rubber into molten paving asphalts is facilitated by incorporating into the asphalt a minor proportion of a highly aromatic, high-boiling, high-flash-point mineral oil. The resulting mixtures can be held at temperatures above 300° F for substantial periods of time without becoming too viscous for convenient handling, thereby facilitating the application thereof to roadways. The rubberized asphalt mixtures are particularly useful in the form of stress absorbing membrane interlayers between old, damaged pavement surfaces and an overlayer of new asphalt concrete, for providing chip-seal coatings over old pavement, as crack fillers in Portland Cement concrete or asphalt concrete pavements, and bridge deck waterproofing membranes.

Process of producing a rubberized asphalt composition suitable for use in road and highway construction and repair and product

Abstract: Process of providing a rubberized asphalt from reclaimed rubber produced from whole scrapped tires and having a composition of about 15-20 percent acetone extractible oils, resins, and other rubber compounding ingredients such as antioxidants, antiozants, emulsifiers, and the like, about 10-35 percent carbon black, about 10-20 percent ash primarily from zinc oxide, titanium dioxide, clay, whiting, and talc, and about 35-45 percent rubber hydrocarbon of which 15-30 percent is a mixture of synthetic rubbers such as SBR, neoprene, polybutadiene, isoprene, butyl, and chlorobutyl, and other 10-20 percent is natural rubber and an asphalt at a level of 5-25 percent rubber to 75-95 percent asphalt by weight, the asphalt having a composition of 20-30 percent asphaltenes, 5-15 percent nitrogen bases, 10-20 percent first acidaffins, 30-40 percent second acidaffins, and 10-20 percent paraffins, and the rubber and asphalt being cooked at about 350-450 degrees F. for 30 minutes to 2 hours, which improves the adhesion of the asphalt, reduces stripping, and improves the strength and flexibility of the asphalt; and the product so formed. Asphalts having less than 30 percent second acidaffins content do not produce the desired adhesive properties when combined with rubber and those that contain more than 40 percent of this component become soft and sticky at summer pavement temperature. Also a process for producing a rubberized asphalt product suitable for joint and crack sealing, membrance, chip seals, and as a binder for asphaltic concrete, and having a viscosity of less than 800 centipoises at 400° F. and being sprayable using conventional equipment may be provided as may the product itself. It may be provided by cooking at 350°-450° F. for 30 minutes to 2 hours, a composition containing 20-60 percent reclaimed ("devulcanized") rubber, 15-20 percent high rubber scrap, 15-50 percent of a scrap rubber crumb having a somewhat lower rubber content, and an asphalt composed of 20-30 percent asphaltenes, 5-15 percent nitrogen basis, 10-20% first acidaffins, 30-40% second acidaffins, and 10-20 percent paraffins; the rubber-asphalt proportion being 5-25 percent rubber to 75-95 percent asphalt by weight.

Flexible rubberized asphalt membranes for inverted roofing systems

Abstract: A laboratory test method, based on the "toughness" value of the material, has been developed to distinguish between high- and low-performance rubberized asphalt membranes used in inverted (protected-membrane) roofing systems. Rubberized asphalts with a high toughness level have been shown, under laboratory conditions, to be capable of bridging structural cracks in concrete decks at temperatures as low as -18°C (0°F). When the temperature is raised, the membrane remains as an undeformed continuous film. On the other hand, membranes with a lower toughness level were shown to fail at high strain rates, while at lower strain rates they sag irreversibly after such a temperature cycle. During application of the membrane, such temperatures may be experienced for short periods of time before the insulation is placed on top of the membrane or before the building is heated. Field experience in waterproofing applications, including bridge decks, underground parking garages, and plazas as well as roofs, has shown that the toughness level, combined with other properties such as low temperature flexibility, resistance to flow, and penetration, correlate well with actual performance.

Cold-Applied Fluid Elastomeric Waterproofing Membranes

Abstract: The uses of cold-applied fluid elastomeric membranes for waterproofing are discussed, particularly in comparison with other means of waterproofing. The features of the available types of membranes are discussed: coal tar/polymer, asphalt/polymer, rubberized asphalt, and emulsion membranes. Finally, a series of drawings show the optimum design features for the use of these membranes, including the details of preparation for application.