Use of Superpave Technology for Design and Construction of Rubberized Asphalt Mixtures

Abstract

The effect of different mixing times and mixing temperatures on the performance of asphalt-rubber binder was evaluated. Four different types of asphalt-rubber binders and neat asphalt were characterized using the Strategic Highway Research Program (SHRP) binder method tests. Subsequently, mix designs were carried out using both the SHRP Levels I and II mix design procedures, as well as the traditional Marshall mix design scheme. Additionally, performance testing was carried out on the mixtures using the Superpave repetitive simple shear test at constant height (RSST-CH) to evaluate the resistance to permanent deformation (rutting) of the rubberized asphalt mixtures. Also, six rectangular beams were subjected to repeated bending in the fatigue tester at different microstrain levels to establish rubberized asphalt mixtures’ resistance to fatigue cracking under repeated loadings. The results indicate that the Superpave mix design produced asphalt-rubber contents that are significantly higher than values used successfully in the field. Marshall-used gyratory compaction could not produce the same densification trends. Superpave mixture analysis testing (Level II) was used successfully for rubberized asphalt mixtures. Results clearly indicated that the mixture selected exhibited acceptable rutting and fatigue behavior for typical new construction and for overlay design. Few problems were encountered in running the Superpave models. The results of the RSST-CH indicate that rubber-modified asphalt concrete meets the criteria for a maximum rut depth of 0.5 in.; and more consistent results were measured for fatigue performance analysis using the repeated four-point bending beam testing (Superpave optional torture testing). The cycles to failure were approximately 26,000 at 600 microstrain.

Investigation of Modification of Petroleum Bitumen by Rubber Waste

“…Жақсартылған өнімділігі бар резеңке-асфальтбетон қоспасын алу үшін айналу тұтқырлығы пайдалану тұрғысынан модификация процесінде оңай басқарылатын физикалық параметр болып табылады. Шын мәнінде, каучуктың белгілі бір температурада битуммен әрекеттесуі қоспаның тұтқырлығының максималды мәнге дейін жоғарылауын және реакция уақытымен кейіннен айтарлықтай төмендеуін білдіреді [21]. Осылайша, құрғақ процесті жүргізу оңайырақ, ал ылғал процесс неғұрлым күрделі болса да, алынған байланыстырғыштың реологиялық қасиеттерін дәл реттеуге мүмкіндік беретін артықшылыққа ие.…”

A Review of the Utilisation of Recycled Waste Material as an Alternative Modifier in Asphalt Mixtures

“…CRM is a waste scrap tires disposed of in trash dumps, and each year about 1.5 billion tires are manufactured globally [37]. The use of crumb rubber in the design of asphalt pavements has reduced the amount of waste in the United States, where about 10% of the asphalt [38]. Figure 4 shows the crumb rubber waste material before and after recycling.…”

“…The dry process makes use of rubber as an aggregate. Typically, 2% to 3% rubber is prepended with the aggregates before charging the mixture with a pure asphalt binder [38]. However, the impact is mainly binder based, rubber content increases; the ITS value decreases.…”

Modeling of asphalt-rubber rotational viscosity by statistical analysis and neural networks

“…The wet process is used to obtain the well known asphalt rubber. In this process 15-25% of tire rubber (in relation to binder weight) reacts with asphalt under high temperature (170-200 °C) for a specific period of time to produce a material suitable for use as binder in almost all paving applications [14][15][16][17][18][19][20] .…”