Using Warm-Mix Asphalt Technology to Incorporate High Percentage of Reclaimed Asphalt Pavement Material in Asphalt Mixtures

Abstract

The use of reclaimed asphalt pavement (RAP) helps save natural resources and money. The percentage of RAP that can be utilized successfully in hot-mix recycling is primarily dictated by practical considerations. To avoid deterioration of the aged binder, RAP should not be exposed to relatively high temperatures. This study investigated the feasibility of using a warm-mix asphalt (WMA) additive, Sasobit H8, in successfully recycling hot-mix asphalt (HMA) with 75% RAP at a lower temperature. A control HMA was prepared with extracted aggregates and PG (performance grade) 64-28 binder at 150°C. Another HMA was produced with PG 52-28 binder at 135°C. Two WMA mixes were prepared with Sasobit H8 at 125°C, one with PG 52-28 and the other with PG 42-42 binder. Samples with design asphalt content were compacted by using 75 gyrations of the Superpave gyratory compactor. Their voids, tensile strength at −10°C, rutting potential at 60°C, and moduli at 0°C, 25°C, and 40°C (at different times) were determined and compared. The moduli samples were subjected to 60°C in between the tests. The results show that it is possible to produce mixes with 75% RAP with similar air voids as virgin mixes at lower than conventional temperatures using 1.5% Sasobit. The addition of a significantly lower grade of binder, PG 42-42, at a rate of 1.5% by weight of mix produced a mix that is most comparable with a virgin mix.

Asphalt Pavement Material Improvement: A Review

“…The addition of Sasobit could increase the high temperature grading of the asphalt binder [46]. Latter, Mallick et al (2008) have investigated the feasibility of using a WMA additive, Sasobit, with 75% reclaimed asphalt pavement (RAP) for producing a base course at a lower temperature and found that the performance of WMA with RAP was dependent on the stiffness of the combined (rejuvenated) binder in the mixture [47]. Moreover, have investigated the performance properties of WMA binders (Aspha-Min and Sasobit) containing aged binder.…”

Use of reclaimed asphalt pavement (RAP) in warm mix asphalt (WMA) pavements: a review

“…As a result of this, aggregates are completely coated with the binder at a lower temperature than required for HMA. RAP-WMA mixes utilize lesser virgin material and result in reduced CO 2 emissions and this makes it environment friendly [4,11]. WMA mixes prepared with RAP show similar properties to conventional HMA mixes [12].…”

“…As raw material and petroleum extraction involves huge cost, lot of study is being conducted across the globe to search for new materials which are durable and show good performance at low cost [3]. Using RAP to produce cold or hot mix asphalt is one of the methods which aims at cost reduction [4]. The re-use of aggregates and bitumen present in RAP aids in saving natural resources, money and is eco-friendly [5].…”

Methods to Evaluate the Aging Grades of Reclaimed Asphalt Binder

“…Generally, RAP contents from 10% to 30% by mass of the mixture are considered to be adequate to produce asphalt mixtures with performance similar to conventional mixtures [4][5][6]. Rejuvenators, additives and warm mix asphalt technology are usually employed to improve the effective contribution of RAP binder towards the total binder of the mixture [7][8][9]. However, the use of RAP is at a very low level in many developing countries, for there are no relevant and unified recycling guidelines.…”