Field Evaluation of High Reclaimed Asphalt Pavement–Warm-Mix Asphalt Project in Florida

Abstract

In December 2007, a portion of State Route 11 in Deland, Florida, was milled and repaved with 45% reclaimed asphalt pavement (RAP). These high RAP mixes were produced at lower than normal hot-mix temperatures and with foamed warm-mix asphalt (WMA) technology. This project was the first large production in which the Florida Department of Transportation (DOT) allowed the use of high RAP in combination with WMA. FHWA, in cooperation with Florida DOT and the National Center for Asphalt Technology, was on site for production and placement of the high RAP-WMA. Plant-produced mix was collected by FHWA for performance testing evaluation. Two mixes were produced: a high RAP–hot-mix asphalt (HMA) control mix and a high RAP-WMA mix. Performance tests conducted by FHWA included performance grade (PG) determination of binders, dynamic modulus, and flow number. PG results of the binders indicate that the high RAP-WMA mix is softer than the high RAP-HMA control mix. This is further confirmed by flow number results, where the high RAP-WMA mix had a lower flow number than the high RAP-HMA control mix did. Dynamic modulus results indicate that the high RAP-WMA mix is slightly softer than the high RAP-HMA control mix, especially at intermediate temperatures. Comparison of measured dynamic modulus results with those predicted using the Hirsch and Witczak models confirm that complete blending occurred in the high RAP-HMA control mix. However, incomplete mixing of RAP and virgin binders may have occurred in the high RAP-WMA mix.

Avaliação da durabilidade de misturas asfálticas a quente e mornas contendo material asfáltico fresado.

“…Outros estudos também foram desenvolvidos a fim de proporcionar um melhor entendimento dos pavimentos com misturas mornas que incorporem percentuais de RAP acima de 25% (MALLICK et al, 2008;COPELAND et al, 2010;DOYLE;HOWARD, 2010;MOGAWER et al, 2011;OLIVEIRA, 2013 NAVARO et al, 2012;El BÉZE et al, 2012;NAHAR et al, 2013;NGUYEN, 2013;BOWERS et al, 2014 classificam o CAP quanto à sua consistência por penetração à 25°C.…”

“…Diversos estudos têm mostrado a viabilidade técnica da combinação WMA e RAP, mas alguns autores afirmam que avanços precisam ser realizados para a produção deste tipo de mistura em grande escala (MALLICK et al, 2008;COPELAND et al, 2010;DOYLE e HOWARD, 2010).…”

“…Dessa forma, um ligante novo apropriado, misturado à quantidade correta de aditivo para mistura morna, é capaz de regenerar o ligante do RAP para um nível em que a rigidez da mistura será comparável ao de uma mistura virgem (MALLICK et al,2008). Copeland et al (2010) produziram mistura morna reciclada com 45% de RAP, usando técnica de mistura asfáltica morna com espuma. Este foi a primeira produção em grande escala autorizada pelo DOT da Flórida usando mistura morna com elevado teor de RAP.…”

“…Além disso, a mistura WMA-RAP é ligeiramente menos rígida que mistura HMA_RAP, especialmente em temperaturas intermediárias (COPELAND et al, 2010).…”

“…Quelques études ont été réalisées afin d'évaluer les conséquences de l'incorporation d'agrégats dans les enrobés sur leurs performances (AL-QADI et al, 2007;AURANGZEB et al, 2014;BENNERT et al, 2014;COPELAND et al, 2010;DONY et al, 2013). L'étude de l'efficacité du mélange du vieux bitume Etant donné que le taux de recyclage dépend fortement du niveau d'homogénéité des agrégats, il a été décidé de séparer nos agrégats en quatre classes granulaires, afin de mieux en contrôler la recomposition.…”