Development of Mix Designs for Minimally Refined Reclaimed Asphalt Pavement (RAP) Concrete for Florida Concrete Test Road

Abstract

Abstract:The main objective was to develop mix designs for concrete incorporating minimally processed reclaimed asphalt pavement (RAP) materials to be used in the Florida Concrete Test Road. The laboratory program was conducted in two phases. Phase I involved testing of twelve (12) trial mixes to identify feasible mixes which could meet the Florida Department of Transportation (FDOT) specification requirements for pavement concrete. Based on the preliminary test results from the trial mixes, ten (10) production mixes were identified and evaluated more extensively in Phase II to establish the optimum concrete mixes incorporating RAP to be recommended. Concrete mixtures, with 0% to 40% RAP as aggregate replacement and using 20% fly ash and 50% slag as cement replacement, were designed using the optimized aggregate gradation (OAG) technique instead of the American Concrete Institute (ACI) method. Among the RAP concrete evaluated, the 20% RAP concrete mixes with 0%, 20% fly ash, and 50% slag as cement replacement were able to meet Florida Department of Transportation's (FDOT) over-design compressive strength of 29 MPa (4200 psi) at 28 days. Using 20% and 40% RAP in concrete could result in saving in the total cost of aggregate by 9% and 17%, respectively. When the RAP is not refined (e.g., no washing of RAP, and no separating of coarse and fine portions), it is recommended that 20% of RAP can be used as aggregate replacement in pavement concrete.

The Design and Material Characterization of Reclaimed Asphalt Pavement Enriched Concrete for Construction Purposes

“…If more than 25% of RAP is used, higher stiffness of aged asphalt leads to structure cracking even at low temperatures and a higher inclination to fatigue compared to fresh raw materials [19]. Additionally, about 85.1 million tons of RAP was stockpiled in the U.S. in 2015 [8,20] and, in comparison, about 50 million tons of RAP is produced annually in Europe [13,14]. Notwithstanding, only limited research papers focused on the investigation of RAP as a potential candidate for natural aggregates replacement can be found [15,21,22].…”

Micromechanism of the Dispersion Behavior of Polymer-Modified Rejuvenators in Aged Asphalt Material

“…In recent years, many pavement materials have reached the end of their service life and have been abandoned in the city (Figure 1). Therefore, developing more effective and durable recycling technologies to rejuvenate this waste asphalt concrete is important for sustainable urban construction [4][5][6].…”

Role of Aggregate Gradation in Balancing the Performance of Asphalt Concrete Mixtures

“…As aggregate gradation significantly effects the volumetric and mechanical properties of AC mixtures, an optimized aggregate gradation must be selected to produce a BMD. Han et al used the optimized aggregate gradation method (OAG) to design an AC mix providing the densest packing of the aggregate (15). The method allowed the use of a smaller quantity of cementitious materials to achieve a good constructability, workability, and was also economical.…”