Influence of GGBFS and Processed Coarse RAP in Pavement Quality Concrete

Due to scarcity of virgin aggregates, the use of reclaimed asphalt pavement (RAP) as a substitute for natural aggregates has gained popularity. Despite the fact that RAP is recycled in asphalt pavement, there is still excess RAP, and its use in concrete pavements has expanded in recent years. According to a survey, 95 percent of India’s pavement is bituminous pavement. As a result, the maintenance and reconstruction of such pavements generate RAP, which can be reused in concrete pavements as well as surface course, base course, and subbase of flexible pavements. Various studies on the properties of reclaimed asphalt pavement and its optimal requirements for usage in concrete have been conducted throughout the years. In this study, a total of eight concrete mixes with various proportions of processed coarse RAP (20%, 40%, and 60%) and a fixed percentage (40%) of GGBFS with different proportions of processed coarse RAP were prepared to enhance the interfacial transition zone in PQC. A study of fresh properties like slump value; hardened properties like density; mechanical properties like compressive strength, split tensile strength, and flexural strength; durability properties such as abrasion resistance; and time-dependent properties such as shrinkage of PQC mixes was carried out in the present study. The new processing technique enhanced the properties of RAP inclusive PQC mixes and the strength of all the concrete mixes was above the design target strength. It was observed that there was a reduction of more than 60% in the binder content of RAP aggregates as a result of the processing of RAP. The partial replacement of cement by GGBFS also enhanced the properties of concrete mixes. However, with the increase in the percentage of replacement levels of RAP, the properties of concrete mixes were slightly reduced, but the reduction was much less. Based on the strength and durability properties of PQC, it was concluded that GGBFS with processed coarse RAP aggregate up to 40% can be used in pavement quality concrete (PQC). Hence, this study proves to be effective in the utilization of process RAP aggregates with GGBFS in PQC.