Embracing Sustainability in Rigid Pavement Construction: Unveiling Geopolymer Concrete’s Potential with Incorporated Reclaimed Asphalt Pavement Aggregates

Abstract

Reconfiguring practices within the construction industry through the utilization of diverse industrial byproducts is a crucial endeavor. This study was devoted to promoting sustainable construction methodologies while mitigating environmental implications. The focus of the research was the incorporation of reclaimed asphalt pavement (RAP) aggregates into GPC for application as pavement quality concrete (PQC). Leveraging fly ash (FA) and ground granulated blast furnace slag (GGBS) as viable aluminosilicate sources emerged as a judicious strategy for formulating blends that exhibit exceptional attributes at ambient temperatures, thereby circumventing the challenges posed by impractical on-site oven curing. Natural coarse aggregates were replaced with RAP at varying percentages ranging over 25% to 100% and the performance of the binders was assessed across a range of NaOH molarities (10M to 16M). The 14-M, 50% RAP mix exhibited superior strength and durability, achieving permissible compressive and flexural strength after just 7 days of ambient curing (41.80 and 4.72 MPa, respectively), in contrast to the 28 day of curing required for conventional cement concrete. This designed mix also showcased significant resistance to surface abrasion and carbonation, along with exemplary thermal stability as determined by thermogravimetric analysis (TGA). Upon exposure to a 2% H2SO4 concentration (to gauge performance in aggressive environments), higher RAP replacement levels revealed to influence mass and strength loss, but the effect of molarity remained quite moderate. Furthermore, toxicity characteristic leaching potential (TCLP) tests confirmed the immobilization of heavy metals in GPC blends with integrated RAP, thereby endorsing their environmental suitability for the construction of rigid pavements.