ABSTRACT
In recent years, there has been a growing interest in cold asphalt emulsion mixture (CAEM) due to its numerous advantages, including reduced CO2 emissions, energy savings, and improved safety during construction and application. However, CAEM has often been considered inferior to hot mix asphalt (HMA) in terms of performance. To address this issue and achieve desirable performance characteristics, researchers have been exploring the modification of CAEM using high-cost additives like ordinary Portland cement. In this study, the focus was on investigating the effects of utilizing waste alkaline Ca(OH)2 solution, ground granulated blast-furnace slag (GGBFS), and calcium carbide residue (CCR) as modifiers to enhance the properties of CAEM. The aim was to develop an innovative geopolymer geopolymer-based cold asphalt emulsion mixture (GCAE). The results of the study revealed that the use of waste alkaline Ca(OH)2 solution led to an increase in early hydration, which was confirmed through scanning electron microscopy. Furthermore, the experimental findings demonstrated that waste alkaline Ca(OH)2 solution significantly contributed to the rapid development of early-age strength in GCAE. As a result, GCAE showed great potential for utilization in pavement applications, particularly for roads subjected to harsh service conditions involving moisture and temperature. By exploring these alternative modifiers, the study highlights a promising avenue for enhancing the performance of CAEM and potentially reducing the reliance on expensive additives like ordinary Portland cement. The development of GCAE has the potential to offer improved performance and durability in pavement applications, thus contributing to sustainable and efficient road infrastructure.
ABSTRACT
The aim of this research was to develop a sustainable and ecologically sound, non-traditional cold mix asphalt (CMA) that can be used in the construction industry. This new type of CMA incorporates wastewater sludge fly ash (UFA) and bottom ash (UBA) as a replacement filler for ordinary Portland cement and limestone. Silica fume (SF) was also used as an additional filler. The mechanical and durability characteristics of the new CMAs were examined in terms of indirect tensile stiffness modulus (ITSM), and rutting, fatigue, water and fuel resistance. The results showed that CMA with 2.1% OPC +3.9% UFA at 3 days of age, had ITSM values 11 times that of traditional CMA, while CMA with 2.1% OPC+ 3.3% UFA +0.6% UBA, had ITSM values 5 times that of traditional CMA at 28 days of age. SF activated hydration for both mixes, significantly increasing ITSM. These results indicate that CMA has a comparable mechanical performance to standard Hot Mix Asphalt (HMA) mixtures for use as surface pavement layers. This study offers a novel CMA with improved mechanical performance. It is economically effective and ecologically beneficial, compared to HMA, due to its ability to accommodate wastewater sludge ashes that are often disposed of in landfill sites.
