Developing a Novel Cold Bitumen Emulsion Mixes by Adding Geopolymer

Abstract

Cold bituminous emulsion mixtures (CBEMs), which are less costly, need less energy, and are more environmentally friendly, maybe can take the place of hot mix asphalt (HMA) in the future. It is known, that these mixtures have a very low initial strength, requiring longer curing times and more susceptibility to moisture damage. Geopolymer is often used in the fields of concrete and soil improvement performance. It has not been used in the field of asphalt mixtures; so, this study can be considered as the first time of using it. This study tried to make a new CBEM by incorporating the Geopolymer into the mix to improve its initial performance and enhance early strength. Geopolymer was created inside CBEM by activating the fly ash using an alkali solution. Three percentages of fly ash (1, 3, and 5%) were used for creating Geopolymer; and different curing periods (3, 7, and 14 days) were also used. Marshall stability and Indirect Tensile Strength tests were conducted to assess the mechanical properties of mixtures. The results showed that Geopolymer can be a promising material for creating cold mixes with a better initial strength compared to traditional cold mixes. Comparing CBEMs with (5% FA + 0% CF) to control CBEMs, the increase with MS was approximately (32% at 3 days, 43% at 7 days, and 37% at 14 days). The performance of cold mixes was enhanced by the addition of Geopolymer with different FA contents and curing times when compared to control CBEMs. This improvement was particularly noticeable at longer curing times and higher fly ash contents.