Effect of one-part geopolymer filler on the performance of cold bitumen emulsion mixtures

This study aims to assess the performance of cold bitumen emulsion mixtures modified with a one-part geopolymer based on blast furnace slag and an alkaline activator. This material is generally prepared in a liquid solution, from an aluminosilicate source and an alkaline compound, and is dedicated to the precast sector. In this study, it was obtained by mechanosynthesis, a solvent-free process consisting of high-energy ball milling. The powder was incorporated as a filler in the formulation of 0/10 asphalt mixes. Other cold mixtures with limestone and blast furnace slag filler were manufactured to evaluate the influence of the additive nature on the cohesive strength at different curing times, compressive strength, water sensitivity, rutting resistance and resilient modulus. The potential chemical reactivity between each filler and each emulsion was monitored by in situ Fourier transform infrared spectroscopy. The results pointed out that the cohesive strength of the mixes containing one-part geopolymer is two to three times higher than that of the other formulations after 24 h curing. High compressive strength of the one-part geopolymer-based mixes is noticed; however, their compressive strength ratio is slightly lower, in comparison with the other mixes. The rutting percentage of the one-part geopolymer-based mixes reaches 4% at 30,000 cycles and their resilient modulus above 6,000 MPa at 15 °C. These results are attributed to the geopolymerisation reaction occurring between the filler and the emulsion, traduced by a shift in infrared spectroscopy. Therefore, the addition of one-part geopolymer filler, produced according to a non-solvent process, is a promising solution to enhance the implementation and durability of cold mixtures. © 2024 Informa UK Limited, trading as Taylor & Francis Group.