Feasibility of using recycled waste travertine stone powder (RWTSP) as a substitute for mineral filler in microsurfacing surface treatment

Each year, a significant amount of construction waste (CW) is produced globally, creating a major environmental challenge for its proper disposal. Utilizing recyclable CW in pavements not only helps address environmental issues but also conserves non-renewable materials. This study aims to investigate and assess the effectiveness of substituting recycled waste travertine stone powder (RWTSP) as a mineral filler (MF) in the microsurfacing surface treatment mixing plan. Initially, the physical and chemical properties of the materials used in asphalt were evaluated. The performance of the microsurfacing treatment was then examined through tests including wet cohesion, wet track abrasion, loaded wheel-displacement, and loaded wheel-sand adhesion, conducted using five different combinations (RWTSP0 +MF100, RWTSP25 +MF75, RWTSP50 +MF50, RWTSP75 +MF25, and RWTSP100 +MF0) in accordance with ISSA A143 guidelines. Additionally, FESEM-EDS, o, and FTIR tests were performed to assess particle shape, analyze material surface, identify constituents, determine structure, and examine organic compounds, chemical bonds, functional groups, and molecular structure. The results indicated that mixes containing RWTSP filler improved the performance of microsurfacing. This is attributed to RWTSP filler's high percentage of CaO and SiO2, as well as its more uneven and rough surfaces compared to mineral filler. For instance, in an 8% bitumen mix, the blend containing 100% RWTSP increased cohesion at 30 and 60 min by 30.8% and 30.7% respectively, improved abrasion resistance by 50%, and reduced mixture bleeding by 10.3%. Moreover, this mix enhanced resistance against vertical and lateral displacements by 32.1% and 34.4% respectively. Finally, ANOVA analysis revealed that RWTSP filler, bitumen, and material interaction were key factors influencing the performance of microsurfacing.