Feasibility of Using a Lignin-Containing Waste in Asphalt Binders

A lot of water waste streams are produced during the production of hardboard panels. This paper analyses the feasibility of using a lignin-containing waste from the hardboard industry in asphalt binders. It would contribute to both waste reduction and decrease of the consumption of asphalt in order to obtain environmental, economic and social benefits. The waste from the hardboard industry was not subjected to any transformation i.e. it was blended directly with the conventional asphalt. Asphalt binder samples blended with 0, 5, 10, 20 and 40% of the waste were aged in a rolling thin-film oven apparatus. Basic characterisation (penetration grade, ring and ball softening point and resilience) as well as advanced characterisation (dynamic viscosity, shear complex modulus and phase angle) were performed. Asphalt binders blended with up to 20% waste can be stored, pumped and handled at hot-mix asphalt facilities. Addition of the waste to asphalt binder increases the viscosity and the shear complex modulus and reduces the phase angle. The waste produces asphalt binders with higher storage modulus and lower loss tangent. The waste enhances fatigue and rutting resistance. Asphalt binder with 20% of waste displays the best potential for use as an extender and as well as an enhancer in asphalt pavements. The research results can offer technical support to value this waste from hardboard production, without the need for subsequent transformations.