Investigating the effect of addition of olive husk ash on asphalt binder properties

Flexible pavement is the preferred pavement type in construction of roads and highways. A huge amount of non-renewable materials and industrial products like Olive Husk Ash (OHA), aggregates, bitumen, cement, lime, and other additives are used during the construction and maintenance of the pavement system. Needless to say, the extraction and production of these materials are unmaintainable. Moreover, the wastage of materials, the worsening environmental conditions, the insufficient resources, and the increasing cost of material urged the researchers to look for alternative materials that can be used in flexible pavement. Jordan as many other Mediterranean countries produces a substantial amount of olive oil every year, which in turn produces an enormous amount of olive waste that could lead to environmental problems. Up to now, there is no efficient or certain way in which olive oil waste could be handled or used except that it is sometimes used for heating purposes. The current research aims to evaluate the effects of Olive Husk Ash (OHA) on asphalt binder properties such as penetration ductility, softening point, fire and flashpoint, and specific gravity. In the current research, OHA is used as an additive (0%, 5%, 10%, 15%, and 20%) of asphalt-cement. Tests on OHA-asphalt binder properties are conducted and results are reported. Results of experimentation and analyses indicate that increasing OHA content in the asphalt-cement binder has resulted in a reduction of both penetration and ductility and an increase in specific gravity, softening point, and fire and flashpoint.