Stabilized base courses are an indispensable part of today's pavement structures. Stabilized mixtures as we know them consist of high-quality crushed aggregate bound with a hydraulic binder, usually cement. Due to their composition, stabilizing mixtures increase the strength and stiffness of the pavement structure, which is expressed by modulus of elasticity, i.e., the measure of the stiffness of the pavement structure due to dynamic loading.
Although classic stabilized mixtures meet the criteria of load capacity, stiffness and durability, the modern approach in road construction is changing. Namely, in order to meet requirements of sustainable development, it is necessary to use alternative, waste materials.
Wood ash, a by-product of the combustion of wood biomass in the production of electricity and thermal energy, has been shown through various studies to be a potentially valuable and non-standard material that can be used in road construction. Wood ash can improve the properties of stabilizing mixtures (as strengths or modulus of elasticity) and can contribute to reducing the amount of cement required in the stabilized mixture.
This paper describes the determination of the elasticity modulus on stabilized mixtures containing sand, cement and wood ash by a non-destructive ultrasonic method. The mixture of sand and ash was stabilized with different amounts of cement. The aim of the work was to determine the dependence of the modulus of elasticity value on the stabilized mixture composition. This study also established a correlation between the modulus of elasticity and the ultrasound velocity. These test results show the improvement of stabilized mixtures properties as well as the importance of ultrasonic method in assessing properties and quality of stabilized mixtures.

wood ash, elasticity modulus, stabilized mixtures, ultrasound velocity, pavement structure