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Only in Europe, every year around 29 million tons of plastic waste are generated and only about 35% of such waste is collected for recycling. This results in huge amounts of plastic waste threatening the environment. One of the possible solutions for disposal can be represented by the concrete industry. Several research works have already studied the use of plastic waste in concrete mix as partial replacement for aggregates, showing that this use of plastics can contribute to reducing the environmental impact of concrete production by saving non‐renewable resources. At the same time, lightweight concrete can be produced but at a non‐negligible cost of a mechanical strength reduction. This work aims at investigating the effects on concrete physical and mechanical performances resulting from the introduction of recycled plastic aggregates in combination with another kind of waste used as filler, namely biochar. Biochar, which is the solid carbonaceous by‐product resulting from wood‐waste pyro‐gasification, can have the role of carbon sequestrating additive in concrete, being able to fix carbon in a stable form in buildings for decades. The experimental findings obtained in this work show that the combination of biochar and recycled plastic waste, which was never investigated before, can help to obtain concretes with satisfactory mechanical performance, which promote circular economy principles. Thanks to biochar addition, the reduction in mechanical properties due to the presence of plastics is extremely limited with respect to control; moreover, these concretes demonstrate better behavior in terms of fracture energy and ductility. [ABSTRACT FROM AUTHOR]

Permanent deformation, fatigue and thermal cracking are the three typical distresses of flexible pavement. Using hydrated lime (HL) into the conventional limestone mineral additive has been widely practiced, including in Europe, to improve the mechanical properties of hot mix asphalt (HMA) concrete and as the result the durability of the constructed pavement. Large number of experimental studies have been reported to find the optimum addition of HL for the improvement on HMA concrete mechanical properties, moisture susceptibility and fatigue resistance. Pavement in service is under complex thermomechanical stress-strain conditions due to coupled atmospheric and surrounding environment temperature variation and the traffic loading. To predict and analyse the performance of pavement structures the data only from uniaxial compressive test for the resilient modulus and permanent deformation would be not enough. However, so far, the data of HL modified HMA concrete under complex loading conditions are still not well informatively complete. To contribute new knowledge, this paper reports an experimental study of both uni- and tri-axial tests for the asphalt concrete using HL into mineral additive for the mixes designed for the applications of wearing, levelling, and base layers, respectively. All the tests were conducted under three controlled temperatures and four stress deviations. The test results have showed that, for all three types of mixes, the permanent deformation of the HL mixes is less than the ones of no HL addition. The degree of the improvement on permanent deformation resistance using HL is much pronounced at high stress deviation states. The results have also showed that the resilient modulus strongly depends on the temperature and stress deviation while the mixes of HL addition demonstrate higher rigidity. At last, mathematical characterization models have been proposed for the measured material properties. A numerical simulation case study has been performed to test and demonstrate the application of the proposed unified property model. • Experimental work on uni- and tri-axial tests for asphalt concrete mixes using and without using the hydrated lime filler modification. • Novel mathematical characterization modelling on the experimental results for the resilient modules and permanent deformation. • Numerical case study simulation to demonstrate the application of the mathematical model proposed and developed in this work. [ABSTRACT FROM AUTHOR]