Characterization of Stabilised Sewage Sludge for Reuse in Road Pavement

In recent years, the disposal of sewage sludge has been a major concern worldwide because of their potential treat in relation with the contamination of ground water and food chain. Furthermore, their poor mechanical properties don’t allow a possible direct use in civil engineering applications. For these reasons, it was important to explore more opportunity to reuse this by-product of sewage treatment. In this frame, the solidification-stabilisation technique (S-S) which is based on hydraulic binders can improve the properties of sewage sludge so that it can be used in civil engineering application, especially in road pavements. In this context, this paper investigates the possibility of using the solidified sludge in road construction. To achieve this goal, an experimental protocol was conducted using a several combined binders: combination of Cement/Limestone filler and Cement/Lime, with different amounts in the target to fix the optimal mixtures amount. Several tests were conducted to characterise the mechanical and geotechnical properties of the solidified sludge. The results indicate that the solidified sludge using a combined mixture of cement and lime allows a possible use as base and sub-base layer

Mechanical and durability properties of concrete incorporating glass and plastic waste

The main objective of this work is to contribute to the valorization of plastic and glass waste in the improvement of concrete properties. Waste glass after grinding was used as a partial replacement of the cement with a percentage of 15%. The plastic waste was cut and introduced as fibers with 1% by the total volume of the mixture. Mechanical and durability tests were conducted for various mixtures of concrete as compressive and flexural strengths, water absorption, ultrasonic pulse velocity, and acid attack. Also, other in-depth analyses were performed on samples of each variant such as X-ray diffraction (XRD), thermogravimetric analysis (DSC-TGA), and scanning electron microscope (SEM). The results show that the addition of glass powder or plastic fibers or a combination of both in concrete improved in the compression and flexural strengths in the long term. The highest compressive strength was obtained in the mix which combines the two wastes about 26.72% of increase compared to the control concrete. The flexural strength increased in the mixture containing the glass powder. Therefore, the mixture with two wastes exhibits better resistance to aggressive sulfuric acid attack, and incorporating glass powder improves the ultrasonic pulse velocity