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This study evaluates the utilization of biomass olive oil waste ash (OA) as a concrete paving material. Concrete pavement was produced by replacing a portion of Portland cement with OA at different percentages up to 15%. An additional set of concrete pavement was prepared by incorporating OA with nano-silica (NS) at various contents up to 1.5%. The optimal replacement contents of OA or OA and NS were investigated in terms of workability, compressive strength, strength development rate, and durability. The results showed that the optimal replacement level of OA content was 7.5%. The incorporation of NS with OA increased the optimal replacement level to 15%. The incorporation of NS with OA improved the strength, durability, and workability of all mixes. The utilization of OA with NS at optimal levels can produce concrete pavements. Using NS and OA, approximately 10 % cost savings could be achieved, together with a sustainable, environmentally friendly disposal method of olive oil waste. [ABSTRACT FROM AUTHOR]

This study used rice husk ash to reinforce recycled aluminium waste cans matrix through stir casting technique to produce a composite. The rice husk ash was added to the aluminium matrix in 0, 5, 10, 15, and 20 wt%. Mechanical and microstructural analyses were carried out on the composites. The tensile strength of the composite increases at 5 wt% addition of reinforcement and increases further to reach a maximum of 121.6 MPa at 10 wt% addition. The tensile value then dropped at 15 wt% and reduced further at the 20 wt% particulate addition. A similar trend was observed for the impact strength with the maximum value of 81.5 J occurring at 10 wt% addition before declining at the higher percentages of reinforcement. The hardness of the composites continues to increase as the percentage of the rice husk addition rises leading to the highest Brinell hardness number (BHN) of 74.5 occurring at the highest percentage of rice husk ash addition. The density of the composites decreases as the wt% addition of the reinforcement increases giving the lowest density value of 2.46 g/cm3 at 20 wt% addition. The microstructures exhibited uniformity in the dispersion of the reinforcement into the aluminium matrix, although little particulate agglomeration could be noticed at higher percentages of rice husk addition. This study provides a significant boost to the attainment of lightweight materials in the automobile and other allied industries. The improvement in the mechanical properties and the lower density of the composites attained in this study are vital factors considered in material selection and design for lightweight engineering applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the chemical composition and thermal properties of kaolin, the physical properties of metakaolin, and the mechanical properties of metakaolin-based geopolymers using bemban fiber. Kaolin was calcinated to become metakaolin at 600 ℃ for 2 h for optimum conditions. The chemical composition of kaolin mostly consisted of 59.30% SiO2, 34.30% Al2O3, and 3.06% Fe2O3. The transformation of kaolin into metakaolin with temperature was determined through thermal stability tests and analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Regarding the thermal properties of kaolin, predehydroxylation occurred at 31.07–92.69 ℃, dihydroxylation occurred at 400–600 ℃, and the endothermic peak in the DTA curve was recorded at 505.63 ℃. This research also analyzed the physical and mechanical characteristics of metakaolin-based geopolymers, with the additional variation percentages of bemban fiber alloys resulting from a 3% NaOH alkalization treatment for 2 h. The test results indicate that the bemban fiber improves the physical and mechanical characteristics of geopolymers. This improvement is related to the enhanced geopolymer characteristics, including a water absorption capacity of 1.10%, porosity of 2.32%, compressive strength of 35.33 MPa, and splitting tensile strength of 11.29 MPa with the addition of 1.5% bemban fiber. Although the split tensile strength increases as the fiber content increases, adding 1.5% of bemban fiber is optimum because a higher content decreases the workability of mixtures. [ABSTRACT FROM AUTHOR]