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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]

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]