Global production of palm oil in 2022 was estimated at 73 million metric tonnes. The processing of palm oil generates a huge quantity of waste which is often left unprocessed leading to environmental pollution. Gravels are obtained from weathered rocks and are readily available and cheaper than granite as coarse aggregate in concrete. An innovative way of transforming waste into wealth is by incorporating these materials into concrete for construction purposes. Thus, this study was done to obtain an ideal combination of gravel and granite in palm oil fuel ash (POFA)-blended concrete. A water/cement (w/c) ratio of 0.5 in a nominal concrete mix ratio of 1:2:4 was adopted to achieve a strength of 20 N/mm 2 . The central composite method of optimization was utilized in designing the experiments. The best combination was determined to be 67% gravel, 33% granite and 32% POFA. This combination produced concrete with compressive strength of 23.80 N/mm 2 which is 19% higher than the 20 N/mm 2 target strength.

The menace of wastewater pollution in the 21st century is becoming alarming. Application of the low-cost adsorbents for wastewater treatment has received more attention this moment in environmental history than never. Most industrial wastewater has not been receiving adequate treatment prior to disposal into the nearby stream, and this is a potential threat to plants and animals feeding therefrom. There is therefore the need to proffer an effective solution to this pollution problem. An approach of bioremediation with a cost-effective plant waste is considered apt, with the application of Azadirachta indica (Neem tree) bark as adsorbent in this study. Galvanizing/wire-gauze industrial wastewater effluents were collected and subjected to Atomic Absorption Spectrophotometry (AAS) analysis to determine the concentrations of heavy metals. Phytochemical and Proximate analyses of the adsorbent were performed while adsorption study with the effects of adsorbent dosage, contact time, stirring speed and pH on the adsorption process during the wastewater treatment was carried out. The adsorption isotherms and kinetic models that best described the adsorption of Pb 4+ and Cr 3+ were established.

This research investigated the effects of aluminium shavings on particleboards produced from sawdust and waste glass using Urea formaldehyde as binder. Twelve (12) boards were produced and each had different variations of sawdust, waste glass and aluminium shavings with a constant volume of adhesive used. The boards were tested for physical properties such as density, Thickness swelling (TS) and Water absorption (WA) and mechanical properties such as modulus of rupture (MOR) and modulus of elasticity (MOE). The effects of the aluminium shavings on the boards were observed in the MOR and MOE values such that these values for board A1 were 3.30 N/mm2 and 10.45 N/mm2 for 20% aluminium shavings content but reduced to 3.16 N/mm2 and 8.97 N/mm2 respectively for board A2 with 10% aluminium shavings content. This trait was observed in other boards with the same content except in boards B1 and B2 where the MOR and MOE values increased with the values for B1 being 2.06 N/mm2 and 6.98 N/mm2 and 2.91 N/mm2 and 10.17 N/mm2 respectively. The values for density of the boards increased as the sawdust decreased and also as the glass content increased. The boards with the highest values for thickness swelling and water absorption were the first three as they possess the highest quantity of sawdust. From the results, none of the boards produced met up to the requirements for use for structural purposes, board B3 possesses the highest MOR value while board D3 possesses the highest MOE value. Therefore, the boards can serve non-structural purposes such as partitions and indoor uses.

Natural river sand is one of the important constituent materials in concrete production while stone dust is a material obtained from crusher plants which is also sometimes being used either partially or fully in replacement of natural river sand in concrete production. Use of stone dust in concrete not only improves the quality of concrete but also conserve the natural river sand. However, due its scarcity and environmental degradation caused resulting from excessive mining of Natural river sand, there is need to investigate an alternative material of the same quality which can replace river sand in concrete production. In the present study, experiments were carried out to study the gradation of aggregates, workability, compressive strength and split tensile strength of concrete made using quarry dust as replacement of fine aggregate at 0, 25, 50, 75, and 100%. Grade M15 of concrete was produced with ordinary Portland cement (OPC) for referral concrete while M25 of concrete was prepared for compressive strength and split tensile strength concrete. Workability and Compressive strength were determined at different replacement level of fine aggregate and optimum replacement level was determined based on compressive strength. Results showed that by replacing 50% of fine aggregate with quarry dust, concrete of maximum compressive strength can be produced as compared to all other replacement levels. The effect of quarry dust on compressive strength and split tensile strength was investigated and from the overall result obtained, it was observed that the compressive strength and split tensile strength increased significantly for all the curing ages from 0% to 50% replacement level of quarry dust. Maximum value obtained for 28day compressive and tensile strength were 25N/mm2 and 2.3N/mm2 respectively and this occurred at 50% replacement.

This study considers the utilization of bitumen modified with polyethylene terephthalate (PET) bottles waste as an alternative binder in paving blocks. The optimum bitumen content of asphalt concrete was modified with 2%, 4%, 6%, 8%, and 10% of PET waste. The compressive strength test, skid resistance, water absorption, and abrasion test were conducted on the paving block samples. Compressive strength test was conducted to verify the samples' compressive strength performance while water absorption and abrasion test were used to ascertain the durability properties of the samples. Results obtained for PET-modified bitumen concrete paving blocks (PMBCB) show an increase in compressive strength, skid resistance, and a decrease in the water absorption and abrasion loss when compared to unmodified bitumen samples. The maximum compressive strength for the PET-modified bitumen concrete was recorded at 10% PET replacement level. This implies that the utilization of PET-modified bitumen as binders in concrete paving blocks will not only help in waste recycling but also contribute significantly to the protection and preservation of the environment.