Potential of Orange Peel Ash as a Cement Replacement Material

The potential of Orange peel ash (OPA) as a cement replacement material was investigated with focus on the effect of OPA content on the physicomechnical properties such as consistency, setting times, soundness, compressive and flexural strengths of OPA-cement blend for cement replacement between 2.5-10% at 2.5% interval. The optimal calcination temperature and time of orange peel (OP) was achieved by calcining the OP at various temperature between (600 °C, 700 °C, 800 °C) and time (1 hr. and 2 hrs.) respectively. The chemical compositions of the various orange peel ashes were determined using X-ray fluorescence equipment and the optimal conditions was obtained at 600 °C and 2 hours. The consistency and setting time tests were conducted with a Vicat apparatus on the binary cement pastes in accordance to ASTM standards. Results indicated an increase in the water required for consistency as the OPA content was increased from 2.5-10 % which was attributed to the unburnt carbon content present in the ash. Similarly, a gradual increase in the cement replacement with OPA resulted in a prolonged setting time which was could be attributed to the diminution of the clinker content and the higher water requirement for normal consistence. The soundness of the OPA cement blend experienced an increase in free lime content as the OPA content rose from 2.5-10 %. Both compressive and flexural strengths were found to decrease as the OPA content was gradually increased whereas an increase in the strengths were observed as the curing days progressed. It was also observed that 5% cement replacement with OPA did not adversely affect the strength in comparison to the OPC control due to the pozzolanic reaction which resulted in the enhanced strengths especially at 28 days

Strength Prediction and Optimisation of Velvet Tamarind Pod Ash Cement Blends via Response Surface Methodology

This paper tries to provide a predictive model for determining the mortar compressive strength of Portland limestone cement blended with Velvet Tamarind Pod ash (VTPA) and eggshell powder (ESP). The mortar compressive strength of VTPA-ESP cement blends was determined according to experimental runs from Design Expert 13 using response surface methodology via Central Composite and Box-Benkhen designs, respectively. The factors considered include a blending ratio of 0.25–0.75, cement replacement of 2–6 wt.%, and curing age of 3 and 60 days, respectively. Model equations obtained using response surface methodology via CCD adequately predicted the mortar compressive strength for VTPA-ESP cement blends. The design comparison indicated that CCD produced a better prediction of the mortar strength of the ternary cement blends, which satisfied second-order polynomial regression. When researchers held the curing age and blending ratio constant and increased the cement replacement from 2 to 6 wt.%, they observed a slight increase in the mortar strength followed by a decrease. A similar trend was observed at various blending ratios as the curing age progressed from 3-60 days while the cement replacement and blending ratio was held constant, increasing the mortar strengths. When researchers held the curing age and cement replacement constant, they observed increased blending ratios. Results revealed that despite the diminution of the cement with either VTPA or ESP, the strength experienced either similar or better values than control, proving that pozzolanic activity was experienced. The mortar strength prediction was significantly influenced by the curing age for both CCD and BBD, with high F values for the curing age of 246.23 and 49.62, respectively. Researchers obtained the optimal conditions for predicting the mortar strength of VTPA-ESP-cement blends: blending ratio of 0.258, cement replacement of 3.20 wt.% and curing age of 59.23 days with a mortar strength of 44.93 N/mm2 and desirability of 1.000 for CCD while the blending ratio of 0.283, cement replacement of 2.083 wt.%, curing age of 59.513 days and mortar compressive strength of 45.330 N/mm2 and desirability of 1.000 BBD respectively

Effect of Locust Bean Pod Ash and Eggshell Ash on the Mortar Compressive and Flexural Strengths of Cement Blends

An increase in the generation of biogenic wastes such as locust bean pods and eggshells coupled with the need to drive sustainability in the cement industry has led the use of these wastes as cement replacement materials. The paper aims to investigate the effect of locust bean pod ash (LBPA) and eggshell ash (ESA) on the mortar compressive and flexural strength of ternary cement blends. The LBPA was obtained by calcining locust bean pod (LBP) at various temperatures of 800-900 °C and time of 60–120 minutes at an interval of 50 °C and 30 minutes respectively to determine the optimal conditions. The chemical composition of Ordinary Portland cement (OPC), LBPA and ESA were obtained via X-ray Fluorescence (XRF) Spectrometer and LBPA chemical composition did not satisfy one of the requirements specified by ASTM C618-01 (2001) with SiO2+ Al2O3+Fe2O3 of 30.42 wt. % which is less than 50 wt. %, but satisfies SO3 content requirement of 0.7 wt. % and Loss on Ignition (LOI) of 7.12 wt. % and contains 19.42 wt. % CaO which is within the range of 10-30 wt. % CaO is class C pozzolan. The compressive strength of blended cement mortars at the early age of 2 and 7 days produced better strengths for cement blends with higher ESA content than LBPA especially at LBPA/LBPA-ESA ratio of 0, 0.4 and 0.6 for 2.5 wt. % cement replacement respectively. The early strength gain could be attributed to the provision of more nucleation sites by ESA inclusion which results in the acceleration of cement hydration rate. On the other hand, the enhanced strengths at 28 days of cement blended with various replacement from 2.5–10 wt. % could be attributed to the pozzolanic reaction between the available lime and reactive silica from LBPA despite clinker diminution which was close to control. Another reason for enhanced strength' could be attributed to the increased potassium content by an increase in LBPA content resulting in a gradual strength gain (retarder) muscovite formation K2Al2Si6Al4O20(OH)4. All cement blends experienced an increase in the mortar compressive and flexural strengths as the curing day progressed with some blends producing enhanced strength compared to control especially with 1.5 ESA1LBPA produced the best strength at 50.15 (6.82) N/mm2 against 48.80 (6.80) N/mm2. This enhanced strength could be related to the pozzolanic activity and the high potassium content from LBPA despite clinker diminution, especially at 28 days

Prediction of Loss on Ignition of Ternary Cement Containing Coal Bottom Ash and Limestone Using Central Composite Design

The effect of CBA/CBA-L ratio and the cement replacement on the Loss on ignition (LOI) of ternary cement blends was investigated using central composite design approach in the prediction of LOI of ternary cement blend comprising of Ordinary Portland cement, coal bottom ash and Limestone. LOI is an essential technique employed in the determination of the quality of the cement blend which can be achieved by heating a sample strongly at a specified temperature to enable release of volatile components until the weight remains constant. In this study, monitoring of the LOI of the various cement blends conducted dependent on cement replacement and coal bottom ash to coal bottom ash-limestone ratio (CBA/CBA-L ratio) via thermogravimetric analysis (TGA) and X-ray fluorescence (XRF) analysis. The CBA/CBA-L ratio was varied from 0.25-0.75 while the cement replacement ranges from 20-40%. The significance of these factors within the specified ranges considered was evaluated using analysis of variance.The aim of the study was to evaluate the effect of CBA/CBA-L ratio and cement replacement in the prediction of LOI for ternary cement blends by employing Face Central Composite Design. Analysis of variance results indicated that the LOI prediction via XRF analysis was better than that of TG analyses in which both satisfied Two-Level Factorial model. It was observed from the predictive models that the LOI of the ternary cement decreased as the CBA/CBA-L ratio was increased while LOI of the ternary cement blend increased as the cement replacement was increased. An increase in both CBA/CBA-L ratio and cement replacement resulted in a decrease in the LOI of ternary cement. The cement replacement level of the ternary cement blends indicated a stronger influence on LOI compared to the CBA/CBA-L ratio which was indicated by a significantly high F value for cement replacement compared to CBA/CBA-L ratio.The LOI results from XRF analysis were also found to significantly predict the LOI of the ternary cement blend compared to TGA with Regression value of 99.96% against 97.36% respectively. The CBA/CBA-L ratio and cement replacement were found to have a significant and interactive effect on the LOI of ternary cement blend for both XRF and TGA analyses

Prediction and Optimization of Sulphur Trioxide Yield from Calcination of Aluminium Sulfate Using Central Composite Design

Sulphur trioxides are common toxic gaseous pollutants which can be produced from alternative routes via calcination of aluminum sulfate derived from kaolin clay. Its demand increases geometrically, thus the need to optimize the yield of SO3 from the calcination of alum is essential. The rate of alum decomposition was monitored by the formation of SO3 via thermogravimetric analysis and X-ray fluorescence analysis. This study aimed to evaluate the effect of calcination temperature and curing time on the SO3 conversion and yields using Face Central Composite Design and optimize the process conditions to evaluate the maximum yield of SO3 using response surface methodology and its effects and interactions were investigated between 800–900 °C at 60-180 minutes. Results indicated that experimental data satisfied second order polynomial regression model for SO3 conversion and SO3 yield from TG analysis while XRF analysis satisfied first order model respectively. An increase in SO3 conversion and yields was observed as the calcination temperature and time were increased both independently and simultaneously. The calcination temperature was found to have a stronger influence compared to the calcination time. Validation indicated agreement between experimental and predicted values with a regression value of 97.8 %, 97.77 % and 97.67 % for SO3 conversion, SO3 yield via TG and XRF analyses respectively. Based on the ANOVA, the SO3 yield via XRF produced the best model with R2pred of 91.98% while SO3 yield via TG analysis and SO3 conversion had R2pred of 79.99% and 78.01% respectively. Optimization of the production of SO3 was carried out and the optimal condition for SO3 conversion, SO3 yield via TG and XRF analyes were 90.11 %, 91.67 % and 75.81 % respectively at an optimal calcination temperature of 877.43 oC and time of 155.04 minutes respectively

Investigation of the Potentials of the Binding Properties of Mango, Cashew and Blended Gums

This research is aimed at production and investigation of the potentials of blending mango gum with cashew gum on its binding properties as a substitute for gum Arabic. The high demand for adhesives has led to the search for other alternatives to Arabic and cashew gum due to their high cost and non-availability. Thus, the need to investigate the potentials of mango gum as well as the possibility of replacing mango gum with cashew gum to be employed as an adhesive. The raw gum was extracted from the mango tree, dried, sorted, underwent size reduction of the gum exudates, sieved into different mesh sizes, dissolved in distilled water and centrifuged to remove impurities and other polysaccharides. The binding properties of the extracted mango gum was monitored in terms of physicochemical properties such as viscosity, pH and specific gravity of the gum using capillary viscometer, pH meter and density bottle respectively. The variation of the agitation speed between 250, 500 and 750 rpm, particle size of the raw MG between 75 µm, 212 µm and 300 µm and the replacement of MG with CG from 0-50% at interval of 10% respectively. The effect of agitation speed, particle size of the raw MG and the replacement of MG with CG were investigated in terms of the viscosity, pH and specific gravity of the gum and found that the best quality gum was obtained at particle size of 75 µm, pH of 4.7, agitation speed of 500 rpm and specific gravity of 1.06 respectively. Results indicated that the use of additives such as glycerine, starch and zinc oxide enhanced the binding properties of the gum and MG as well as gums blended with CG were found to fall within the limits to be considered to possess good binding properties. An increase in MG replacement with CG up to 50 %, resulted in a decrease in viscosity and specific gravity of the blended gum by 21.32 % and 3.77 % respectively while pH experienced an increase from 4.4-5.7 i.e. more alkaline in nature

A Study on Ordinary Portland Cement Blended with Rice Husk Ash and Metakaolin

Abstract. This paper tries to investigate the effect of replacing Ordinary Portland cement (OPC) with Metakaolin (MK) and Rice husk ash (RHA) on the physicomechanical properties such as consistency, setting times, soundness and mortar compressive strength of ternary cement up to 40 % cement replacement. The soundness of the blended cement pastes and compressive strength of the blended mortars were conducted using Le Chatelier apparatus and Tonic Technic compression machine while the initial and final setting times were conducted on the blended cement paste using Vicat apparatus. Nineteen ternary cement mortars were prepared to comprise of OPC, RHA MK at different proportions and tested at 2, 7, 28 and 60 days. Results indicated that as RHA was gradually increased up to 25% at constant MK content, the volume expansion of the ternary cement paste increased gradually. On the other hand, as MK was increased from 5-25% at constant RHA, the volume expansion diminished. The water consistency of ternary cement paste experienced a variation as MK was increased up to 25 wt% at constant RHA up to 10 wt%. However, at 10 wt% constant RHA as MK was increased the water demand gradually increased. Similarly, an increase in RHA at constant MK increased the water demands of the ternary blends. An increase in RHA from 5-25 wt% at 5-25 wt% constant MK resulted in an acceleration in the initial and final setting times of cement blends. These accelerations could be attributed to the pozzolanic activity leading in shorter setting time. Whereas a series of accelerations and retardations of both setting times were experienced as the MK was increased from 5-25 wt% at 5-25 wt% constant RHA. It was observed that increment in the MK or RHA up to 10 wt% at constant RHA/MK up to 10 wt% resulted in improved mortar compressive strength of the ternary blend in comparison with control. This improvement was attributed to the high silica/alumina contribution to the matrix by MK inclusion, the C/S ratio in the cement matrix and RHA pozzolanic reactivity despite its unburnt carbon. All mortar compressive strength of the cement blends and control experienced an increase as the curing days were lengthened from 2 to 60 days. The enhanced strength compared with the control especially beyond 28 days could be attributed to the slow pozzolanic reaction resulting from the formation of additional CSH and CAH from the interaction of the residual CH and the silica available in the MK and RHA. The best compressive strength at 60 days was obtained at cement replaced with 15 wt% and 20 wt% at MK 5 wt% RHA producing a mortar compressive strength of 40.5 MPa

Biogas and Biofertilizer From Waste: A Review

Bio-resources, particularly non-fossil biogenic materials, offer sustainable energy production, waste management, and soil enrichment solutions. Biogas technology, leveraging anaerobic digestion (AD), transforms diverse organic wastes into methane, an eco-friendly energy source. This review highlights the potential of bio-fertilizer and biogas production from various waste types, including animal, plant, sewage sludge, and agricultural residues. Animal waste, mainly cow dung and poultry droppings, is an effective substrate for biogas production, with co-digestion methods enhancing yield and efficiency. It also revealed that blending poultry droppings with banana peels or cow manure with delignified spent coffee grounds optimizes the carbon-to-nitrogen ratio, improving biogas and bio-fertilizer yields. Plant waste, such as water hyacinth and Ulva sp. seaweed, also shows promise when co-digested with animal waste. The review further noted that adding biochar to plant waste significantly enhances biogas production and improves the nutritional value of spent slurry, making it suitable as a bio-fertilizer. Chemical pretreatments of agricultural residues like wheat straw further ensured increased biogas yield and improved the biomethane production kinetic. This review observed that sewage sludge from wastewater treatment plants significantly boosts biogas production, particularly when co-digested with food waste. Adjusting optimal mixing ratios and mechanical mixing techniques enhanced biogas yield and energy potential, while the resulting digestate meets regulatory standards for use as a soil conditioner. This review underscores the economic and environmental benefits of optimizing biogas and bio-fertilizer production, particularly in regions like Nigeria, where such practices can address challenges in electricity generation, fertilizer costs, and waste management

Effect Of Quartz Particle Size and Cement Replacement on Portland Limestone Cement properties

This research focuses on investigating the effect of quartz particle sizeand cement replacement on their physicomechnical properties. Portlandlimestone cement (PLC) was employed and replaced with quartz powder(QP) at various particle sizes (1.19 mm, 425 µm, 300 µm, 212 µm, <212µm) and cement replacement between 2.5 wt.% ~ 15 wt.% at interval of2.5 wt.% to study their impact on the cement properties. The PLC chemical composition revealed a relatively low lime and high silica contentcompared to the conventional cement. QP revealed a high silica, lime andsulphur contents compared to natural sand. A high consistence, elongatedsetting times and lower strengths and specific gravities were observed ascement was replaced with QP at a given particle size respectively. Theeffect of replacing cement with QP content between 2.5 wt.% and 15 wt.%at various particle sizes resulted in average increments by 45.32%, 23.13%and 36.06% for initial setting time, final setting time and water demandrespectively. This increase could be related with clinker diminution coupled with enhanced QP surface area and clinker diminution. Similarly, anincrease in the QP surface area at a given cement replacement led to higherwater consistence, retarded setting times and lower strength. The effect ofenhancing the QP’ surface area between 1.19 mm and below 212 µm at agiven cement replacement resulted in average increments by 26.27%, 8.61%and 7.49% for initial and final setting times and water demand respectively.The strength gain of the QP cement blend diminished significantly above30% up to 15 wt.% cement replacement especially beyond 3 days. The lowstrength could be due to the high-water consistence linked with silica content resulting in setting time retardation. The optimal QP content was determined at 5 wt.% owing to the fact that the physicomechnical properties didnot significantly deviate from the properties of control