Feasibility assessment for partial replacement of fine aggregate to attain cleaner production perspective in concrete: A review

Properties of concrete containing recycled seashells as cement partial replacement: A review

Carbon dioxide emissions from cement production have a significant impact on the environment. The huge energy consumption in the cement production process is also a problem. Pakistan is responding to a severe energy crisis. The price of cement is growing day by day. In addition, the use of waste for the disposal and recovery of natural concrete components can cause environmental degradation. Using waste not only reduces cement production, thereby lowering energy consumption, but also helps to protect the atmosphere. The aim of this research is to study the properties of concrete using silica fume as a partial replacement of cement and glass waste instead of fine aggregate. This research includes the study of workability, water absorption, compressive strength and split tensile strength. In this experimental study, 5%, 10% and 15% by weight of cement were replaced with silica fume, and fine aggregates were replaced with 10%, 20%, 30 and 40% by waste glass powder. A total of 20 mixtures in which one control mix, three mixes with addition of silica fume, four mixes with incorporating of glass powder and twelve mixtures with combined use glass powder and silica fume were prepared with 1:2:4 mix ratio at 0.5 water-binder ratios. According to the study parameters, replacing 10% cement with SF and 30% fine aggregate with glass powder is the best choice for optimum strength. Moreover, the utilization of glass powder and silica fume together significantly reduces the workability and water absorption of the composite concrete mixture.

Effect of Silica Fume as Cementitious Material and Waste Glass as Fine Aggregate Replacement Constituent on Selected Properties of Concrete

Palm Kernel Shell (PKS) is an economically and environmentally sustainable raw material for renewable energy industry. To this vane its physicochemical properties were determined for its most viable application in Renewable Energy options such as bioenergy and biomass utilization. Its higher heating values determined by bomb calorimetric method are 22.94 and 25.27MJ/kg on dry and dry ash free bases respectively while its thermo-gravimetric behavior shows that it can completely decompose between 400°C and 500°C. Its compositional analysis by 72% sulphuric acid hydrolysis and High Pressure Liquid Chromatography (HPLC) analysis of structural carbohydrates show that its lignin, cellulose and hemicellulose compositions are respectively 50%, 7% and 26%. Under high resolution scan electron microscope, (SEM), PKS contains natural micro pores that enable it release volatile matter necessary for bio-energy production. The results of the ultimate analysis show that the raw material contains high carbon and moderate h ydrogen content. These are responsible for the large value of its higher heating value. These results show that PKS possess valuable potential to supplement the energy supply of developing countries through sustainable renewable energy technologies. Keywords: palm kernel shell, bioenergy, thermogravimetric analysis, pyrolysis, gasification

https://www.ajol.info/index.php/njt/article/download/83796/73804

Determination of Bio-energy Potential of Palm Kernel Shell by Physicochemical Characterization

This research offered that the rice husk ash is served as replacement for cement ingredient such as 5%, 10% and 15% along with 10%, 20%, 30% and 40% of fine aggregates replaced with coal bottom ash in concrete. In this regard, total 180 concrete samples were prepared with mix proportion of 1:2:4 at 0.50 water/cement ratio and theses specimens were cured at 28 days. However, the main theme of this study is to perform the slump test, compressive strength, split tensile strength and water absorption of concrete including different proportions of rice husk ash as replacement for cement and fine aggregates replaced with coal bottom ash separate and combine. The outcome was detected that the workability and water absorption is dropped as the dosages of rice husk ash and coal bottom ash increases in concrete. Moreover, the compressive and split tensile strength is enhanced by 9.10% and 7.73% while the utilizing of 5% RHA along with 30% of fine aggregate replaced with coal bottom ash in concrete at 28 days consistently.

An Investigation on Fresh and Hardened Properties of Concrete Blended with Rice Husk Ash as Cementitious Ingredient and Coal Bottom Ash as Sand Replacement Material

An exploratory study of crushed periwinkle shell (CPWS) as partial replacement for fine aggregate in concrete was carried out. Mechanical and Physical properties of the (CPWS) and fine aggregate (river sand) were determined and compared. Concrete cubes of 1:2:4 and 1:3:6 by weight of cement, were prepared in the laboratory, using the following proportions, 0:100, 30:70, 50:50 and 100:0 CPWS to fine aggregate (river sand). 14, 21 and 28 days compressive strength test were carried out on the concrete cube. The CPWS had an average moisture content of approximately 11.65%, the highest amongst the aggregates. Physical examination of the CPWS particles showed that the grains were angular in shape with rough surface texture. The sieve analysis test revealed that the particle sizes were fine aggregates with about 98.8% passing through the British sieve No. 4 (4.75mm). The CPWS had a bulk density of 1504kg/m3, while that of the river sand was 1636kg/m3. The workability test revealed that the slump values decreased in the concrete mixture as the quantity of CPWS increased. It was also discovered that the compressive strength decreased with increased percentage of replacement of the river sand with CPWS. The control (highest) 28 days compressive strength of the concrete produced with zero percent CPWS and 100% river sand was 24.89N/mm2. 28 days compressive strength of concrete cubes with 50% CPWS and 50% river sand for mix proportion of 1:2:4 was 18.00N/mm2. From the results of this exploratory study, it can be safely concluded that CPWS can be used as a partial replacement of river sand in the production of light weight concrete in areas where the periwinkle shells are in abundance. The purpose of the study is to explore the possibility of turning waste to wealth. A significant factor is that concrete will be produced cheaper in areas with large population of periwinkle shells, while the environment that these periwinkle shells are usually dumped will become better protected.

Exploratory Study of Crushed Periwinkle Shell as Partial Replacement for Fine Aggregates in Concrete

This study investigated the impact of palm bunch ash (PBA) on the stabilization of poor lateritic soil. The palm bunch ash in percentages by weight (0%, 20%, 25% and 30%) was added to the lateritic soil. The 0% PBA acted as the control. The following parameters of the (lateritic soil+ palm bunch ash) were tested in the laboratory: Maximum Dry Density (MDD), Optimum Moisture Content (OMC), California Bearing Ratio (CBR) and unconfined compression strength (UCS). The values of the MDD, OMC, CBR and UCS increased as the PBA content in the lateritic soil was increased up to between 25% PBA, thereafter the values started to decrease. The UCS of the (lateritic soil + palm bunch ash) specimen cured for 14 days were also found to higher than that of 28 days curing period at 20% PBA content. The UCS values for 14 days became higher than that at 28 days at 25% PBA content. The PBA can be used as a lateritic soil stabilizer between (20-25%) PBA content. Keywords : palm bunch ash, lateritic soil, California Bearing Ratio, Optimum Moisture Content, Maximum Dry Density.

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Investigation of the impact of palm bunch ash on the stabilization of poor lateritic soil

Aggregate, both fine and coarse are major components of concrete. The cost of these aggregates is on the increase. There is also a serious environmental concern for the disposal of waste glass world-wide. These factors are major thrusts of this study- the investigation of crushed waste glass as partial replacement of fine aggregate in concrete, with a view to protecting the environment and also reducing the cost of concrete. The study investigated the level of replacement of fine aggregate with waste glass that will result in optimal compressive strength. A total of 36 cubes were cast. 6 cubes without waste glass (control) and 30 cubes containing waste glass as partial replacement for fine aggregates at 15%, 25%, 35%, 45%, and 50%. Water/cement ratio of 0.6 was used. The concrete cube samples were cured and tested at 7 and 28 days respectively for compressive and flexural strength, water absorption and light weight character. Compressive strength were found to increase by 3% and 7% at 7 and 28 days respectively as waste glass content was increased up to 15% replacement level, after which the compressive strength started to decrease. Flexural strength remained constant between the control value and 15% replacement level, after which it started to fluctuate, (decreasing by 25% and 47% at 25% replacement level at 7 and 28 days, and experienced an increase of 33% and 37.5% at 35% at replacement level. Water absorption of the concrete decreased as the waste glass content increased. Initial and final setting times decreased as the waste glass content increased, while the workability of the concrete increased as the waste glass content increased and started to experience a decrease at 35% waste glass replacement level. Key Words : compressive strength, concrete, crushed waste glass, flexural strength, setting time, water absorption and workability.

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Performance of concrete with partial replacement of fine aggregates with crushed waste glass

The effect of sugar cane juice, (SCJ) on slump values, setting time and compressive strength of concrete cubes was investigated. A total of 32 concrete cubes of size 150x150x150mm with a mix ratio of 1:2:4 were cast with different percentages of unfermented sugar cane juice replacing some proportion of water in the concrete mix. Water/Sugar Cane Juice/cement ratio was held constant at 0.45. The concrete cubes were prepared by replacing water with SCJ in the following proportions 0, 25, 50 and 100%. The cubes were cured, tested and the physical properties of interest in this study were determined. The slump values of the concrete decreased from 40mm at 100: 0 (water:SCJ) to 18mm at 50:50 (water:SCJ) and to 0mm (collapse) at (0:100) (water :SCJ). The final setting time of concrete increased with increase in proportion of SCJ. The highest final setting time of 42 hours (considered excessive), occurred at 75:25 (water:SCJ) proportion. The compressive strength of the (water:SCJ) concrete decreased as the percentage of SCJ increased up to 25% SCJ. Thereafter, an increase in compressive strength was noticed up till 100% SCJ, with a maximum strength of 13.08N/mm 2 occurring at 100% SCJ at 28 days. The early strength reduction is due to quick-setting of the concrete, at 25% SCJ, retardation commences and the strength of concrete increases. The study has been carried out at 0, 25, 50 and 100% replacement by weight of potable water with SCJ. A comparative study has been done between concrete made with potable water and those made with water/sugar cane juice. http://dx.doi.org/10.4314/njt.v34i2.6

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Effect of sugar cane juice on slump values, setting times and strength of concrete

The research was targeted at finding out if crude oil polluted soils in the Niger Delta Area of Nigeria will still retain their original values of geotechnical properties. If not, establish, the effect of crude oil pollution on the geotechnical properties of the crude oil polluted soils and determine the shear strength of the affected soils. This was achieved by carrying out soil investigations at randomly selected crude oil polluted sites and also carrying out another set of soil investigations at nearby locations which enabled the geotechnical properties of the crude oil polluted soils to be compared with those of unpolluted soils. Evaluation of the effects of crude oil pollution on the engineering properties of the affected soils and comparison with the engineering properties of unpolluted soils of similar soil structure within the same zone was carried out. Decrease in values of un-drained cohesion, un-drained angle of internal friction, optimum moisture content, maximum dry density, coefficient of consolidation, coefficient of permeability of the polluted soils were established from the study. The mathematical interrelationship (Mohr-Coulomb equation) between these soil properties and shear strength and soils was used to establish the reduction in shear strength of polluted soils.

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AW Otunyo

Papers

Exploratory Study of Crushed Periwinkle Shell as Partial Replacement for Fine Aggregates in Concrete

Investigation of the impact of palm bunch ash on the stabilization of poor lateritic soil

Performance of concrete with partial replacement of fine aggregates with crushed waste glass

Effect of sugar cane juice on slump values, setting times and strength of concrete

Reduction of the Shear Strength of Soils in the Niger Delta Area of Nigeria Due to Crude Oil Production