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Test production and evaluation of cement-based composite water delivery pipe

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https://www.eduzhai.net International Journal of Composite Materials 2016, 6(1): 9-14 DOI: 10.5923/j.cmaterials.20160601.02 Experimental Production and Evaluation of Cement-Bonded Composite Pipes for Water Conveyance S. A. Nta, A. O. Olorunnisola* Department of Agricultural and Environmental Engineering, University of Ibadan, Nigeria Abstract Cement-bonded particleboard was investigated for its potentials as a conduit pipe material. As a cost reduction strategy, the effects of partial replacement of Portland cement with ground eggshell powder and waste carbide on the properties of the composite pipes were also investigated. 300 mm long pipe specimens were manufactured in two thicknesses of 6mm and 8mm, each one having an outer diameter of 166mm. Selected physic-mechanical properties of the pipes were assessed using standard methods. Results obtained showed that the density (<500 Kg/m3), water absorption (< 40%) and thickness swelling (<6%) of the pipes were generally within acceptable limits. The burst strength (0.02- 0.10 MPa) was relatively low compared to values reported in literature for polyvinyl chloride (0.875 – 1.79 MPa), asbestos (0.86 – 1.38 MPa) and aluminum (1.38 and 3.24 MPa) pipes. The values also decreased with increase in proportions of eggshell and carbide waste. The eggshell appeared to have more negative effect on the pipe properties than carbide waste. The pH of the water samples deliberately stored in the pipes for 24 hours at room temperature ranged between 8.0 and 10.7. These findings, particularly the relatively low burst strength, suggest that the composite pipes would better be put to use in activities that do not require high pressure water conveyance. Keywords Composite pipes, Sorption properties, Burst strength, Eggshell, Carbide waste 1. Introduction Piping is an important aspect of water conveyance. The most common water piping materials include aluminum, asbestos, steel, and plastic pipes from polyvinyl chloride and high density polyethylene [1], while those for drainage include concrete, clay, corrugated and plain plastic [2]. However, asbestos pipes that were common in the past have now being discredited due to the negative image asbestos has acquired in recent times. One of the materials that has replaced asbestos in the building industry but is yet to be explored for its potentials as a conduit pipe material is cement-bonded particleboard. Cement-bonded particleboards are low-cost composite materials produced from a mixture of cement, water, and particles obtained from wood and other lingo-cellulosic materials to provide a wide range of products for structural and nonstructural applications. In addition to their fire resistance, these materials have a special attraction for use in warm, humid climate where termites and decay are a major concern. Further benefits include easy machining with conventional wood-working tools and simple fabrication. The cement binder provides a durable surface as well as one * Corresponding author: abelolorunnisola@yahoo.com (A. O. Olorunnisola) Published online at https://www.eduzhai.net Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved that can be easily embossed and colored for an attractive, low-maintenance finished product [3]. However, cement production is known to contribute to the greenhouse effect due to the emission of CO2 gas during the clinker manufacturing process [4]. Mehta [5] proposed ways for reducing the CO2 emissions of the cement industry which include consuming less concrete, consuming less cement in concrete mixtures, and consuming less clinker in cement. Calcium carbide waste, a by-product from an acetylene gas welding process is largely made up of calcium hydroxide (Ca(OH)2) in slurry form. Most of the residue is sent to landfills as waste causing environment problems, including groundwater pollution due to alkaline contamination. The problem of carbide disposal has a long history. Semikolennykh et al. [6] reported that spent carbide is toxic for biota, with calcium hydroxide being one of the toxic components. They also recommended that spent carbide deactivation could be provided within isolated bowls filled with water (micro sediment bowls) or within water-proof storage containers, while complete recycling could be achieved through the addition of the deactivated waste to solid building materials such as cement that are meant to solidify and thus bound toxic compounds and exclude their dissolution. Another material that could be used as partial replacement for cement is chicken eggshell which contains about 95% calcium carbonate in the form of calcite and 5% organic materials such as type X collagen, sulfated polysaccharides, 10 S. A. Nta et al.: Experimental Production and Evaluation of Cement-Bonded Composite Pipes for Water Conveyance and other proteins [7, 8]. In the U.S. alone, about 150,000 tons of this material is disposed in landfills [7]. Its chemical composition and ready availability qualify eggshell to be used as a potential source of filler in the production of cement-bonded composite pipes. The specific objectives of this study were to (i) produce cement-bonded composite pipes using carbide wastes and eggshell powder as partial replacements of ordinary Portland cement, and (ii) determine selected engineering properties of the pipes. The inner moulds were removed immediately after its production while the outer diameter covering were removed after 24 hours and the resulting samples (produced in triplicates for the different experimental variables) were cured in the open air at room temperature for 28 days. 2. Materials and Methods Ordinary Portland cement was procured from the local market in Ibadan, Oyo State. It was stored in air tight nylon bag and was used up soon after delivery to prevent strength deterioration. Sawdust generated from Teak (Tectona grandis) wood was collected from a Sawmill at Sango, Ibadan, Nigeria. The species was selected due to it availability and relatively high strength. The sawdust was sieved. Particle that passed through 850µm sieved and were retained on 600 µm sieve soaked in potable water at room temperature (average of 27.8°C) for 24 hours to reduce the amount of water-soluble sugars and tannins that could inhibit the setting of cement and air-dried. The oven dry moisture content was determined as 5.29%. Calcium carbide waste was collected from a mechanical workshop, sun-dried for 4-5 days to reduce the moisture content, and ground in a burr mill until the particles passed through a 212µm sieve. Its oven-dry moisture content was also determined as 2.5%. Eggshells were collected from an hatchery at Oluyole Industrial Estate, Ibadan Nigeria, washed with water, sun dried and ground in a burr mill. Particles that passed through a sieve size of 212µm were used. The oven dry moisture content the ground eggshell was determined as 0.88%. Medium size sand particles of about 2mm in size were collected from a river in the University of Ibadan campus. The sand was washed, air-dried and sieved to remove the dirt and big stones using mechanical shaker. The sand particle that passed through sieve number 500µm was used. Pipe production parameters were: cement: sand ratio 1:3 by volume; cement: sawdust ratio 3:1 by weight (controls); 10, 20, 30% partial replacements of cement with carbide waste, eggshell and a combination of carbide waste and eggshell (50:50) by weight. The materials were weighed accordingly and mixed manually in the dry state until acceptable level of uniformity and even distribution were obtained. Measure quantity of potable water then was slowly added while mixing to achieve uniform consistency. The mixture was then placed in specially fabricated metallic moulds (shown in Figures 1 and 2), and gently compacted. Figure 1. Moulds Specially Fabricated for Pipe Production The samples of length 300mm were weighted using electronic weighing balance and the volumes density were calculated. The oven-dry moisture content was also determined at a temperature of 103 ± 2°C for 24 hours for constant weight. It was expressed as percentage of oven dry weight. The moisture content test was carried out on pipes of length 300 mm cut with a saw blade to a length of 150mm. The same dimensions were used for the water absorption test samples which were weighed. The initial thicknesses of the samples were taken with a digital veneer caliper and mark with a marker at the top at five equal intervals, before they were immersed in water for 24 hour at room temperature Each sample was then withdrawn from water and allowed to drain for 2 minutes before the final weight and thickness were measured and recorded for each specimen. The Water Absorption (WA) was calculated from the increase in weight and expressed as the percentage by dry weight. WA (%) = ????2−????1 × 100 % ????1 Where m2 is the weight (g) of the specimen after soaking and m1 is the weight (g) of the specimen before soaking. The thickness swelling (TS) was calculated using the formula: TS = T2 −T1 × 100 % T1 Where, T1 is the thickness before soaking, and T2 is the thickness after soaking. International Journal of Composite Materials 2016, 6(1): 9-14 11 Density (g/cm3) Figure 2. Burst Strength Testing Rig 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 8mm 6mm Wt % Composition of cement Figure 3. Mean Densities of the Composite Pipes The burst strength test on the pipes was carried out using a testing rig designed and fabricated as reported in [9] and shown in Figure 3. The maximum pressure at which composite pipe of 300 mm length would burst taking note of its thickness and diameter was investigated. The composite pipes were inserted between the two flanges and the four threaded rods were tightened with nuts so as to provide air/and water tight condition for effective testing of the bursting strength. Water was poured into the pipe through gate valve, until the composite pipe was filled up and compressed air was passed into the pipe from a 2 HP air compressor. Burst pressure was monitored on the pressure gauge installed on the supply line of the air compressor. The pH of water samples deliberately stored in the composite pipes closed at one end for 24 hours was measured using Hanna Pocked-sized pH meter calibrated using pH calibration buffer solution. The electrode of the pH meter was dipped into the stored water. 3. Results and Discussion 3.1. Densities of the Composite Pipes Figure 3 shows the mean densities of the composite pipes. Since sawdust, an hygroscopic material, was part of the composite materials used, the moisture contents were also determined as indicated in Figure 4. The density of the pipes decreased with increasing level of partial replacement of cement with carbide waste, eggshell and a combination of carbide waste and eggshell. This is attributable to the bulk densities of the carbide waste and egg eggshell powder. Pipes containing eggshell powered had the lowest density while the control (i.e., pipes made from only cement and sand) recorded the highest density. This is a common observation in wood cement particleboard products since wood particles generally tend to have lower bulk densities than cement. The differences observed in the densities of the 12 S. A. Nta et al.: Experimental Production and Evaluation of Cement-Bonded Composite Pipes for Water Conveyance control and the experimental samples as well as between the 6mm and the 8 mm pipes were significant (???? = 0.05). As would be expected, pipes produced with cement and sawdust alone had the highest moisture content, while the control recorded the lowest moisture content. Also, the moisture content of pipes decreased with increasing partial replacement of cement with eggshell, carbide waste and a combination of carbide waste and eggshell. The differences in moisture content between the control and experimental samples were significant. However, there was no significant difference (???? = 0.05) in the moisture contents of the 6mm and 8mm pipes. Legend: CS – Cement + Sand (Control) CSD – Cement + Sawdust 10E – 10 % Eggshell powder 20E – 20 % Eggshell powder 30E – 30 % Eggshell powder 10C – 10 % Carbide 20C – 20 % Carbide 30C – 30 % Carbide 10CE – 10 % Carbide + Eggshell powder 20CE – 20 % Carbide + Eggshell powder 30CE – 30 % Carbide + Eggshell powder 3.2. Water Absorption Figure 5 shows the mean Water Absorption (WA) of composite pipes. Composite pipes made with partial replacement of cement with eggshell had the highest WA, while the control had the lowest. This suggests that eggshell has more affinity for water than carbide waste. There were no significant difference (???? = 0.05) in the WA of the 6mm and 8mm pipes, but there was significant difference between the controls and the experimental samples. This may be due to uneven distribution of eggshell and carbide waste in the mixture which resulted in the formation of void spaces in the products. Moisture Content (cm3) 12 10 8 6 4 8mm 2 6mm 0 Water Absorption (%) Wt % Composition of Cement Figure 4. Mean Moisture Content of the Composite Pipes 40 35 30 25 20 15 10 5 0 8mm 6mm Wt % Composition of Cement Figure 5. Mean Water Absorption of the Composite Pipes International Journal of Composite Materials 2016, 6(1): 9-14 13 Thickness Swelling (%) 3.3. Thickness Swelling Figure 6 shows the mean Thickness Swelling of composite pipes. The range of TS observed for all the 6mm and 8mm thick pipes (including the control) ranged between 0.30 and 5.3% after 24 hours of submersion in water. The control recorded the lowest while pipes made using eggshell. 6 5 4 3 8mm 2 6mm 1 0 Burst Strength (Bars) Wt % Composition of Cement Figure 6. Mean Thickness Swelling of the Composite Pipes 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 8mm 6mm Wt % Composition of Cement Figure 7. Mean Burst Strength of the Composite Pipes as partial replacement for cement recorded the highest TS. There was no significant difference in TS ( ???? = 0.05) between 6mm and 8mm pipes, but there were significant differences between the control experimental samples. The TS increased with increasing partial replacement of cement with eggshell and carbide waste which suggests that cement coating may have restrained effect on the swelling of composites. 3.4. Burst Strength Figure 7 shows the mean pipe burst strength of the composite pipes. The control samples recorded the highest burst strength (0.14 to 0.2 MPa), while pipes with partial replacement of cement with eggshell recorded the lowest burst strength. The burst strength decreased with increasing partial replacement of cement. This may be mainly attributed to the poor adhesion between the lignocellulosic materials, which did not allow efficient stress transfer between the phases of the materials. The burst strength also appeared to depend on the density of the pipes. 3.5. pH of the Water Stored in the Pipe Table 1 shows the pH of the stored water samples after 24 hours of pipe immersion. pH is one of the indicator of water quality for irrigation. The pH values were generally in the alkaline range which was higher than the range for irrigation. 14 S. A. Nta et al.: Experimental Production and Evaluation of Cement-Bonded Composite Pipes for Water Conveyance This indicates that the pipes could be of better use in drainage. Table 1. pH of the Water Samples after 24hours of pipe Immersion in Water REFERENCES [1] G.L. James, Principles of Farm Irrigation System Design. 2nd ed., Krieger Publishing Company, Malabar, Floride, USA, 1993. Cement + sand 7.6 Cement + sawdust 8.0 10% Eggshell 8.4 20% Eggshell 10.7 30% Eggshell 9.9 10% Carbide waste 8.9 20% Carbide waste 8.9 30% Carbide waste 9.1 10% Carbide waste + Eggshell 8.8 20% Carbide waste + Eggshell 9.6 30% Carbide waste + Eggshell 8.5 [2] G.O. Schwab, D.D. Fangmeier, W.J. Elliot, and R.K. Frevert, Soil and Water Conservation Engineering, 4th Edition, John Wiley and Sons Inc. USA, 1993. [3] R.W. Wolfe and, A. Gjinolli, Durability and Strength of Cement-bonded Wood Particle Composites made from Construction Waste. Forest Products Journal vol. 49 no. 2, pp. 24-31, 1999. [4] L. Price, E. Worrell and D. Phylipsen, Energy Use and Carbon Dioxide Emissions in Energy-intensive Industries in key Developing Countries. Berkeley (CA): Ernest Orlando Lawrence Berkeley National Laboratory, (LBNL-45292), 1999. [5] P.K. Mehta, Global Concrete Industry Sustainability. Concrete International, vol. 31 no.2, pp. 45–48, 2009. 4. Conclusions Water conveyance pipes were successfully produced using cement-bonded particleboard and partially replacing cement with eggshell and carbide waste respectively. Results obtained showed that the density, water absorption and thickness swelling of the pipes were generally within acceptable limits. However, the burst strength was relatively low compared to values reported in literature for polyvinyl chloride, asbestos and aluminum pipes. The eggshell apparently had more negative effect on the pipe properties than carbide waste. The relatively low burst strength, suggest that the composite pipes would better be put to use in activities that do not require high pressure water conveyance. [6] A.A. Semikolennykh, A.A. Rahleeva1 and T.B. Poputnikova, Spent Carbide Waste Retains Toxicity Long Term after Disposal in Caves and Mines. Acta Carsologica, vol. 41 no. 1, pp. 129–137, (2012). [7] S. Shuhadah, M. Supri, and H. Kamaruddin, Thermal Analysis, Water Absorption and Morphology Properties of Eggshell Powder Filled Low Density Polyethylene Composites. In: Proceeding of MUCET, UniMAP, Kangar, pp. 15-16, (2008). [8] A. H. Abdullah, I. Rusel, D. Salim and A. S. Abdulwahab Water Absorption and Mechanical Properties of High Density Polyethylene/Egg Shell Composite, Journal of Basrah Researches (Sciences), vol. 37, no. 3A, pp. 15, 2011. [9] Y.O. Oyebode and K. Ogedengbe, Some Mechanical Properties of Bamboo (Bambusa Vulgaris, Schrad). African Journal of Environmental Studies, vol. 2, no 1, pp. 108-112, 2001.

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