scholarly works
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Item Hydration behaviour and infrared spectroscopy of pre-treatments effects on portland cement-eremospatha macrocarpa and laccosperma secundiflorum systems(Asian Network for Scientific Information, 2012) Adefisan, O. O.; Fabiyi, J. S.; McDonald, A. G."The effects of cold water extraction, incorptation of calcuim chloride (CaCl2) and aluminium sulphate (AL2(SO4)3) on the setting time (tmax), maximum hydration temperature (Tmax), time ratio(tR) and surface chemistry of Eremospatha macrocarpa and Laccosperma secundiflorum particles mixed with Portland cement was investigated. The mixtures were placed in thermally sealed thermos flasks for 24h after which tmax, Tmax and tR were measured. The tmax,Tmax and tR were 12.4 and 11.9h, 59.1 and 58.3oC, 1:1 and 1.1, respectively for untreated E.macrocarpa and L.secundiflorum and ranged from 5.2 to 10.7h, 57.7 to 83.7 oC and 0.5 to 0.9, respectively when treated with cold water and chemical addictives. Cold water extraction and chemical addictive significanlty improved the hydration parameters of rattan-cement system. CaCl2 performed better as a chemical accelarator than Al2(SO4)3 while L. secundiflorum inhibited cement setting more than E.macrocarpa. Infrared spectroscopy showed that incorporation of CaCl2 to L. secundiflorum particles helped expose cellulose to advance participation thereby enlarging its surface area for interpretation networking with cement. "Item Strength and sorption properties of cement bonded composites made from calamus deerratus and laccosperma secundiflorum canes(Tertiary Education Trust Funds, Nigeria, 2012-04) Adefisan, O. O.; Olorunnisola, A. O."Two layers rattan cement composites were made from Calamus deerratus and Laccosperma secundiflorum particles using cement: sand:rattan mixing ratios of 1:2:0.2 and 1:3:0.2 and calcium chloride (CaCl2) at two levels 0% and 3% (by weight of cement) and subjected to static bending and sorption tests after production. Results showed that rattan-cement mixes had low moduli of rupture, thickness swelling and water absorption rates but high moduli of elasticity and are suitable for low stress out-door applications. While the Calamus composites generally had low strength and high sorption properties than the Laccosperma cement mixes, peeling significantly reduced the strength properties of the Calamus cement composites possibly due to higher presence of cement inhibitors. Addition of CaCl2 significantly enhanced both the strength and sorption properties of composites made from Calamus and Laccosperma particles "Item Production and testing of wood-plastic composites boards from mixed particles of gmelina arborea and khaya ivorensis(Forest Research Institute Malaysia, 2012) Adefisan, O. O."A lot of wood waste is generated from wood species in the Nigerian wood mills which are hazardous to the mill, mill workers and the wood. These wastes can be incorporated into plastic composites to manufacture value added products for interior and exterior applications in housing construction. This work examined the production and testing of plastic composites from mixed sawdusts of Gmelina arborea and Khaya ivorensis. Mixed sawdust of G.arborea and K. ivorensis collected from mills were screened, dried, milled to 0.4mm particle size, blended with polyvinylchloride (PVC) and chemical additives (calcium carbonate, talcum, calcium, magnesium and zinc stearate) in ratios 3:16:1;5:14:1 and 7:12:1. The mixes were extruded at barrel and die temperatures of 140oC and 165oC conditioned at temperature of 20oC and relative humidity of 55%. Specimens were cut from the products and tested for flexural and sorption properties in comparison with those of locally sourced commerical 100% PVC. The moduli of rupture and elasticity of the plastic composites were between 13.2 to 22.9 N/mm2 and 1254.0 to 3346.7 N/mm2 respectively as against 2.4N/mm2 and 902.0N/mm2 for 100% PVC while the impact strength ranged between 5.0 to 7.9 N/mm2 in comparison with 2.1N/mm2 for 100% PVC. The results obtained revealed that the flexural properties were superior to those of commercial 100% PVC and increased with increasing wood content. The plastic composites produced were dimensionally stable with low sorption rates and were suitable for moderately stressed interior and exterior purposes. "Item Effects of particles size, composite mix and cold water treatment on the compressive strength of eremosphatha macrocarpa-cement composite(Forest Research Institute Malaysia, 2012) Adefisan, O. O.; Idris, A.; Ojeabulu, J.Effects of particle size, composite mix and cold water treatment on the compressive strength of Eremospatha macrocarpa–cement composite. Rattan–cement composites were manufactured using different particle sizes (0.60, 0.85 and 1.18 mm) of untreated Eremospatha macrocarpa cane and those treated in cold water using cement–sand ratio of 1:3 and 10% of rattan based on the cement mass. Specimens were tested for compressive strength after 28 days of curing. Increasing the particle size and inclusion of sand in the composite mix reduced the compressive strength while pre-treatment with cold water enhanced the compressive strength. The compressive strength of E. marcocarpa–cement composites was influenced by the interactions of pre-treatment and particle size as well as pre-treatment, particle size and composite mix.Item Influence of pre-treatment on the compartibility of maize cob cement mixture(The Forest Association of Nigeria, 2011-07) Adefisan, O. O.The effects of pre-treatment: aqueous extraction, addition of 3% calcium chloride (CaCl2) and combination of aqueous extraction and 3% CaCl2 on maximum hydration temperature (Tmax), setting time(tmax) and time ratio indices (tR) of locally sourced maize cobs mixed with portland cement were investigated. Aquenous extraction reduced the tmax, Tmax and tR while chemical treatment and combination of aquenous extraction and chemical treatment reduced tmax and tR but increased Tmax of the maize cob-cement mixes. Generally, untreated maize cobs were moderately suitable for cement bonded composites production. Pre-treatment with 3% CaCl2 improved the compartibility of maize cobs with cement than either aquenous extraction or combined treatment with aquenous extraction and addition of 3% CaCl2. The result of this work showed that utilisation of maize cob for composite production can serve as avenues for creation of waste to wealth and thus cushion the over-exploitation of timber-resources.Item Strength and sorption properties of plastic composites made from eremospatha macrocarpa and laccosperma secundiflorum canes(2011) Adefisan, O. O."The dwindling timber resource and the attendant shortage of wood supply call for alternative furnish for composite production. Rattan canes are candidate materials due to their availability, renewability and inexpensive processing cost. This work therefore examined the feasibility of using rattan canes as reinforcements for plastic composites production by evaluation the strength and sorption properties. Particles extracted from Eremosphatha macrocarpa and Laccosperma secundiflorum canes harvested from wild stocks were milled into 0.4mm, dried to 0.5% moisture content, blended with high density polythylene (HDPE), talcum, zinc stearate Ethylene bistearamide (EBS) wax in the ratio 1.0:0.82: 0.12:0.04:0.02 respectively and extruded using rotating twin-screw at barrel and die temperatures of between 149 and 193 oC. The composite were cut to sample sizes and tested for flexural properties on a universal testing machine while sorption properties were evaluated after 2 and 24 hours immersion in water. The results obtained revealed that the respective moduli of ruputre and elsaticities of the E. macrocarpa and L. secundiflorum composites were 26.2 and 26.4 N/mm2 and 2689 and 3406 N/mm2 while the water absorption were between 1.2 to 3.1% and 1.0 to 2.4% and thickness swelling were 0.4 to 1.0 and 0.3 and 0.9% after 2 and 24 hours immersion in water. The study revealed that rattan canes were suitable as reinforcement for plastic composite production, dimensionally stable with low water absorption and thickness swelling rates and can be applied for both structural and non-structural interior and exterior purposes. Differences in the rattan anatomy influenced the ductility and sorption properties of the plastic composites "Item Suitability of eremospatha macrocarpa canes for the production of cement-bonded composites(Forest Research Institute Malaysia, 2011) Adefisan, O. O."The suitability of untreated Eremospatha macrocarpa canes for cement-bonded composites (CBCs) and the effect of cold water pretreatment on the compatibility of the species with cement were investigated using the hydration test approach .Eremospatha macrocarpa particles were mixed with cement and water, and placed in insulated thermos flasks. Temperature rise was monitored for 24 hours. Suitability of the species for CBC production was assessed based on setting time (tmax), maximum hydration temperature (Tmax) and time ratio (tR). The tmax, Tmax and tR of the cement composites ranged from 7.2–8.5 hours, 55.0–57.1 °C and 1.2–1.4 respectively. Pretreatment of particles with cold water reduced the tmax, Tmax and tR of the cement composites by 15.3, 3.7 and 14.3% respectively. Cold water pretreatment significantly improved the compatibility of untreated particles of E.macrocarpa with cement. "Item Effects of selected pre-treatment methods on the hydration behaviour of rattan-cement mixtures(KFRI, 2010) Adefisan, O. O.; Olorunnisola, A. O."The influence of clacium chloride (CaCl2), magnesium chloride (MgCl2), hot-and cold-water pre-treatments, and prolonged storage on the hydration behaviour of particles extracted from Calamus deerratus and Laccosperma secundiflorum rattan canes mixed with cement was investigated. While the untreated rattans inhibited cement setting, pre-treatments generally improved compatibility.The addition of chemical additives and aquenous pre-treatments enhanced the compatibility of the rattan-cement composites while peeling of silicified epidermis generally reduced the compatibility parameters. Pre-storage positively influenced the hydration behaviour of the L.secundiflorum composites while it negatively affected the Calamus composites. Statistical analyses revealed that all the pre-treatment methods employed significantly improved the hydration behaviour of the rattan-cement mixes except water and CaCl2 treatments. The compatibility indices based on the maximum hydration temperature (Tmax),compatibility factor (CA), setting time (tmax) and time ratio indices (tR) did not consistently predict the hydration behaviour of the rattan composites. A modified time ratio index based on the threshold temperature (40oC) is proposed for prediction of the hydration behaviour of rattan-cement mixes "Item Effects of selected pre-treatment on the setting of cement composite from two rattan species(2009) Adefisan, O. O.; Olorunnisola, A. O."The effects of aqueous extraction and removal of silified epidermis from rattan canes on the maximum hydration temperature (Tmax) and setting time (tmax) of two rattan canes species, Calamus deerratus and Lacosperma secundiflorum, mixed with portland cement were investigated. Tmax ranged from 37.0 to 58.66oC for the C.deerratus and L.secundiflorum composites respectively while tmax was from 3.7 to 26.5hrs and 7.4-25.7 hrs. Aqueous extraction increased the Tmax and reduced the tmax of the rattan-cement mixes while removal of epidermis generally caused reduction in both Tmax and tmax. The two rattan species seemed more amenable to cold than hot water extraction. Although cement extraction improved the tmax of the Calamus-cement composite more than Lacosperma cement composite. Epidermis removal, species, aquenous pre-treatment and their interactions had significant effect on the setting time than of the rattan-cement mixes. "Item Compability of calamus Deerratus and lactosperma secundiflorum rattan particles with ordinary portland cement(2007) Adefisan, O. O.; Olorunnisola, A. O.An investigation was conducted to determine the optimum water to cement ratio for a locally manufactured portland cement for use in wood composites. The effects of pre-processing and calcium chloride (CaCl2) on the compatibility of two rattan canes ( Calamus deerratus and Lacosperma secundiflorum) with cement were also assessed using the compatibility factor (CA) approach. An optimum water: cement ratio of 0.45 was obtained. Generally the two rattan species were compatible with cement. The CA factors increased with increasing levels of CaCl2 concentration (65.2% to 101.5% for C.deerratus and 71.2% to 103.5% for L. secundiflorum at 0 to 3% concentrations). Removal of the silified epidermis (pre-processing) had more significant effect (p< 0.05) on the compatibility of C. deerratus with cement than in the L. secundiflorum species. Also, the particles of the Lacosperma species were more compatible with cement than those of the Calamus species probably due to the anatomy and other variations in the two species.