Abstract: Waste materials such as Pulverized Fuel Ash (PFA) is a possible alternative to reduce disposal activities and this study is to investigate suitability of PFA by conducting three laboratory tests namely unconfined compression test (UCT), shear box test (SBT) and plate load test. Both UCT and SBT to determine the optimum configuration of PFA that able to achieve the highest percentage of strength of PFA-cement-sand column, meanwhile plate load test is to study the effectiveness of using PFA-cement-sand column in the aspect of the bearing capacity for soft soil. In this study, it was investigated that by using the right configuration of PFA, cement and sand, it can produce a good product of sand column for the purpose of road construction. The highest shear strength was recorded is 93.51 kPa and the proportion of materials is 12%: 60: 28% (ratio of cement: PFA: sand).
Abstract: Epoxy coated reinforcements have been used extensively in bridge decks and substructures to protect against corrosion brought on by de-icing salts or marine environments. They need longer development lengths because of poor bond to concrete and special treatments on sites due to vulnerability of damage during transportation, storage and bending process. A new method of pre-heating of reinforcement before coating process using an IGBT(Insulated Gate Bipolar Transistor) control was applied to improve the bond of epoxy coating to reinforcements. In this paper, the bond-slip properties of newly developed epoxy coated bars are investigated and compared to those of black bars. The direct pull out test according to EN Standard was used with varying the diameters of reinforcements. The experimental results show that the new process is very efficient in increasing bond capacity of epoxy coated bars to concrete comparing those of traditional ones.
Abstract: The paper focuses on the study of the durability of cement mortars made with secondary crystallization additives. It investigates the influence of the crystalline additives on the degradation process of cement mortars exposed to gaseous CO2 and freezing cycles. The specimens with were tested for compressive and flexural strength at the following ages and after being treated by the following curing techniques: 28 days, 180 days and 25 freezing cycles, 28 days and 180 days in gaseous CO2. In order to explain the obtained results and to gain new information about the microstructure of the cement mortars being studied, the SEM sampling and RDA analysis were performed. The research results confirm an improvement in the resistance of cement based mortars using crystalline additives against cyclic freezing as well as gaseous CO2. An important parameter that influences the effectiveness of the crystalline additive is the curing conditions during the first 28 days of ageing.
Abstract: The pore structure of a material radically infuences its properties, such as strength, freeze-thaw resistance, capillarity or resistance to elevated temperatures. The character of the pore structure is also limiting for the intrusion of aggressive oxides into the material, which affects its service life. The paper describes how a crystalline additive influences the pore structure of cement mortars. It describes the effect of secondary crystallisation and the influence of the additon of PP fibers on the apparent porosity and the internal structure of the mortar. It also discusses the influence of aggressive conditions on the mortar’s pore structure.
Abstract: The article describes the accounting technique for concrete pressing and raised concrete deformation properties effect when calculating the bearing capacity of the pre-compressed concrete filled steel tube columns. Reliability of the received formulas and dependences is confirmed by experimental data. Due to the fact that the deformation properties of a concrete core in concrete filled steel tube columns significantly exceed the deformation properties of the uniaxial compressed concrete in similar designs, the possibility of high-tensile reinforcement effective use is provided.
Abstract: This research was carried out in order to study the effects that waste materials have on soil properties. As clayey soil has weak physical and mechanical properties, stabilizers are added in the soil to increase its strength .The waste materials were Palm Oil Fuel Ash (POFA) and lake water (waste water). The soil index properties was determined by carrying out the physical test and compaction test. A total of 50 samples were prepared which were tested for unconsolidated undrained Triaxial test and pH test to determine its relative mechanical and chemical properties. A shear strength of 17.80 kN/m2 was obtained for the control soil specimen of the mix of 0% of POFA on 7 curing days and the same soil specimen with similar percentage of POFA had a shear strength of 18 kN/m2 on 14 days. Moreover, the soil specimen of 80% of POFA and 30 % of tap water had a shear strength 44 kN/m2 at 14 curing days. On the other hand, the soil specimen at 80% of POFA and 30% of Lake Water displayed a shear strength of 37 kN/m2 on 14 days of curing was noted. The lake water was acidic at a pH of 6 while the tap water was at a neutral pH of 7. The control specimen (0% of POFA) of the mix of soil with tap water displayed a pH of 7 for all the curing days carried out while control soil specimen mixed with lake water displayed a ph of 6. The pH obtained increased in an alkaline way with increasing POFA percentages shear strength increased at a maximum pH of 11 at a soil specimen of 80% of POFA and 30% of Tap water proving POFA to be an alkaline material. It has been concluded that POFA, being a pozzolanic waste material can help in improving the mechanical property of the soil.
Abstract: Nowadays, plant biomaterials have been used in several types of industries for related purposes for example energy and electricity production, as our world is facing energy shortage problems. In this paper, the combustion behavior of a typical plant biomaterial, corn cob, was investigated using TG-DSC technique. Combustion experiments were conducted from room temperature to 900 °C at three heating rates of 10, 20 and 30°C/min in air atmosphere. It is observed that the process can be divided into three stages: dehydration (25°C-150°C), pyrolysis (150°C-380°C) and combustion (above 380°C). Besides, ignition and burnout temperature were investigated based on DSC profiles. Finally, two model-free methods (FWO and KAS) were adopted to perform the kinetic analysis for combustion reaction process. It is found that activation energies values against conversion rate present a rising trend (from about 172.40 KJ/mol to 326.95 KJ/mol) in the pyrolysis stage, while an opposite tendency was observed in the combustion stage (from about 365.55 KJ/mol to 202.86 KJ/mol), indicating that corn cob combustion is a complex process and relatively complex reaction schemes should be adopted to describe its combustion. It is anticipated that our current work could be helpful in providing reference to the design of energy conversion facilitates.
Abstract: Biodiesel is a bio-based fuel for diesel engine synthesized from renewable oils isolated from oil crops or animal. Biodiesel can be produced through transesterification where the process involves a catalyst and an alcohol. The most common catalyst for this process is homogeneous liquid catalyst. However, this catalyst system suffers from environmental problems. In order to eliminate the problem, we developed potassium loaded on coconut-shell activated carbon (K/AC) as heterogeneous solid catalyst which is easily regenerated, leading to more secure and more environmental friendly application. The purpose of the present work is to demonstrate the biodiesel synthesis from palm oil using K/AC catalyst in stirred tank reactor. Reaction variables such as methanol-oil molar ratio and temperature were optimized to reach the highest conversion for 4 hours reaction time. The highest reaction conversion, 26.98%, was obtained at methanol-oil molar ratio of 6:1 and reaction temperature of 60 °C. Furthermore, the value of collision factor, activation energy and standard enthalpy change of reaction obtained are 5.40 x 103 dm6.(mol.gcat.min)-1, 16.113 cal/mol and 5499.40 cal/mol, respectively.
Abstract: The supply of omega-3 fatty acids, which are EPA and DHA, was only 14.7% of the prospective demand calculated by using 500 mg/day/person as threshold limit for EPA and DHA consumption for a world population of 7.515 billion people. Alternative sources other than fish oil or seed-based-α linolenic acid (ALA) were necessary. Anaerobic digestion of palm oil mill effluent (POME) offered a new way for one of omega-3 fatty acids production, EPA. The digestion was conducted in anaerobic fluidized bed reactor supported by natural zeolite as the immobilization media. Process condition tried to be optimized was the pH level and the pre-treatment method (TSS filtration) before the digestion. Without any pre-treatment, the fatty acid profile produced after digestion contained considerable amount of polyunsaturated fatty acid with acidic condition provided higher EPA purity. On the other hand, pre-treatment led the digestion to produce saturated fatty acids with acidic condition provided very high purity of butyric acid as the product.
Abstract: The potential of Empty Fruit Bunch obtained from palm oil tree as a low-cost adsorbent is a sustainable approach in wastewater treatment. The objective this study to investigate the capability of EFB for removal colour from natural rubber wastewater as well as the influence of adsorbent dosage, pH, shaking speed and contact time. The results of the analysis show that all selected factors exhibit significant effect on removal of colour. Maximum removal (87.1%) for colour was achieved at 3.5 g of adsorbent dosage, pH 7, 150 rpm of shaking speed, 120 min of contact time. The Langmuir isotherm (R2 = 0.9913) described colour adsorption slightly better than the Freundlich isotherm (R2 = 0.9805), suggesting a monolayer adsorption behavior of the adsorption processes