Materials Science Forum Vol. 997

Abstract: The usage of agricultural waste in form of ashes as one of the constituent materials in concrete has been studied in recent years. Palm Oil Fuel Ash (POFA) is one of the largest agricultural wastes produced in Malaysia that contain high amount of silica with pozzolanic properties. The mass production of POFA are typically disposed to open area and in turn can generate environmental issues and health hazards. Due to the waste disposal problem, a number of initiatives have been done by utilizing POFA into various construction materials including as substitute to Ordinary Portland Cement (OPC) in concrete production. This paper discusses on the water absorption properties and compressive strength of concrete by utilizing POFA in several series of cement replacement. OPC was replaced by POFA at 2.5%, 5%,7.5% and 10% in these series of mix design. Control OPC concrete sample was also prepared for comparison. The samples were prepared in 100 mm cubic moulds and tested for compressive strength and water absorption for 7, 14 and 28-day curing ages. Three replicates were prepared for each concrete mix and for each test conducted. The results stipulated that the higher percentage of POFA replacement decreased the compressive strength and increased the water absorption amount of concrete mixture over different concrete ages.

Abstract: Clay fired bricks are commonly encountered in the construction sector as infill between structural frames. This system has been favoured by builders due to familiarity, ease of manufacture, and they also do not require skilled labourers to erect. Produced from moulded clay and hardened by firing in a kiln, brick production is both energy intensive and high in CO₂ emission. Fired bricks are typically held together by cement mortar at the bed and perpend joints which provide very minimal resistance against shearing or flexure. This meant brick walls often require additional wind posts or stiffeners to provide stability. Compressed earth masonry offers an alternative to the conventional brick walling system in that, besides having the advantages of conventional bricks, they also confer higher compressive strengths due to the high-pressure compaction manufacturing process. The high strength allows the system to be adapted into load-bearing masonry system for use in low-rise buildings as an alternative to the more expensive reinforced concrete or steel framing system. The high-pressure compaction process along with high quality moulds also give fair-faced finished to the bricks, allowing them to be used as facing bricks and eliminating the need for surface finishing such as plastering. Additionally, compressed bricks featuring interlocking key holes along the bed joints allows for simplified and faster wall erection process. This review paper aims to document the research progress thus far in adopting the compressed interlocking bricks as a sustainable alternative to current building materials.

Abstract: Soft soil is normally associated with high moisture content and fine content which result in high compressibility and low strength. However, a proper treatment such as solidification by means of hydraulic binders is required in order to be usable for beneficial purposes (e.i backfilling). This paper experiments the effects of cement treatment on the one-dimensional (1D) consolidation behavior of a high moisture content (MC) soil (twice liquid limit), based incremental loading test. The effects of Portland cement addition are evaluated for dosages ranging from 0 % to 15% by dry mass of soil. After curing, it was found that 10 % cement was required to make meaningful reduction in MC for kaolin while no major difference was noted between after mixing and after curing for DMS. In kaolin the moisture content decreased by 6.5 % for each 5 % increment of cement. Similarly, the MC of DMS reduced by 10 % for each 5 % increment. Thus, the reduction, immediately after mixing, in DMS was higher by 3.5 % compared to kaolin. The most evident effect of the treatment feasibility is the development of a cementation-induced yield stress after 7 days of curing: the bigger the cement dosage, the greater the yield stress and the greater the vertical effective stress that can be sustained at any void ratio. The maximum yield stress at 15 % cement content was found 30 kPa and 70 kPa for DMS and kaolin respectively. The highest void ratio values were found in the control specimens (3.77) in kaolin and DMS (5.66) whereas the lowest void ratio was corresponded to 15 % cement 3.35 and 4.65 for kaolin and DMS respectively. The control specimens decreased dramatically from 38.93 m² / KN - 0.13 m² / KN and 36.03 m² / KN - 0.19 m² / KN for kaolin and DMS specimens respectively. The results correspondingly provide a consistent depiction of the effects of cement treatment on MC, void ratio and coefficient of volume compressibility. The effectiveness of the treatment is obvious compared to the untreated soil.

Abstract: In this study, raw wood (RW) samples were impregnated with a mixture of furfural alcohol (FA), styrene (ST), and nanoclay of varying concentration of FA and ST. These impregnated wood and RWsamples were then subjected to FTIR, water uptake (WU), and thermal studies. The FT-IR results at 1600-1800 cm^-1 showed that the ST/FA/clay-WPNCs had different peak numbers with different positions compared with the RW. So, there was an interaction between RW, FA, ST and clay. The WU of ST/FA/clayimpregnated wood is lower than RW. In thermo gravematric result, below 100 °C the impregnated wood samples had less weight lost compared to RW.

Abstract: Nearshore’s facilities are often require frequent and regular maintenance dredging in maintaining appropriate water depths and enlarging the access channel and turning basin. A large amount of sediment was spawned from the dredging work. The dredged marine sediments (DMS) are not apt to be used in construction activities because of its poor geophysical properties. The purpose of this research is to study the improvement in moisture content and strength of DMS by using electrokinetic (EK) method. DMS are classified as a high plasticity silt (MH) with 240.74 % of its natural water content. Stainless steel plate was invoked as the electrode, while distilled water (DW), citric acid (CA) and calcium chloride (CaCl₂) were applied as the stabilizing agents. The aforementioned stabilizers are electrically injected into the DMS which causing flow of the solutions through the pores in DMS under 50 V/m of applied direct current (DC). The results of treated DMS are presented in moisture content, undrained shear strength and SEM-EDX analysis. The EK treated DMS shows it increases in strength in the dry zone area after the 14 days treatment. The dry zone area was created near the anode and wet zone was made near the cathode. The application of calcium ions in the treatment had increased the strength and alters the pattern of the soil fabric. Largely, EK has significantly improved the quality of DMS even though the strength increase observed was not homogeneous throughout the specimen.

Abstract: The jute polyethylene composites were developed using the hot-press technique with different fiber weight ratios. Due to the hydrophilic nature of fiber, it exhibited poor interfacial interaction to hydrophobic polymer matrix. In order to enhance the interfacial interaction between fiber and polymer, the benzene diazonium salt (BDS), propionic anhydride (PA), and 3-isocyanatopropyl triethoxysilane (silane) treated jute were used for the manufacturing of composites in this study. The chemical resistance tests of prepared composites were performed in order to probe whether these are resistant to various chemicals such as: acids, alkalis, and solvents. The effect of chemical treatments of the composites have been investigated. It was observed that the fabricated composites were resistant to all chemicals except carbon tetrachloride. The treated jute composites showed higher chemical resistance than raw jute composite and silane treated jute composite yield the highest resistance which can be suggested for making the water and chemical storage tanks.

Abstract: Nypa fruticans or locally known as nipah palm is extracted from its fronds to determine its potential as reinforcement in polymer composites. The objective of this paper is to investigate the method to extract nipah palm fiber from its fronds and to determine its diameter and density. Two extraction methods were tested; they are the dry and wet method. The dry method is where the fronds are dried under hot sun and the wet method is where the fronds were soaked in water prior to extraction. The extraction process found that nipah palm has two types of potential fiber suitable for reinforcement, coarse (fiber A) and fine fiber (fiber B). Both extraction methods are able to produce these two fibers. Both methods are discussed extensively in this paper. The diameter of fiber A and B were 0.53±0.06 mm and 0.039±0.08 mm respectively. Distribution of the fibers was measured using optical microscope. The densities of the fibers were measured using pycnometer method and the densities were 1.00 g/cm³ and 0.89 g/cm³ for fiber A and B.

Abstract: Electrolyte as one of the major components in dye sensitized solar cells (DSSCs) plays an important role in dye regeneration and as the inner charge carrier transport between electrodes. Gel polymer electrolyte is a potential alternative to liquid electrolytes which suffer of leakage and solvent evaporation. In this present research, functionalization of chitosan by the quaternization reaction of chitosan with iodopropane forming tripropyl chitosan iodide is proposed for the preparation of gel polymer electrolyte. Tripropyl chitosan iodide was characterized by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Four different polymer electrolytes were tested at different compositions in presence of iodide/triiodide redox salt and imidazolium ionic liquid in DSSCs configurations. The results show that the gel polymer electrolyte containing the tripropyl chitosan iodide in presence of 1-propyl-3-methylimidazolium iodide ionic liquid showed better performance with power conversion efficiency of 0.415% as compared to the gel polymer electrolyte film without ionic liquid with power conversion efficiency of 0.075%. The results shown the synergistic effects of the polycationic tripropyl chitosan iodide with the ionic liquid 1-propyl-3-methylimidazolium iodide on the photovoltaic performance.

Abstract: In the present work, the surface morphology and electrical characteristic of different doping ratio of reduced Graphene Oxide (rGO) in Titanium Oxide solution with different organic dyes (turmeric and beetroot) were studied. The Titanium Dioxide (TiO₂) solution and reduced Graphene Oxides (rGO) were synthesized by using precipitation-peptization method and chemical reagent, respectively. The TiO₂-rGO thin film was deposited on the glass substrate by using doctor-blade technique. The surface morphology and electrical characteristic were measured by using Scanning Electron Microscope (SEM) and Keitheley 2450 Source Meter, respectively. Experimental results showed that 0.3 wt% rGO with turmeric dye resulted the highest value of open voltage (V_oc) and short circuit current (I_sc) of Dye-sensitized Solar Cells (DSSC).