Catálogo de publicaciones - revistas

<jats:p>Slope failure or landslide is always ascribing to the slope sculptures in the hilly area. The trend of people building a structure on a hilly area has resulted in slope cutting works being carried out aggressively and, at the same time, has increased the risk of landslides. Most of the community lacks understanding regarding slope care and maintenance, which adds to the slope suffering. One of the factors contributing to slope failure is rainfall. The rainfall-runoff to the slope erodes the turfed and topsoil particles from the slope surface. When the slope surface is exposing to extreme weather, then the slope failure will occur. These failures pose a significant engineering hazard, necessitating urgent repair work and planning in many areas. All failures that occur will require expensive repairing costs. Therefore, this study is carried out to model the rainfall-induced slope failure occurrence at Kem Terendak, Melaka. This study utilises a simulation of slope stability analysis by limit equilibrium, Slope/W 2012 and finite element software for simulating groundwater flow in saturated steady-state situations, Seep/W 2012 in order to analyse the stability of the slope with the influence of climate. Through those analysis, one can understand the causes and mechanisms of the landslide. At the same time, the factors that influence the occurrence of failures can be identified and appropriate action can be taken to reduce or even eliminate the root cause of slope failures. In addition, effective and efficient slope repair methods can be proposed with optimal cost.</jats:p>

<jats:p>Visual comfort in office spaces improves not only productivity and wellbeing but also satisfaction and energy efficiency of the buildings. The objective of this research is to study the effect of one of the transporting daylighting systems (Anidolic Integrated Ceiling ‘AIC’) on the enhancement of the luminous interior environment and energy saving in office building through objective and subjective evaluations. The quantitative study was performed by measurement of the illuminance values in the physical model (1:4) under local luminous climate in two scenarios (with and without ‘AIC’) and by numerical simulation to calculate the daylight autonomy. The qualitative evaluations were achieved by using a field survey composed of four questions related to pleasantness, level of light and artificial lighting needs. Experimental study shows that the AIC offers high levels of illumination in quantitative terms result in moderate values of Daylight Factor (2% - 4%). Simulation results showed that more than 88% of energy consumption for electrical lighting can be saved. Subjective evaluation results indicate that in the test model (with AIC), 67% of participants felt more pleasant with the luminous environment, 74.19% considered that the level of light is sufficient and only 08 of 31 subjects need to use artificial lighting.</jats:p>

<jats:p>The strength characteristics of masonry is greatly affected by the brick strength, mortar strength and bond between brick-mortar interface. Especially, binding mortar significantly affects the shear and flexural strength of the masonry. In conventional masonry construction, river sand or natural sand is mixed with cement and used as binding mortar. However, due scarcity of good quality river sand, the extensive focus is on finding alternative materials for river sand for construction purposes. Quarry dust is one of the best alternatives for river sand, which can be used as fine aggregates in binding mortar. This study investigates the strength characteristic of the masonry made of quarry dust incorporated binding mortar instead of conventional cement-sand mortar. The binding mortar with four different river sand replacement levels of 0%, 33.3%, 66.7% and 100% quarry dust, was used for construction masonry. Compression test, direct shear test and cross-couplet test were conducted to evaluate the strength characteristic. The test results revealed that compressive, shear and bond strength of masonry was improved with increased quarry dust content in the binding mortar.</jats:p>

<jats:p>Construction and Demolition Waste (CDW), especially laboratory waste and concrete debris from construction, manufacturing errors, and demolition of existing structures, is posing challenges to the urbanization. As nowadays the aforementioned waste is disposed in landfills, this diminishes the development opportunity of cities. Although there are standards and research pointing out the application of recycled concrete aggregates in proper proportion, the theory has never been put into practice. This research aims to present feasibility of applying recycled aggregates through Bangkok’s economic perspectives. It is found that the investment in recycled aggregate plants takes nine years of payback period. Besides, the sensitivity analysis suggests that implementing certain strategies, such as imposing a landfill tax increase and applying dumping fee will significantly shorten the payback period of recycling business.</jats:p>

<jats:p>Nowadays, in Malaysia, one of the country's challenges is the improper management and disposal of solid waste. The leading sector that generates most of the solid waste in Malaysia is the agricultural sector from oil palm fibre, similar to oil palm trunk fibre, which is also be used as an additive in producing foamed concrete (FC). However, FC presents a weakness in tension, which can be reduced by adding an adequate volume of waste biomass by-product such as oil palm trunk (OPT) fibre. Accordingly, this study was undertaken to investigate the potential of utilising OPT fibre as a reinforcement in FC. There were four different volume fractions of OPT fibre: 0.15%, 0.30%, 0.45%, and 0.60% used as an additive to the FC mix. Two densities, 600 kg/m3 and 1200 kg/m3, were cast and tested. All FC specimens were then prepared and left to cure and exposed to the elements for 7, 28, and 56 days. In this study, to properties were examined: mechanical and durability properties. The results showed that the addition of OPT fibre in FC improved the compressive strength, flexural strength, tensile strength, water absorption, drying shrinkage, porosity and ultrasonic pulse velocity of the FC. OPT's surface roughness was proved beneficial for fibre to matrix interfacial bonding since a coarser surface permit OPT fibre and matrix interlocking in the hardened cement matrix. Based on the results of this study for 600 kg/m3 density, 0.30% volume fraction was the optimum amount added to the FC to achieve the best durability and mechanical properties. While for 1200 kg/m3, 0.45% volume fraction of OPT was the optimum percentage.</jats:p>

<jats:p>This research aims to examine the sulfate and chloride durability behaviors of geopolymer composites synthesized by the alkali activation of metakaolin (MK), reinforced by boron waste colemanite (C), silica fume (SF), and slag (S). The resultant geopolymer composites were subjected to magnesium sulfate (MgSO4) solution (concentration 10%), sodium sulfate (Na2SO4) solution (concentration 10%), and sodium chloride (NaCl) solution (concentration 10%) for up to 12 months. The compressive and flexural strengths, microstructure (X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)), weight changes, and visual inspection of the geopolymer composites were investigated to evaluate their durability behavior. The conclusion proved that the mix of a metakaolin with the addition of 10% C, and 20% SF shows the highest compressive strength for the studied range of mixture design. In geopolymer mortar samples, compressive strength increase was observed due to sodium chloride and sodium and magnesium sulfate effects after three months, while a decrease was observed after six months. These fluctuations were due to the diffusion of solutions in the matrix, formed during the transition of alkali ions from the samples to the solution. The loss of strength after three months could be due to the presence of microcracks, as a consequence of ettringite and gypsum creation in the pores, as well as the transition of alkalis from the sample matrix to the solution.</jats:p>

<jats:p>Increasing the capacity of structures especially bridges can be done by various methods, one of them is by strengthening. Strengthening using strands has been used in various constructions. However, strengthening in reinforced concrete beams has not been done much because it will have many difficulties in the implementation. The focus of this research is shear strengthening using non-stressing strands. Strand is attached to the beam with epoxy. In certain intervals, strands are also anchored on the vertical side of the beam with U-shaped reinforcing steel. The basis of the research is experimental testing in the laboratory. The test specimens have consisted of a specimen without strengthening (BU-Normal) and 2 specimens with strengthening (BU-SV1 and BU-SV2). Dimensions of specimens are 250mm x 400mm x 1700 mm. In the laboratory, all specimens are loaded by a monotonic static load until collapse conditions. The results of the loading test at yield condition show that BU-SV1 and BU-SV2 can increase shear capacity respectively by 13.735% and 10.300% when compared to beams without strengthening (BU-Normal). Whereas at the collapse condition, BU-SV1 and BU-SV2 can increase shear capacities respectively by 34.886% and 25.360% when compared to beams without strengthening (BU-Normal).</jats:p>

<jats:p>Palm oil boiler ash is a type of industrial waste from palm oil production, which abundantly disposed on landfill, and contaminate the soil and environment. Recently, boiler ash as a by-product is introduced as an additive in chemical stabilization, known as geopolymer. An alkaline solution functions to activate the silica-alumina structure bonding to replace the Ordinary Portland Cement in concrete application but few in soil stabilization study. This study investigates the strength of laterite with a geopolymer. Boiler ash was chosen as source material, with sodium hydroxide and sodium silicate mixed at a ratio of 1:2. Unconfined compressive test (UCT) and SEM were conducted for laterite soil with different geopolymer percentages. The test was conducted by adding a different geopolymer percentage at 0%, 5%,10%,15%, and 20% mixed with laterite soil. The soil sample was cured for seven days for an unconfined compression test (UCT). The result shows that the highest compressive strength was obtained at 15% of geopolymer in laterite soil at 340kPa. SEM tests show that the increased compressive strength was attributable to the 15% of the geopolymer, which had a compact and dense structure and less unreacted raw materials. In conclusion, the results indicated that 15% of geopolymer gives optimum value in enhancing laterite properties' strength. The findings support boiler ash usage as by-products in geopolymers' production for potential use in soil strength stabilization.</jats:p>

<jats:p>Decrement factor and time lag play an essential role in determining the thermal performance of a building envelope. Building walls, which form a major part of a building, have great influences on the energy consumption and indoor environment of a room. The indoor temperature considerably increases as the outdoor temperature increases. This scenario leads to excessive reliance on the mechanical cooling system, thereby increasing energy consumption. Therefore, this study aims to investigate the thermal performance and energy efficiency of different wall types. A building with a built-up area of 387.85m2 with six different wall materials is modelled and inputted in Energy Plus simulation software as an Intermediate Data Format file. The maximum and minimum surface indoor and outdoor temperatures are then obtained to determine the thermal performance of the wall material in terms of time lag and decrement factor. The energy efficiency of the wall materials is investigated by obtaining the annual cooling energy of the building made up of different wall materials. Results show that with the time lag of 1 hour, decrement factor of 0.86, annual cooling energy load of 9.52 GJ and cost consumption of RM 608.12, aerated lightweight concrete wall is the most suitable material amongst the six wall materials.</jats:p>