Applied Mechanics and Materials Vols. 773-774

Abstract: Lightweight aggregate for concrete was produced by utilizing palm-based polyurethane (PU) as a substantial material. New types of green PU were prepared by reacting palm kernel oil polyol (PKO-p) with 2, 4-methylene diphenyl diisocyanate (crude MDI). Six attempts on rigid PU were investigated to determine the reaction time, density, compressive strength, and thermal conductivity. An additional polyol showed high density between 200-300 kg/m3. The compressive strength and thermal conductivity improved to 11.5 MPa and 0.060 W/mK, respectively. As a conclusion, the results of palm-based PU showed excellent properties established the lightweight aggregate and insulation material in the concrete technology.

Abstract: Fatigue crack of the precast reinforced concrete beam under repetition loading is vital to be examined. Reinforced concrete structures exposed to excessive repetition loading could lead to the failure of the structures. In order to examine the active fatigue crack, the reinforced concrete beams were subjected to three-point repetition maximum loading. Eight phases of maximum fatigue loading with sinusoidal wave, frequency of 1 Hz and 5000 cycles for each phase were performed on the reinforced concrete beams. The inspection was carried out with visual observation of the crack pattern and acoustic emission technique for each load phase. The signal strength of acoustic emission was investigated. It is found that the signal strength of acoustic emission and crack pattern of the reinforced concrete beam subjected to repetition loadings showed promising results for structural health monitoring.

Abstract: Titanium dioxide (TiO₂) is a material that contains photocatalysic which acts as self-cleansing agents on a material surface. In the application of TiO₂ in the civil engineering construction, it can be mixed with the fresh mortar known as TiO₂ mortar. Hence, a study on the characteristic strength of the TiO₂ mortar needs to be carried out. Moreover, the optimum dosage levels of the TiO₂ in the mortar can be determined. The characteristics of the TiO₂ were identified based on the compressive strength and flexural strength at 3, 7, 21 and 28 days. A total of five sets of specimens with different dosage levels were prepared and compared with the control specimen.

Abstract: Construction waste is a material of waste or excess building materials that are not used either in the original or debris from construction, structural repair, and improvement work, house demolishing, buildings and other structures. Wastes are from excess building materials from dredged material and stumps of structural repairs, improvements and work to destroy sidewalks, homes, commercial buildings and other structures. Construction waste also refers to soil, rock and vegetation removed during land levelling works or civil engineering works and works related to road maintenance. Illegal dumping site is places other than permitted facilities to dump waste such as transfer stations and landfills. The objectives of this study are; (1) identify illegal dumping of construction waste distribution in Parit Raja; (2) quantifying the illegal dumping of construction waste generated in Parit Raja and; (3) develop Geographic Information System (GIS) map for illegal dumping construction waste distribution in Parit Raja. In this study the location of the construction waste identified using Global Positioning System (GPS) in smartphone. Then the picture and material of construction waste was taken and identified. After that the volume of construction waste were determined using the pyramidal or rectangular shape measure. For the scattered waste, the weight were taken and converted to volume. Lastly the data was plotted and mapped in the GIS system. This study successfully create a database of construction waste generation in Parit Raja. The benefit of this study is it will help the management of waste in Parit Raja.Keywords:construction waste illegal dumping, database, GIS system

Abstract: In Malaysia, housing is divided into four categories, which are low cost housing, low medium cost housing, medium cost housing, and high cost housing. Demand and supply of housing is a major challenge to the country because it is one catalyst for social economic structure. The purpose of this research is to identify the factors of low-cost housing demand in Malaysia and to confirm the factors among experts in construction industry players in Malaysia. All factors are identifying from previous studies. Questionnaires are distributed among experts in construction industry players in Malaysia for confirmation. The data from previous studies are analyzed using frequency analysis table and the ranking of the factors are determined based on the highest frequency. Data from the questionnaires then analyzed using "Mean Rank" method. Ranking of the factors are determined based on the mean value adopted from SPSS 16 software. 27 factors of low cost housing demand are determined based on the previous studies. Results from previous studies shows that housing prices are on the highest ranking. 11 factors in the lowest ranking which are number of household factors, quality homes, adequacy, subsidies, marital status, mortgage rates, functions, benefits, job, family life, and culture. Meanwhile, results among experts in construction industry players in Malaysia show that affordable housing factors are in the highest ranking and marital status at the lower ranking. 92.1% of experts agreed that the factors are significant. Therefore, all the factors can be applied as low cost housing demand factors in Malaysia. Keywords:factors, low cost housing, demand,

Abstract: In this study several types of bricks were produced containing substituent from industrial wastes. The industrial wastes used are palm oil and electric power plant fly ash. These waste products are used to replace the natural ingredient in the manufacturing of brick clay namely as clay. Conventional bricks are produced from clay with high temperature kiln firing or from ordinary Portland cement (OPC) concrete. At the present, the world's natural resources are decreasing so many alternative actively pursued to ensure that the natural ingredients will remain unchanged for the use of the more significant and worthwhile. In this study, some suggestions have been proposed where the using of fly ash as a clay replacement materials in the percentage of 20%, 40% and 60%. The several laboratory experiments was carried out, where the high compressive strength with 20% of fly ash replacement is 15.5 N/mm² while for the 20% of power plant fly ash replacement provide a compressive strength of 103 N/mm². For optimum water absorption, the rate is 17.05% which is from 20% of palm oil fly ash replacement while for brick from 60% power plant fly ash, the rate of water absorption is 4.96%. Therefore, this study can contribute to recycling the industrial waste material as a replacement material in brick in Malaysia. Recycling waste is one way to ensure that waste management can be controlled.

Abstract: Green roof has shown potential contribution on improving the functional performance of buildings by lowering the roof exterior surface temperature, which is indirectly, could potentially reduce the energy demand. In addition, it is likely to provide important ecological services to urban areas through lowering of urban heat island (UHI) temperatures, increasing storm water retention and improves the biodiversity. This paper will then present the initial outcomes of the joint initiative between Malaysia Agricultural Research and Development (MARDI) and Universiti Tun Hussein Onn Malaysia (UTHM) in promoting this green technology in Malaysia. As green roof technology is still emerging, there is limited technical data available at present in Malaysian climate. The study aims to provide initial observation on the thermal performance of green roof and its effect towards surrounding and associated significant environmental benefit. In order to achieve the goal, the thermal performance of green roof system in experimental plot at MARDI had been monitored. The green roof experimental plot has been set up on two flat roofs in Horticulture Research Centre, MARDI, Serdang, Selangor and the treatments consists of two green roof system known as conventional system and self-watering system. The substrate depths were 50 mm and 100 mm. In addition, some observation on the attracted wildlife to the green roof was initiated. Based on the initial results, it is interesting to report that the temperature reduction for the green roofs on Roof 1 and Roof 2 were in averages of 6.1°C and 10°C, respectively. In conclusion, this joint study between UTHM and MARDI may facilitate the development of roof top gardening system in greening the urban area. With more studies, it will possibly highlight the engineering significance, furthermore promoting the application of green roof technology in Malaysia.

Abstract: Primarily due to contractors’ faults, construction industries in Malaysia have been facing problems such as delays, wastages, cost overruns and others. Inability of construction manager (CM) to efficiently manage construction projects is the major contribution to projects’ failure, and the lack of terms of reference on the technical competency for CM are believed to be the major setback. This paper reports the results of a preliminary study which was carried out to identify the technical competencies of CM. Exploratory mixed research methods were selected by employing qualitative and quantitative approaches. Multi-layered thematic analysis was embedded into literature analysis to maintain reliability and then validate through structured interviews. It was found that CM requires several technical competencies including managing staff, materials, labours, plants, sub-contractors, safety, money, quality, time, environment, administration, pre-construction, closeout and handover, responsibility to other parties, computer literacy, and administration of construction contract. Hence, the technical competencies for CM are believed to be exhaustive and holistic in singling out the appropriate technical knowledge and skills, and bring about numerous advantageous towards technically competent CM.

Abstract: Recently waste material pollution is a critical issue in every developing country. The factors such as increasing of growing population, daily and industrial activities will lead to these phenomena. These issues give an idea to use waste as a construction material that will give minimum impact towards the environment. Many researchers have been studied on waste material such as organic waste, sludge, fly ash, rice husk and processed waste tea into fired clay brick. In this study, the investigate on the incorporating of cigarette butts (CBs) was conducted. During this study, different percentages of CBs (0%, 2.5% and 5.0%) were added into fired clay brick. Meanwhile, different heating rates were applied during the firing stage, which are 1°C/min, 3°C/min and 5°C/min respectively. All samples were fired up to 1050°C. Leaching tests were carried out to investigate the possibility of heavy metals leached from the manufactured brick. The results demonstrated that, in terms of physical and mechanical properties, CB Brick (2.5%) at 1°C/min improved the most and leached low heavy metals. For IAQ test, CB Brick (2.5%) fired at 1°C/min is acceptable to be used as building materials since it complied with ICOP-IAQ.

Abstract: The proliferation of indoor airborne microorganism in public institutional buildings such as schools and universities is often regarded as a potential health hazards to the buildings’ users. This issue is not new in Malaysia, a country with humid climate which favours the growth of microorganism. However, there is lack of research’s data, especially in higher institutional buildings in this country. The assessment of the indoor air quality is conducted in a university’s two new commissioning buildings located at Southern Peninsular of Malaysia. Both buildings utilized centralized air conditioning system. Concentrations of airborne microorganism were determined using a single-stage impacter (biosampler) as per requirement of National Institute of Occupational Safety and Health (NIOSH) Manual Analytical Method 0800. The acquired readings were compared to the standard level determined in Industry Code of Practice on Indoor Air Quality (ICOP IAQ) 2010. Other parameters such as relative humidity, temperature, and air velocity were recorded along the assessment. The mean concentrations of the total bacteria at the affected area of the two buildings are 1102.5 CFU/m3 and 813 CFU/m3 respectively and it is significantly higher compared to the maximum exposure limit of 500 CFU/m3. While, the mean concentration of total fungi at the affected area for two buildings are 805.7 CFU/m3 and 509 CFU/m3 respectively which are both higher than the reading of outdoors and unaffected indoor area although slightly lower than the maximum exposure limit of 1000 CFU/m3. This study provides a glance of the poor indoor microbiological air quality in new higher institutional buildings in this humid region.