Catálogo de publicaciones - revistas

<jats:p>This paper presents the development of knowledge management factors affecting to construction project performance model of UAE construction company. The data used to develop the model was collected from questionnaire survey on large construction company in UAE. The respondents were the employees of the construction company that were requested to gauge each of the knowledge management factors using 5-points Likert scale that they perceived affecting the company performance. A total of 291 valid responses were used for this analysis. After the model was constructed, it was evaluated at the measurement component of the model where it involved examining the indicator reliability, convergent validity, and discriminant validity. Then at structural component, it involved checking the strength of the relationship, checking coefficient of determination, conduct predictive relevance of the model, calculate goodness-of-fit (GOF) and conduct hypotheses testing. It was found that two out of four constructs are significant which are having t-value above the cut-off value of 1.96. The significant relationships are knowledge management technology (KMT) and knowledge management process (KMP) toward project performance. These outcomes are from actual perception from the respondents where the collected data is not strong enough to trigger the significant relationship of other constructs that had been hypothesised. The model can help to give better understand to parties that concerned the knowledge management in construction industry.</jats:p>

<jats:p>To improve the soft grounds, soil stabilization has been used widely in many tropical countries including Vietnam. This paper presents the experimental study on the use of the modifying agent for expansive soil stabilization. A real-scale one-kilometer rural road was used for the experimental test. It was divided into four parts, and each part was subjected to different stabilization tests. The specimens extracted from every quarter were denominated as Q1 (soil + cement), Q2 (soil + cement + fly ash), Q3 (soil + cement + fly ash + modifying agent) and Q4 (soil + cement + modifying agent). The assessment test showed that specimen Q1 yielded the highest water absorption percentage after 24 hours and 72 hours of soaking. The longer the soaking time, the more water diffusion occurred at specimens Q1 and Q2 rather than at specimens Q3 and Q4. When subjected to the unconfined compressive and indirect tensile tests, specimens Q1 and Q3 yielded the lowest and highest strength, respectively. The use of the modifying agent in the specimens Q3 and Q4 has improved noticeably unconfined compressive strength, indirect tensile strength, and water stability compared to the specimens Q1 and Q2. However, ettringite-based sulfate heaving might be exhibited with the use of fly ash, this may cause damage to the overlying pavement structure in the long term. Therefore, to improve the expansive soil stabilization using the modifying agent, it is recommended to use the constituent materials in specimen Q4 rather than in Q3.</jats:p>

<jats:p>Structures in stabilized Compressed Earth Blocks (CEB), and more precisely the exterior walls (exposed to rainwater) or interior walls (exposed to spray water room, e.g.: bathroom) constructed with sand clay of class 2, suffer from decrepitude and crumbling, which are degradations due to environmental stresses. In order to solve this problem of degradations, it is necessary to find a minimum dosage level of cement that ensures the resistance to rupture and environmental stresses, in particular the aggression from rainwater and/or rise in moisture by capillarity, penetration by gravity, by suction or internal condensation. Two tests of durability have been conducted to simulate the two phenomena. These are a cyclic test of alternated wetting and drying to simulate the phenomenon of rise in moisture and a spray test to simulate the aggression from rainwater. The results of these tests show that a minimum dosage of 10% is sufficient to strengthen durably the walls against environmental stresses.</jats:p>

<jats:p>This research paper examines the comparative study on strength characteristics of a Cold rolled steel with castellated beam under the lateral distortional and torsional buckling modes. For studying a beam element, a STADD model is built. In the examination of cold formed steel sections, material non-linearity and geometric imperfection were taken into account. Variations in length and cross section of a finite element model were investigated. For cold formed steel sections and castellated beams, the load deflection curve is plotted and examined. To investigate the strength and behaviour of castellated steel beams, finite element modelling was used to modify the cross section. The study shows that the web distortional buckling has greatly influenced by the failure load in castellated steel beam. The failure load of the beam is influenced by the steel strength; the higher the steel strength, the higher the failure load. The high strength castellated steel beam fails due to local flange buckling, whereas the regular castellated steel beam fails due to lateral torsional buckling in the web.</jats:p>

<jats:p>Damage to rubble mound breakwaters (RMBs), both general and partial, causes instability and inconstancy of the structure against waves. This study aimed to investigate the effect of a submerged obstacle on the stability and damage reduction of RMBs as an innovative method and determine the optimal distance of the obstacle from the breakwater and the floating wave barrier based on the damage parameter. The waves affecting the breakwater were assumed to be random using a JONSWAP spectrum. The aggregates' movement and the RMB's exact deformation were recorded using close-range photogrammetric imaging, and the eroded area and the damage parameters were obtained at equal distances in eight cross-sections. According to the results of the tests, by analyzing the effect of the number of waves hitting the breakwater, 3000 waves were considered to bring the structure to a stable state. The results showed that increasing the relative wave height from 0.36 to 0.48 and from 0.48 to 0.6 increased the damage parameters to 39.12% and 44.44%, respectively, and increasing the relative wave period from 0.6 to 0.8 and 0.8 to 1 increased the damage parameters to 22.94% and 28.26%, respectively. Moreover, using a seaward obstacle at 0, 5, 10, 15, and 20 cm distances decreased the damage parameter. The greatest effect, a reduction of 39.15% in the damage parameter, was observed at a distance of 5 cm from the RMB. This number was reduced to 0.735 when a floating wave barrier was used without a submerged obstacle (i.e., 34.14%). Using an obstacle at 5 cm in conjunction with a wave barrier reduced the damage parameter by 54.03% and demonstrated the best function among different models. Hence, this model is proposed based on the experiments carried out in this study.</jats:p>

<jats:p>A considerable amount of the globally produced ceramic goes to waste daily. Ceramic wastes that are sent to the landfills have negative effects on soil, water, and the environment, as they contain aluminum, silica and iron oxide. The waste water leaching to the soil contains insoluble particular matter or heavy metals and could damage the plants. The air emission of the ceramic waste dumping process is also very high and it has negative effect on environment and human health by spreading dust. Using waste ceramic dust in soil stabilization could be for better disposal of such waste. The usage of natural resources can be minimized as well as prevent additional environmental burden and emissions. For this purpose, three local clay soil samples from Erbil in North-Iraq were gathered and the effects of addition of waste ceramic dust on mechanical properties of these samples were experimentally examined in two different grading sizes. The ceramic dust with particle sizes passing sieve No.40 and sieve No.10, in the proportion of 0, 5, and 10% percentages were used. The study showed that with an increase in ceramic dust percentages, liquid limit, plastic limit, plasticity index, optimum moisture content of the clay decreased. On the other hand maximum dry density, unconfined compressive strength and California bearing ratio increased. The study showed that addition of No.10 gradation ceramic dust results in higher improvement compared to the same amount of ceramic dust in No.40 size. The current work concludes that soil stabilized with the right type and ratio of ceramic dust could be suitable for a sustainable highway construction subgrade by reducing the design thickness and potentially be more economic.</jats:p>

<jats:p>The application of post-occupancy evaluation (POE) has increased recently, owing to the methodology's ability to improve building performance. However, the procedures employed vary depending on the building's suitability and category. Therefore, this study aims to provide a comprehensive survey to explore the state-of-the-art POE research. Bibliometric analysis was used to retrieve 381 POE publications from the Scopus database between 1979 and 2020. VOSviewer software was applied for the visualization and scientific mapping of literature. The study helps researchers understand by offering comprehensive data about the most literate nation contributions, publications' significant sources, and devoted authors to POE publications. The findings revealed that the United States, the United Kingdom, and China had rendered the three most literature contributions; Building Research and Information were the top publication's significant source titles, and Hassanain, M.A. is incredibly devoted to POE publication. Research hotspots in the POE focus on building performance, architectural design, and sustainable development. The primary themes in POE concentrate on comfort, sustainability, performance, design and criteria. Future research should emphasize that POE is used on heritage buildings to ensure that these buildings perform well for sustainability. It will significantly value the people involved in the design, construction and also conservation practice.</jats:p>

<jats:p>This study introduces a novel attempt of utilizing used cooking oil (UCO) and fly ash in the production of green roofing tile, namely UCO-GRT. UCO was utilized as an alternative binder to fully replace the cement and clay, while fly ash was used as a fine aggregate instead of virgin sand. This can maximize the percentage of waste substitution in the manufacturing process, consequently reducing the waste disposal issues encountered in Malaysia. The optimization process was carried out to investigate the optimal manufacturing parameters, by considering the curing duration, the composition of UCO and fly ash, and the composition of catalyst incorporated. The mechanical properties of UCO-GRT produced, including density, dry and wet transverse strength, percentage of water absorption, and permeability have been investigated. Findings reveal that the utilization of catalysed UCO and fly ash solely in the production of roofing tiles is feasible. The optimized UCO-GRT fulfilled the basic requirements of a high-profile roofing tile as per ASTM standards. The embodied carbon and embodied energy of the novel roofing tile was also studied and compared with the cementitious and clay roofing tiles.</jats:p>

<jats:p>This case study questions the possibility of using the prefabricated modular panels for building nZEB homes in earthquake-affected areas in Croatia. The comparison of the traditional and prefabricated construction was made in terms of construction costs and time, and energy consumption. Four cases of a ground floor family house were simulated in this research: two using modular prefabricated panels and two built traditionally with hollow brick. The energy consumption of all houses was compared to the current Croatian nZEB requirements. Furthermore, the costs, durability, and construction time of prefabricated and traditionally built houses were compared. The results showed that although prefabricated houses consume less energy, and experience lower thermal losses, they are slightly more prone to overheating in the summer. Finally, it was concluded that prefabricated houses are the best solution for current earthquake-caused situation due to their construction time which is significantly shorter compared to the traditionally built houses.</jats:p>

<jats:p>Today researchers all over the world are focusing on ways of utilizing either industrial or agricultural wastes as a source of raw materials for the construction industry. This is used to minimize the emission of CO2 during the manufacturing of cement. One of the agricultural waste products is coffee husk which is found in large amounts in Ethiopia. This paper aims to characterize the physical and chemical properties of Coffee Husks Ash (CHA) by using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Fourier Transforms Infrared Spectroscopy (FTIR) tests, and also the experiment were conducted to determine the compressive, split tensile and flexural strength of the material and durability tests were determined. The result have shown that, when the replacement percent further increases, the crystalline material increases, silicate concentration decreases, and also the micro pores or air void are increases, which may lead to decreasing the strength of concrete. In the case of mechanical property of concrete, there has been remarkable increment up to 5% CHA replacement and also strongly satisfied up to 10% replacement, furthermore increasing CHA replacement up to 20% are optimum dosage of normal concrete mix production of C-25 concrete. Finally, water absorption and sulfate attack of partially replaced concrete is shown as an improvement in the durability of concrete.</jats:p>