• Computers and Concrete
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• v.25 no.2
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• pp.119-132
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• 2020

There is a growing interest in the use of by-product materials such as ceramics as alternative materials in construction. The aim of this study is to investigate the mechanical properties and durability of sustainable concrete containing waste ceramic powder (WCP), and to predict the results using artificial neural network (ANN). In this order, different water to binder (W/B) ratios of 0.3, 0.4, and 0.5 were considered, and in each W/B ratio, a percentage of cement (between 5-50%) was replaced with WCP. Compressive and tensile strengths, water absorption, electrical resistivity and rapid chloride permeability (RCP) of the concrete specimens having WCP were evaluated by related experimental tests. The results showed that by replacing 20% of the cement by WCP, the concrete achieves compressive and tensile strengths, more than 95% of those of the control concrete, in the long term. This percentage increases with decreasing W/B ratio. In general, by increasing the percentage of WCP replacement, all durability parameters are significantly improved. In order to validate and suggest a suitable tool for predicting the characteristics of the concrete, ANN model along with various multivariate regression methods were applied. The comparison of the proposed ANN with the regression methods indicates good accuracy of the developed ANN in predicting the mechanical properties and durability of this type of concrete. According to the results, the accuracy of ANN model for estimating the durability parameters did not significantly follow the number of hidden nodes.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.10-17
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• 2024

Rebar lap splice is the most commonly used at construction sites because it does not require any additional equipment or labor's skills. Rebar lap splice has high construction costs because they require approximately 15% more rebar due to the overlap length. To solve these problems of rebar lap splice, mechanical rebar coupler was developed. Mechanical rebar coupler has a strong bonding force, helping to keep the structure safe even during earthquakes. In addition, mechanical rebar coupler is suitable for modular construction and easy to construct, so the construction period can be shortened. And mechanical rebar coupler can reduce the amount of rebar compared to other joint methods, thereby reducing CO2 emissions. Despite these advantages, the use of mechanical rebar couplers is not widespread except in some developed countries. This is because the types and characteristics of mechanical rebar couplers vary widely, making it difficult for construction engineers to choose. Existing research has only been conducted on mechanical rebar couplers in terms of structural experiments. And there is no research that classifies and analyzes the shapes of rebars. Hence, it should be analyzed the characteristics of mechanical rebar couplers in terms of construction methods for each shape. Therefore, the objective of this study is a basic study on comparative analysis of the characteristics and performance of different types of mechanical rebar coupler for sustainable built environment. The most efficient mechanical rebar coupler was derived for each construction site environment.

• Advances in concrete construction
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• v.15 no.5
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• pp.333-348
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• 2023

Fast infrastructure development boosts the demand for shotcrete. Despite sand and stone being the most common coarse and fine aggregates for shotcrete, excessive exploration of these materials challenges the ecological environment. This study utilized an industrial solid waste, high-titanium heavy slag, blended with steel fibers to form Wet Shotcrete of Steel Fiber-reinforced High-Titanium Heavy Slag (WSSFHTHS). It investigated its workability, shotcrete performance and mechanical properties under different water-to-cement ratios, fly ash content, superplasticizer dosage, and steel fiber content. The tunnel excavation and support were investigated by conducting finite element numerical simulation analysis and was used in 3 tunnel lining pipes in Zhonggouwan tailing pond. The major findings are as follows: (1) The water-to-cement ratio (w/c ratio) significantly impacted the compressive strength of WSSFHTHS. The highest 28-day compressive strength of 60 MPa was achieved when the w/c ratio was 0.38; (2) Adding fly ash improved the workability and shotcrete performance and strength development of WSSFHTHS. The best anti-permeability performance was achieved when the fly ash constituted 15%, with the lowest permeability coefficient of 4.596 × 10-11 cm/s; (3) The optimum superplasticizer dosage for WSSFHTHS is 0.8%. It provided the best workability and shotcrete performance. Excessive dosage resulted in water bleeding and poor aggregate encapsulation, while insufficient dosage decreased flowability and adversely affected shotcrete performance; (4) The dosage of steel fibers significantly impacted the flexural and tensile strength of WSSFHTHS. When the steel fiber dosage was 45 kg/m³, the 28-day flexural and tensile strengths were 8.95 MPa and 6.15 MPa, respectively; (5) By integrating existing shotcrete techniques, the optimal lining thickness was 80 mm for WSSFHTHS per simulation. The results revealed that after using WSSFHTHS, the displacement of the tunnel surrounding the rock significantly improved, with no cracks or hollows, similar to the simulation results.

• Analytical Science and Technology
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• v.8 no.4
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• pp.1075-1078
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• 1995

This paper describes how industry has responded to the environmental challenge. Benefits include compliance with environmental legislation; genuine reductions to environmental impact; sustainable improvements to profitability in the face of increased competitive pressure. National and international Standards for environmental management offer security and direction for a company wishing to improve environmental performance and coupled with a waste minimisation strategy many financial and environmental benefits can be achieved. Introduction of new technical skills, techniques and worker understanding to aid motivation is an essential component of such a strategy. Monitoring and targeting has a key role to play in the establishment of improved environmental performance.

• Industrial Engineering and Management Systems
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• v.13 no.2
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• pp.118-128
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• 2014

This study examines how green operations affect firm's environmental performance with green innovation as a mediator in the context of electronic industry. We carry out an empirical study with 141 valid questionnaires collected from high-tech manaufactures in Taiwan. The results show that positive relationships exist among green operations, green innovation and environmental performance (in both operational performance and managerial performance). However, an integration of green operations with green innovation would influence firm's environmental performance more positively than the sole effects of green operations. It suggests that high-tech manufacturers should pay greater attention to green innovative strategies in order to cope with customer demand and, thereby, enhancing customer satisfaction and sustainable operations. This study has contributed to the extant literature by providing valuable academic references and pragmatic guidelines for firms to gain competitive advantages through green operations and green innovation.

• The Journal of Sustainable Design and Educational Environment Research
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• v.12 no.1
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• pp.25-34
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• 2013

As the construction industry develops, environmental pollution gets increasingly serious, giving damage including the increase of incidence of respiratory diseases and skin diseases among children with weakened immune systems, rather than adults. In daycare centers, infants and children spending much of their time, have high frequency of contact with the interior floor finish material. However, the majority of the child care centers don not use eco-friendly flooring but ordinary monorium flooring, because the initial investment cost of the eco-friendly flooring is higher than ordinary monorium flooring. Therefore, in this study, life cycle costs including the initial investment cost of the eco-friendly flooring and ordinary monorium flooring were calculated, demonstrating that the eco-friendly flooring is more economical than ordinary monorium flooring in terms of life-cycle cost. In addition, the analysis of the environmental performance also showed the excellence of the eco-friendly floor finishes. It is expected that the use of the eco-friendly floor finishes will increase due to their excellence in the aspect of life cycle cost and eco-friendly performance, through this study.

• KIEAE Journal
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• v.7 no.4
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• pp.113-118
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• 2007

From the construction material the cement and the concrete which will reach to 90% are used to construction. But the cement occurrence (from the whole industry 4.4% of carbon dioxide exhaust quantity) makes the carbon dioxide of manufacture hour and anti- the recognition which is an environment industry. The cement absorbs the carbon dioxide during life period of the life time. It calls carbonation. In this study in order to evaluate the carbon dioxide absorption of the cement test produced the mortar specimens which it follows in the W/C. And carbonatable material of mortar specimens (calcium hydroxide) the quantitly it measured, reference study it led and absorption of carbon dioxide quantity it produced. Finally two result comparisons leads and it is a fundamental study which does the test evaluation possibility and a propriety investigation of carbon dioxide absorption quantity in objective.

• KIEAE Journal
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• v.15 no.5
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• pp.67-74
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• 2015

This study aimed to develop a design manual to be used during the initial stage of the nearly Zero Energy Building (nZEB) design process. Recently, with the increased demand for nZEBs, there are many architects and architectural firms who are becoming interested in nZEB design. However, since the nZEB design process requires a different approach to the conventional building design process, architects have difficulties with application of the nZEB design process in their projects. Therefore, a design manual which can be used in the nZEB design process was developed in this study. Based on an intensive literature review, energy-saving strategies and their performance levels, which affect heating and cooling energy consumptions were established for a reference building. To analyze the sensitivity of each energy strategy to the overall performance, computer simulations using EnergyPlus were performed. At the same time, an Analysis of Variance assessment was conducted to estimate the relative importance of each energy factor. The energy sensitivity and priority of the energy factors was developed into a set of design guidelines.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.1
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• pp.181-193
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• 2014

The environment of supply chains is rapidly changed to global and eco-freindly work process. However, at current environment, it is not easy to grasp work flow and to analyze energy efficiency. Improving energy efficiency and visibility for goods flow can contribute to increases in customer attitudes and reductions in overall production costs Additionally, it can lead to increases in work efficiency and reductions in overall production costs. Until recently, efforts to improve energy performance focused on manufacturing industry. Those efforts have expanded to the supply chain. In this paper, we perform business process modeling about supply chain for visibility and sustainability - information and component flows - from assembly plants to logistics. This paper defines the work and information flows by modeling the underlying logical structures of the supply chain and the business processes that determine impact of visibility and sustainability. We model processes using the modeling methodology specified by UN/CEFACT. This methodology explains business process functionality and business transactions by UML diagram. The output of this paper would be useful in grasping work flow and capturing the used energy.

• Computers and Concrete
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• v.10 no.4
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• pp.391-407
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• 2012

Utilization of supplementary cementing materials (SCM) by the cement industry, as a highly promising solution of sustainable cement development aiming to reduce carbon dioxide emissions, necessitates a more thorough evaluation of these types of materials on concrete durability. In this study a comparative assessment of the effect of SCM on concrete durability, of every cement type as defined in the European Standard EN 197-1 is taking place, using a software tool, based on proven predictive models (according to performance-related methods for assessing durability) developed and wide-validated for the estimation of concrete service life when designing for durability under harsh environments. The effect of Type II additives (fly ash, silica fume) on CEM I type of cement, as well as the effect of every Portland-composite type of cement (and others) are evaluated in terms of their performance in carbonation and chloride exposure, for a service life of 50 years. The main aim is to portray a unified and comprehensive evaluation of the efficiency of SCM in order to create the basis for future consideration of more types of cement to enter the production line in industry.