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The Characteristics of Asphalt Concrete Binder Course (AC-BC) Mixture with Bottom Ash as Aggregate Substitute 底灰替代沥青混凝土粘结层(AC-BC)混合料的特性
Pub Date : 2015-03-20 DOI: 10.9744/CED.17.1.29-37
Sugiyanto G., Harmawan A., Mulyono B.
Highways serve nearly 80-90% of the population mobility and flow of goods. Utilization of bottom ash, a waste from coal combustion, in highway construction is one of the alternatives to reduce environmental pollution and support Clean Development Mechanism Program of Kyoto Protocol. The aim of this study is to analyze the characteristics of AC-BC mixture that uses bottom ash as partial substitute of fine aggregate and comparing with a standard mixture. Laboratory tests are performed on two different types of mixtures. The tests show that optimum asphalt content for AC-BCStandard mixture is 5.20% while AC-BCBottom Ash mixture is 5.25%. Bottom ash has higher porosity along with a little break field and has round shape so that the asphalt absorption is bigger than the crushed stone. Bottom ash can be used as an alternative aggregate to increase the value of flow of the AC-BC mixture, thus converting waste to valuable material.
高速公路服务于近80-90%的人口流动和货物流动。在公路建设中利用燃煤产生的底灰是减少环境污染和支持《京都议定书》清洁发展机制计划的替代方案之一。本研究的目的是分析底灰部分替代细骨料的AC-BC混合料的特性,并与标准混合料进行比较。对两种不同类型的混合物进行了实验室测试。试验表明,ac - bc标准混合料的最佳沥青掺量为5.20%,ac - bc底灰混合料的最佳沥青掺量为5.25%。底灰孔隙率高,破碎区小,呈圆形,沥青吸收量大于碎石。底灰可用作替代骨料,以增加AC-BC混合料的流量值,从而将废物转化为有价值的材料。
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引用次数: 7
A Discussion of Obser-View as a Method of Generating Data in the Construction Industry 建筑业数据生成方法中的观察者视角探讨
Pub Date : 2015-03-20 DOI: 10.9744/CED.17.1.54-58
N. Umeokafor
This study demonstrates the paradigmatic position of obser-view and argues for the incorporation of reflectivity in obser-view to foster rigorous data generation. Aimed at introducing obser-view to the construction industry as a method of generating data, this study critically examines obser-view, exploring its application to construction research. Obser-view is an emerging data collection technique developed by Kragelund in 2006, where a non-scripted interview immediately post-observation is conducted. This helps to gain a deeper understanding of the phenomenon. Although researchers adopt various strategies to ensure rigor in qualitative research, there are still concerns in relation to validity, reliability, bias and objectivity in qualitative research. However, developing strategies that will help in gaining a deeper understanding of the phenomenon in study and tackling the aforementioned challenges will help in ensuring transparency in qualitative research. A review of literature is presented, the limitations and benefits of obser-view are also presented.
本研究证明了观察者视角的范式地位,并主张将反射率纳入观察者视角以促进严谨的数据生成。本研究旨在将观察者视角引入建筑业,作为一种生成数据的方法,对观察者视角进行批判性检验,探索其在建筑研究中的应用。观察者视角是一种新兴的数据收集技术,由Kragelund于2006年开发,在观察后立即进行非脚本采访。这有助于加深对这一现象的理解。尽管研究人员采取了各种策略来确保定性研究的严谨性,但定性研究中的有效性、可靠性、偏倚和客观性仍然存在问题。然而,制定有助于更深入地理解研究中的现象和解决上述挑战的策略将有助于确保定性研究的透明度。本文对文献进行了综述,并介绍了观察者视角的局限性和优点。
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引用次数: 10
An Evaluation of Industrial Facilities Defects in Selected Industrial Estates in Lagos State, Nigeria 尼日利亚拉各斯州选定工业区工业设施缺陷的评估
Pub Date : 2014-09-01 DOI: 10.9744/CED.16.2.104-111
G. Oseghale, I. J. Ikpo
The study appraised the state of industrial facilities in selected industrial estates established between 1957 and 1981 in Lagos State by examining the nature and causes of facilities’ defects in the selected industrial estates. The buildings sampled were load bearing sandcrete block wall (1%), concrete framed structure (83%) and steel framed structure (16%). Data were sourced using structured questionnaire administered on the staff of maintenance department of 35 building materials and plastic manufacturing industries purposively selected and located in 18 industrial estates. Data obtained were analyzed using descriptive statistic. The study found the structural elements of the buildings, i.e. foundations, beams, walls, and floors satisfactory. Using the mean response analysis, the result showed that the most severe factors responsible for industrial facilities’ defects were combined effects of geo-climatic factors (2.35), combined effects of biological agencies (2.15), corrosion (1.98), and physical aggression on the facilities (1.71).
该研究通过审查选定工业区设施缺陷的性质和原因,评价了1957年至1981年在拉各斯州建立的选定工业区的工业设施状况。抽样建筑为承重砂混凝土砌块墙(1%)、混凝土框架结构(83%)和钢框架结构(16%)。数据的来源采用结构化问卷调查的方式,对35个建材和塑料制造行业的维修部门的员工进行调查,这些行业有目的地选择并位于18个工业园区。所得资料采用描述性统计进行分析。研究发现建筑物的结构元素,即地基、横梁、墙壁和楼板,均令人满意。平均响应分析结果表明,造成工业设施缺陷最严重的因素是地质气候因素的综合影响(2.35)、生物制剂的综合影响(2.15)、腐蚀(1.98)和物理侵蚀(1.71)。
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引用次数: 4
Increase on Strengths of Hot Weather Concrete by Self-Curing of Wet Porous Aggregate 湿性多孔骨料自养护对高温混凝土强度的提高
Pub Date : 2012-09-06 DOI: 10.9744/CED.14.2.92-99
V. Sampebulu
The compressive and tensile strengths of concrete made in hot weather condition decreased due to loss of mixing water caused by high evaporation. One method to overcome the problem is the use of saturated fly ash aggregate. The water content in fly ash aggregate can flow out to the hardened cement paste to continue the hydration process. This “self-curing” mechanism could produce more hydration around the surface of fly ash aggregate which sub¬sequently increases concrete strength. Experimental study has been conducted in temperature of 20o to 40o with humidity of 70% for dry curing, water curing, and nearly 100% for fog curing. Effect of self-curing could be justified as the strengths of concrete using fly ash aggregates is higher than concrete using fly ash aggregates covered with silane agent, and crushed stone aggregates. Even in high temperature, the self-curing could increase the strengths of concrete due to bond strength around the surface of each fly ash aggregates.
高温条件下混凝土的抗压强度和抗拉强度降低,主要是由于高蒸发引起的掺合水损失。解决这一问题的一种方法是使用饱和粉煤灰骨料。粉煤灰骨料中的水分可以流出到硬化的水泥浆体中,继续水化过程。这种“自固化”机制可以使粉煤灰骨料表面产生更多的水化作用,从而提高混凝土的强度。试验研究温度为200 ~ 400℃,湿度为70%,干固化、水固化、雾固化接近100%。掺加粉煤灰骨料的混凝土强度高于掺加硅烷剂的粉煤灰骨料和碎石骨料的混凝土强度,证明了自养护的效果。即使在高温下,自养护也能提高混凝土的强度,这是由于每个粉煤灰集料表面的粘结强度。
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引用次数: 8
Boundary Conditions for 2D Boussinesq-type Wave-Current Interaction Equations 二维boussinesq型波流相互作用方程的边界条件
Pub Date : 2011-03-03 DOI: 10.9744/CED.13.1.37-41
M. Mera
This research focuses on the development of a set of two-dimensional boundary conditions for specific governing equations. The governing equations are existing Boussinesqtype equations which is capable of simulating wave-current interaction. The present boundary conditions consist of for waves only case and for currents only case. To simulate wave-current interaction, the two kinds of the present boundary conditions are then combined. A numerical model based on both the existing governing equations and the present boundary conditions is applied to simulation of currents only and of wave-current interaction propagating over a basin with a submerged shoal. The results of the numerical model show that the present boundary conditions go well with the existing Boussinesq-type wave-current interaction equations.
本研究的重点是为特定的控制方程建立一组二维边界条件。控制方程为现有的能够模拟波流相互作用的Boussinesqtype方程。目前的边界条件包括只对波浪的情况和只对水流的情况。为了模拟波流相互作用,将现有的两种边界条件结合起来。基于现有控制方程和现有边界条件的数值模型仅用于模拟水流和波流相互作用在有淹没浅滩的盆地上传播。数值模型的结果表明,所提出的边界条件与已有的boussinesq型波流相互作用方程符合得很好。
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引用次数: 1
Estimation of Congestion Cost of Private Passenger Car Users in Malioboro, Yogyakarta 日惹Malioboro市私人乘用车使用者的壅塞成本估算
Pub Date : 2010-08-26 DOI: 10.9744/CED.12.2.92-97
G. Sugiyanto, S. Malkhamah, A. Munawar, H. Sutomo
Congestion is the condition when the hourly traffic demand exceeds the maximum sustainable hourly throughout of the link. The aim of this research is to estimate the congestion cost of private passenger car users in central business district along the corridor of Malioboro, Yogyakarta, Indonesia. The amount of the congestion cost is the difference between perceived and actual generalized cost in traffic jam condition. In this paper, only the congestion costs of private passenger car users are estimated, as they are expected to shift to buses. The generalized costs from origin zone i to destination zone j consist of vehicle operating cost, travel time cost, and pollution cost. This study shows that while the perceived generalized cost for private cars at Central Business District (CBD) Malioboro is IDR 3101.00 per trip, the actual generalized cost in traffic jam condition is IDR 5802.00 per trip, giving the estimation of congestion cost in CBD Malioboro for private passenger car users as IDR 2701.00 per trip.
拥塞是指每小时的交通需求超过链路每小时的最大可持续性。本研究的目的是估计印尼日惹马利奥博罗走廊中央商务区私人乘用车使用者的拥堵成本。拥堵成本的大小是在交通阻塞条件下感知到的广义成本与实际广义成本之差。在本文中,仅估计了私人乘用车用户的拥堵成本,因为他们预计会转向公共汽车。从起始区域i到目的区域j的广义成本包括车辆运行成本、行驶时间成本和污染成本。本研究表明,在马里奥博罗中央商务区(CBD),私家车的感知广义成本为3101.00印尼盾/次,而在交通拥堵情况下,私家车用户的实际广义成本为5802.00印尼盾/次,由此估算出马里奥博罗中央商务区私家车用户的拥堵成本为2701.00印尼盾/次。
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引用次数: 6
Sidoarjo Mud: A Potential Cement Replacement Material Sidoarjo泥浆:一种潜在的水泥替代材料
Pub Date : 2010-03-05 DOI: 10.9744/CED.12.1.18-22
M. Nuruddin, R. Bayuaji, M. Masilamani, T. R. Biyanto
This paper presents an experimental and analytical research conducted to study the properties of mortar when treated Sidoarjo mud was added into the mix replacing partially the cement content. The replacements were done at 0, 5, 10, 15, and 20%. Compression, tensile, porosity and Ultrasonic Pulse Velocity (UPV) tests were conducted to evaluate the effect of Sidoarjo mud in mortar. Analyses on the mud were also conducted through X-ray diffraction (XRD), X-ray Fluorescence (XRF), and scanning electron microscope with an energy dispersive X-ray analysis system (SEM-EDX). The results showed that the mud could be used as a cementitious material with optimum ordinary Portland cement (OPC) replacement at 10%.
本文对掺加Sidoarjo泥浆代替部分水泥后砂浆的性能进行了试验和分析研究。分别在0、5、10、15和20%时进行置换。通过压缩、拉伸、孔隙率和超声脉冲速度(UPV)测试来评价Sidoarjo泥浆在砂浆中的效果。通过x射线衍射(XRD)、x射线荧光(XRF)和扫描电子显微镜(SEM-EDX)对泥浆进行了分析。结果表明,该泥浆可作为胶凝材料,普通硅酸盐水泥(OPC)的最佳替代量为10%。
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引用次数: 34
Benchmarking the Performance of Construction Procurement Methods against Selection Criteria in Nigeria 根据尼日利亚的选择标准对建筑采购方法的绩效进行基准测试
Pub Date : 2009-06-25 DOI: 10.9744/CED.11.2.PP.
S. Ojo
The study developed performance indices by the widely used procurement options in Nigeria on selection criteria. The traditional mean and standardized ratio were used to form the utility coefficients. Results revealed that performance by the procurement options depended on the respondents’ categorization and cost categorization of projects. Public clients ranked the lump sum contracts more able to achieve speed for projects up to N100 million (Naira) while the private clients believe it is the design-build. As regards quality, public clients rated the Build-Own-Operate-Transfer (BOOT) system as most able to achieve the quality criterion whereas private clients rated design-build for projects up to N100 million (Naira). The study then concluded that, in the Nigerian construction industry participants do not agree on the performance of the procurement options on selection criteria.
该研究根据尼日利亚广泛使用的采购方案制定了关于选择标准的绩效指数。利用传统的均值和标准化比率构成效用系数。结果表明,采购方案的表现取决于受访者对项目的分类和成本分类。公共客户认为一次性合同更能够实现高达1亿奈拉(奈拉)的项目速度,而私人客户则认为这是设计-建造。在质量方面,公共客户认为建造-拥有-经营-转让(BOOT)系统最能达到质量标准,而私人客户认为项目的设计-建造最高可达1亿奈拉(奈拉)。该研究的结论是,尼日利亚建筑业的参与者不同意采购选择标准的执行情况。
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引用次数: 23
Wind Affected Density Current Profile in a Small Semi-Enclosed Water Body 小型半封闭水体中风对密度流剖面的影响
Pub Date : 2009-03-16 DOI: 10.9744/CED.11.1.PP.
B. Purwanto
Density current is a type of current that occurs when fluid flow enters a fluid body of different density. The density difference introduces stratification state that requires treatment in the parameterization of turbulence. Due to the geometric shape of location of this study, which is considerably small semi-enclosed water body, a Quasi-Equilibrium Turbulent Energy (QETE) model was selected. QETE was selected because of its convenient parameterization of wind induced breaking wave effect on turbulence. Two equations of the model, turbulence kinetic energy and turbulence macro length scale, were discretized and implemented into a three-dimensional hydrodynamic model. Application to density current simulation in the location of study was then carried out using the resulted model. To show how effective formulation of wind induced breaking wave effect would be, three parameterizations of turbulence were considered. They include QETE model with and without breaking wave effect boundary conditions (BC), and constant eddy viscosity turbulence parameterizations. It was clear from the simulation results that wind induced breaking-wave effect on the density current is quite significant.
密度电流是流体进入不同密度的流体体时产生的一种电流。密度差引入了湍流参数化过程中需要处理的分层状态。由于研究位置的几何形状是一个相当小的半封闭水体,因此选择了准平衡湍流能量(QETE)模型。选择QETE是因为它可以方便地参数化风致破碎波对湍流的影响。将模型的湍流动能和湍流宏观长度尺度两个方程离散化,实现为三维水动力模型。将所得模型应用于研究地点的密度电流模拟。为了说明风致破碎波效应的有效表述,考虑了湍流的三种参数化。它们包括有和没有破波效应边界条件(BC)的QETE模型,以及恒定涡流粘度湍流参数化。模拟结果表明,风致破碎波对密度流的影响是非常显著的。
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引用次数: 30
Variability Analysis of Prime Cost Sums 主要成本总和的可变性分析
Pub Date : 2008-01-01 DOI: 10.9744/CED.10.1.PP.
I. J. Ikpo
This paper investigated the variability levels of prime cost sums in building projects in order to establish the reliability of such estimates in bills of quantities. It involved a purposive sampling of forty-six executed projects in South-western Nigeria from which data on estimated and final prime cost sums as well as estimated and final contract sums were procured. Ratios interrelating the four variables were generated and their mean values determined. The mean prime cost sum overrun was found to be 41% of the estimated sums. However, a negative relationship between the prime cost sums and the final contract sums was established. Based on observed variations, models were developed to predict any of the ratios in general, and specifically, the practical prime cost range in order to effectively control overall project costs.
本文研究了建筑工程中主要成本总额的变化水平,以建立这种估算在工程量清单中的可靠性。它对尼日利亚西南部46个已执行的项目进行了有目的的抽样,从中获得了估计和最终主要费用总额以及估计和最终合同金额的数据。生成四个变量的相互关系比率,并确定其平均值。平均超支的主要成本总额占估计总额的41%。然而,主要成本总额与最终合同总额之间存在负相关关系。基于观察到的变化,开发了模型来预测一般的任何比率,特别是实际的主要成本范围,以便有效地控制整个项目成本。
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引用次数: 2
期刊
Civil Engineering Dimension
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