Showing papers in "International Journal of Sustainable Construction Engineering and Technology in 2013"
TL;DR: In this article, the suitability of stabilized laterite soils for the production of compressed earth blocks for low-cost housing construction was investigated and the results revealed that the specific gravity, bulk density, moisture content and plasticity index of both samples showed satisfactory performance.
Abstract: Materials used for the construction of walls are normally required to possess adequate strength and erosion resistance. The study investigates the suitability of stabilized laterite soils for the production of compressed earth blocks for low-cost housing construction. Soil samples for the experiment were obtained at two different locations. Sample I was obtained at a borrow pit along Gujba road in Damaturu Yobe state while Sample II was taken at a borrow pit near lake Alau in Borno sate, Nigeria. The results of the study revealed that the specific gravity, bulk density, moisture content and plasticity index of both samples showed satisfactory performance. Different cement stabilization levels of 0%, 2.5%, 5% and 7.5% were used to prepare the specimens for testing. The blocks were moulded using hand operated CINVA-Ram machine. The maximum compressive strength of 2.48N/mm2 was obtained with stabilization level of 7.5% with sample I at 28 days curing. The strength of the specimens increases with increasing cement content with an average value of 0.35N/mm2. For higher strength requirements different stabilization options can be considered.
TL;DR: In this paper, the suitability of using Recycled Concrete Aggregate (RCA) in structural concrete based on a better understanding of its strength, stiffness and durability was determined.
Abstract: The purpose of this study was to determine the suitability of using Recycled Concrete Aggregate (RCA) in structural concrete based on a better understanding of its strength, stiffness and durability. RCA was collected from three different sources: a local landfill site, a local aggregate supplier and from the demolition of two old cooling towers in Cape Town, South Africa (RSA). All RCA was prepared by crushing the demolished concrete in a laboratory crusher at University of Stellenbosch. Their physical properties were determined for comparison of different sources of RCA. RCA replacement percentages of 0%, 30% and 100% to partially replace natural aggregate (NA) in concrete were tested at different ages. Cube strength classes 30-40 MPa concrete were made to investigate the mechanical properties of RCA. Creep, shrinkage and durability properties were also tested for concrete with 0% and 30% RCA replacement of NA. It was found that RCA replacement by 30% (RCA30%) of NA does not lead to any significant difference in strength and stiffness compared to concrete containing 100% NA in concrete. RCA100% replacement does show reduced strength and stiffness, but this is not significant and can be compensated for in standard ways. Durability index tests indicated similar durability performance of concrete with reasonable quality RCA30% compared with NA100%. Increased creep was however observed for RCA30% which must be considered in structural design. Little information is available about both the mechanical and durability properties of local RCA in RSA, where this research has been performed. The authors believe this report will assist to increase the confidence of engineers to consider using RCA in structural concrete in RSA as well as abroad.
TL;DR: In this article, the authors address the measures taken to prevent or minimize the deterioration of concrete, which confronts an acidic environment and show that concrete can be made acid resistant using classical as well as novel techniques like nanotechnology.
Abstract: This review paper addresses the measures taken to prevent or minimize the deterioration of concrete, which confronts an acidic environment. Primarily, the mechanism of reaction between alkaline concrete and acid is clearly demonstrated. The mechanism of reaction clearly sets guidelines as to how the chances of this disastrous reaction should be minimized or eliminated at all. The suggested preventive measures are twofold i.e. the improvement of the basic microstructure of concrete and the provision of barriers against acids. Concrete can be made acid resistant using classical as well as novel techniques like nanotechnology. There exists an immense need that these measures are recognized and implemented by the construction industry to put a stop to huge money losses.
TL;DR: In this paper, the results of experiments evaluating the use of wood ash from bread bakery as partial replacement for ordinary Portland cement in concrete have been reported and the chemical composition of the wood ash as well as the workability and compressive strength of the concrete were determined.
Abstract: This paper reports the results of experiments evaluating the use of wood ash from bread bakery as partial replacement for ordinary Portland cement in concrete. The chemical composition of the wood ash as well as the workability and compressive strength of the concrete were determined. Wood ash was used to replace 5% - 25% by weight of the cement in concrete. Concrete with no wood ash serves as the control. The mix ratio used was 1:2:4 with water to binder ratio maintained at 0.5. The Compressive strength was determined at curing ages 3, 7, 28, 56, 90 and 120 days. The results showed that wood ash from bread bakery is a Class F fly ash since the sum of (SiO2 +Al2O3 +Fe2O3) is greater than 70%. The compressive strength of wood ash concrete increases with curing period and decreases with increasing wood ash content. There was a sharp decrease in compressive strength beyond 10% wood ash substitution. It was concluded that a maximum of 10% wood ash substitution is adequate for use in structural concrete
TL;DR: In this paper, the authors examined the effect of procurement systems on building project performance in Nigeria, with a view to assess their effect on cost and quality, and concluded that no procurement system is a do it all in that a procurement system may perform better than the other in an instant and fail in others as revealed in the findings.
Abstract: Every client at the beginning of any project aims at having value for the money spent via a quality structure delivered on time and within budget by the contractor. However, researches have shown that in most cases this aim is not met. Therefore, this study examines the effect of procurement systems on building project performance in Nigeria, with a view to assess their effect on cost and quality. The data for this study were collected with the aid of structured questionnaires which were administered to actors in the construction industry in Lagos state being the major hub of construction activities in Nigeria. The questionnaires were related to the variants of procurement systems common to the Nigerian construction industry. Data analysis was done using descriptive statistics. The result revealed that the traditional system of procurement is the most adopted option in project execution in Nigeria. Meanwhile, design and build system performs better in cost, but lag construction management system in quality achievement. The study concluded that no procurement system is a do it all in that a procurement system may perform better than the other in an instant and fail in others as revealed in the findings. The study finally recommends that consultants and other stakeholders in the construction industry and particularly those in the building sector should be up to date as to be able to suitably advise clients when it comes to building procurement, and that before choosing a procurement system the main objective and even supporting objectives should be established
TL;DR: In this paper, the authors explored the concept of sustainable construction and examined how the lean approach can impact on the sustainability practices within the construction industry using literature review to achieve the stated aim.
Abstract: The UK Government has recognised the importance of the construction industry in achieving the overall goals of sustainable development. Therefore the Government has put several policies and strategies in place to achieve a more sustainable construction. Sustainable construction is considered as the application of sustainable practices and sustainable development principles to the activities of the construction sector. Lean construction is a new production philosophy which has the potential of bringing innovative changes in the construction industry. The Lean principles focus on the minimisation of both material and process wastes which in turn contribute to sustainable construction in terms of energy consumption and improvement in health and safety etc. This study aims at exploring the concept of sustainable construction and examines how the lean approach can impact on the sustainability practices within the construction industry. The study uses literature review to achieve the stated aim. The findings revealed that the application of lean construction principle, tools and methods have direct contributions to the attainment of sustainable practices within the construction industry. However, the study postulates that the better understanding of lean concept, proper implementation and integration of lean and sustainability concepts are required for lean construction to contribute to sustainable construction.
TL;DR: In this article, the authors assessed the financial and non-financial motivational schemes, in light of their preference to construction site workers so as to assure on their vulnerability in enhancing productivity.
Abstract: The construction industry provides appreciable employment for the unskilled and semi-skilled labour considering the nature of most activities carried out on construction sites. However, the productivity of this categories of labour have trended poor overtime. This study therefore assessed the financial and non financial motivational schemes; in light of their preference to construction site workers so as to assure on their vulnerability in enhancing productivity. The data collected through the administration of questionnaires to construction site operatives were analysed using the relative importance index (RII). The research instrument was also legitimized with content validity index (CVI) for items ≥ 0.80 and cronbach alpha value, as a measure of internal consistency, ≥ 0.70. Allowances, wages stock option and bonuses are the financial motivators while delegation, independence and autonomy, facilities for transportation are the non financial motivations that are important to site workers on construction sites. Giving praises, encouragement to make contributions, free medical care, availability of relaxation centres and first aid provision are the motivation schemes that site operatives believed to enhance their productivity. This paper concludes that both financial and non financial motivational schemes are important to enhancing the productivity of operatives on construction sites. The vulnerable motivational schemes to the enhancement of productivity, as revealed in this study is recommended to the construction and subcontracting firms, foremen, clerk of works, site supervisors, site engineers and all other stakeholders in ensuring a maximum output for a unit input from site operatives.
TL;DR: In this article, an experimental investigation for improvising stabilized lateritic blocks (SLB) with coir cutting wastes from coir industry as reinforcing elements is presented. But its potential in block making is not yet satisfactorily explored.
Abstract: Tropical countries are rich in lateritic soil, a naturally available raw material for building construction. But its potential in block making is not yet satisfactorily explored. This paper focuses on an experimental investigation for improvising stabilized lateritic blocks (SLB) with coir cutting wastes from coir industry as reinforcing elements. Lateritic soil used in this study showed a higher percentage of clay content. Hence it was pre-stabilized with sand and cement. Blocks were prepared by stabilizing it further with waste fibrous additives and tested for strength and durability. Considerable improvement in strength (compressive strength @19% and tensile strength @ 9%) and durability characteristics were exhibited by the new fiber reinforced lateritic blocks (FRLB) with fiber content of 0.5%. These blocks can be successfully proposed for load bearing construction and as well as for earthquake resistant structures
TL;DR: In this article, the authors explored cost management strategies employed by contractors on building projects and also investigated the challenges that contractors encounter in managing project cost, and found that despite the growing trend to automate cost control systems, there is evidence to suggest that the traditional paper based systems of storing and managing information is widely used in the industry.
Abstract: The construction industry is a major consumer of capital resources by virtue of the magnitude, complexity and nature of the works it executes. Yet improving cost performance still remains a chronic challenge facing the construction industry worldwide. Apart from advances made by contractors to devise mechanisms to manage project cost, studies across the world reveal that construction projects are hardly completed within budget. The Zimbabwean construction industry has not been spared either. However, this background is considered unhealthy for an industry whose capital consumption is heavy and concomitant cost overruns spell disastrous financial consequences on the investor. This study explored cost management strategies employed by contractors on building projects and also investigated the challenges that contractors encounter in managing project cost. Exploratory research design was employed making use of both questionnaires and interviews to collect data from selected contractors registered under category A, B and C of the Construction Industry Federation of Zimbabwe (CIFOZ). The study observed that in the majority of cases, contractors’ efforts to manage projects costs are centred on management of project resources. Additionally, monthly cost reports, variance management, project budgets and cash flow forecasting are among the other strategies. However, in spite of the growing trend to automate cost control systems, there is evidence to suggest that the traditional paper based systems of storing and managing information is widely used in the industry. Contrary to having cost management systems in place, contractors admit experiencing cost overruns on their projects. These cost overruns are attributable to organizational related challenges, shortage of skilled personnel, and unavailability of some building materials on the local market, variations and deficiency in cost control systems
TL;DR: In this paper, a set of measures to reduce water consumption and enable a more efficient use of this resource in residential buildings are presented, focusing on user awareness campaigns, systems of rainwater and grey water recycling, the use of more efficient devices and reduction of leaks.
Abstract: Water is the most important resource to all life on our planet. The impact that buildings have on the consumption of this resource throughout their life cycle (planning, construction, operation and deconstruction) but mainly during the operation phase, has resulted in very high and unsustainable consumption patterns. Sustainable development, while a long-term goal, requires that the preservation of natural resources becomes a central point of any project strategy. Water is of vital importance to human life, it should be preserved to ensure its availability for a long period of time. However, little concern has been given to the importance of introducing a selection of more efficient solutions to save water in buildings and consequently increase sustainability in the construction sector. In this context it is on the design phase that the main resource saving water measures should be considered. Research on saving water involves an analysis of quantitative and qualitative measures and their adaptation to different contexts. Nowadays there are systems of voluntary certification of sustainable construction, which can help the design phase to achieve sustainability. This paper discusses a set of measures to reduce water consumption and enable a more efficient use of this resource in residential buildings. The measures presented are focused on user awareness campaigns, systems of rainwater and grey water recycling, the use of more efficient devices and reduction of leaks. The measures are analyzed and compared taking into account the consumption patterns for each device both inside and outside a domestic building and its effective reduction in water consumption
TL;DR: In this article, the authors examined the relative importance of the project success criteria in the Nigerian construction industry and determined the correlation among the project satisfaction criteria and concluded that there are four major components of construction project success in Nigeria- user-related factors, professionals' factors, organisational factors and other minor factors.
Abstract: This paper examined the relative importance of the project success criteria in the Nigerian construction industry. It also determined the correlation among the project success criteria. Based on the literatures reviewed, the study proposed a framework for measuring project success in the construction industry. The respondents for the study were the government, private clients, consultants and contractors. Three hundred copies of questionnaires were distributed to capture data on the subject, but only 86 were returned and used for the study. The paper captured respondents that are resident in Lagos state, Nigeria and chosen by convenience from selected organizations used for the study. The data were analysed with SPSS 16 through the use of frequencies, mean scores, factor analysis and correlation. Factor analysis was employed because the mean scores showed that all the project success criteria were at least important. Nine principal components were finally merged into 4 through the factor analysis using the Varimax rotation with Keiser normalization. The study found out that all the project success criteria were important but their level of importance differs according to the factor analysis carried out. Therefore, it was concluded that there are four major components of construction project success in Nigeria- user-related factors, professionals’ factors, organisational factors and other minor factors. The minor factors were found to be related to both organizations and projects but were not highly rated by respondents for determining construction project success. The study also concludes that project success criteria goes beyond meeting cost, time and quality target, it includes users’ satisfaction, professionals’ fulfilment and achievement of organizational goals. The recommendation of the study was that for construction projects to be successful, attention must be paid to users’ related factors, professionals’ factors and organizations’ factors.
TL;DR: In this paper, the authors used ANOVA and regression analysis on the building elements cost and time were used to establish models to predict the average final cost of each building element, and the average overall final cost overrun due to variation.
Abstract: A number of research studies have been carried out on the causes and effects of variation on construction project delivery, thereby taking for granted the susceptibility of building elements to variations. This formed the basis of this paper with a view to assessing the cost and time implications of the susceptibility of each building element to variation during construction process in Nigeria. Archival record comprises contract drawings, original bill of quantities, addendum and reduction bill of quantities, and minutes of site meetings among others were used to extract data relating to initial cost, final construction cost, estimated period, final completion period of each building element attributed to variations. The data obtained were analyzed using statistical methods of average, percentage, regression analysis, and analysis of variance (ANOVA). The study identified the building elements having greater than 20% of cost overrun due to variation as earthwork and fillings, frame, windows and external doors, fittings and furnishings, water installation, and external services. The study further identified the building elements having greater than 25% time overrun due to variation as earthwork and fillings, block work (at substructure), upper floors, external walls, wall finishing among others. The results of ANOVA and regression analysis on the building elements cost and time were used to establish models. Thus, the established models are: AFC= 981690 + 1.033AIC; and AFCO= 608390.865 +1.310AIC to predict the average final cost of each building element, and the average final cost overrun of each building element due to variation respectively, where AFC= Average Final Cost, AIC= Average Initial Cost, and AFCO= Average Final Cost Overrun. Also, the study established the model: Y = 1.379(X) – 0.251 for predicting the average actual completion period of each building element, where Y= Average Actual Completion Period, and X= Average Estimated Period (week). The study provides information that enables the clients, consultants/professionals, and other construction stakeholders to understand the building elements that demands specific attention in terms of cost and time implications of variations. The study also provides building clients a foreknowledge of cost variance that is likely to occur on each building element during construction process
TL;DR: In this paper, a new membrane for microbial fuel cell (MFC) was fabricated using sulfonated polyether ether ketone (SPEEK) and Cloisite 15A®.
Abstract: Ion exchange membranes have been used in microbial fuel cell (MFC) because it can prevent high oxygen permeability and the migration of substrate instead of protons from one chamber to another. Despite all these advantages the usage of this type of membrane suffers several operational problems such as high dissolve oxygen permeability, adverse deformation and proton conductivity which can affect the MFC performance. In order to overcome this problem, new membrane for microbial fuel cell system was fabricated using sulfonated polyether ether ketone (SPEEK) and Cloisite 15A®. The membranes were characterized based on their electrochemical and physical properties. The characteristics of the SPEEK nanocomposite membranes were then compared with the unmodified SPEEK membrane and the commercially available Nafion117 membrane. Based on the result, SPEEK/Cloisite 15A® contributed high energy generated across the load compare to SPEEK without additive and Nafion 117. The incorporation of Cloisite 15A® improved the water uptake from 56 to 78.2 wt% and reduced the dissolve oxygen permeability of the membrane from 1.5 to 0.7 cm/s but the tensile strength behaviour was reduced from 11.2 to 7.5 MPa.
TL;DR: In this paper, a sustainable construction strategy for residential buildings in Nagpur, India has been developed, which includes conservation of soil, energy, resources, material and water, and the amount of excavated soil and its reutilization on site.
Abstract: Developing cities in India like Nagpur are growing exponentially in population due to industrialization. The ever increasing demand of the natural resources leads to depletion of limited resources and also affects local environment in terms of increasing pollution emissions especially carbon emission. With recourse to composite climatic condition (Nagpur, India) the sustainable construction strategy is developed in the present paper. The developed strategy includes conservation of soil, energy, resources, material and water. It provides a systematic approach towards sustainability of building through quantification of energy consumption. Analysis of conventional and nonconventional material and technology on cost, energy -consumption and carbon emission parameters helps in highlighting suitable options for sustainable construction. Strategy is validated through a case study of new construction of the residential buildings for enhanced environmental performance. The amount of excavated soil and its reutilization on site is taken into consideration. Locally available sustainable construction materials are compared for material cost, and embodied energy for selection of appropriate construction material. In order to conserve the ground water various options for the low flow devices, roof top rainwater harvesting and gray water recycling and reuse are suggested. Application of sustainable construction strategy to case study building revealed that 97% of natural soil is conserved through backfilling. Estimated carbon emission reduction due to recommended construction materials (sustainable bricks, cement, and steel) with respect to conventional options is of the order of 60%. Recommended water conservation options resulted in 57% reduction in ground water demand. However suggested sustainable construction strategy options estimated in increase in project cost by 13% whose effect can subsequently be reduced over the design life span computations. The developed strategy can further be applied to the larger residential township areas with varying building types for conserving the natural resources as well as reducing the impact of environmental pollution.
TL;DR: In this article, the contributions made by researchers on microsurfacing as a tool for pavement maintenance and repair are discussed, focusing on the contributions of researchers on Microsurfacing, which is a preventive maintenance technique (preventative maintenance strategy aims at producing the most cost effective improvements in pavement quality and life) involving three to six millimeter sized bitumen aggregate treated with a special emulsion.
Abstract: With the development of infrastructure, in rapidly developing modern era, frequent maintenance of existing infrastructure, especially roads is of prime importance. Microsurfacing is a preventive maintenance technique (preventative maintenance strategy aims at producing the most cost-effective improvements in pavement quality and life) involving three to six millimeter sized bitumen aggregate treated with a special emulsion. The layer is neatly laid down on road section requiring maintenance. This paper aims at focusing on the contributions made by researchers on Microsurfacing as a tool for pavement maintenance and repair. Although the technique is finding its place in Indian sub-continents little late, but nevertheless it is universally considered as an inevitable tool as far as preventive pavement maintenance is concerned and should be used to extend life of the underlying pavement
TL;DR: In this paper, a mathematical model to predict the permeability of water transport in concrete has been established, the model is to monitor the rate of water transfer in concrete structure, the process of this water transport is based on the constituent in the mixture of concrete.
Abstract: Mathematical model to predict the permeability of water transport in concrete has been established, the model is to monitor the rate of water transport in concrete structure. The process of this water transport is based on the constituent in the mixture of concrete. Permeability established a relation on the influence of the micropores on the constituent that made of concrete, the method of concrete placement determine the rate of permeability deposition in concrete structure, permeability establishment are under the influence of the micropore between the constituent through the cement paste, coarse aggregate fine sand and water, the micropore between this material as a component of concrete are known as porosity and void ratio in the concrete structure, the influence of the permeability coefficient determine the rate of water transport in concrete, considering the variables in the system, mathematical model were established to monitor the rate of water passing through concrete and also determine the rate of permeability coefficient on concrete structure.
TL;DR: In this article, the construction management function of the quantity surveyor in line with the principle of lean methodology (Just-In-Time) was investigated by exploring the cost management function, to investigate the current practice of cost management by quantity surveying firms.
Abstract: The Construction industry in Nigeria is made up of a wide variety of activities which include the provision of professional and technical services to clients in the built environment. Despite the provision of these services to a large number of clients worldwide, the construction industry is still awash by the chronic problems of low productivity, insufficient quality, time over-runs, and poor safety, which hinder customer delivered value. The Just-In-Time phenomenon is a characteristic of lean production systems which operate with very little “fat” (e.g. excess inventory extra workers, wasted space).This study aimed at assessing the construction management function of the quantity surveyor in line with the principle of lean methodology (Just-In-Time). This was achieved by exploring the cost management function of the quantity surveyor, to investigate the current practice of cost management by quantity surveying firms. Data for the study were sourced primarily with the use of questionnaire and the subsequent data analysis, which employed the use of descriptive analysis of presenting the data as obtained on tables during the field survey and attempts a rudimentary establishment of patterns using percentages. The study concluded amongst others, that: all activities involved in the cost management function of the quantity surveyor are important, and value adding, corresponding to conversion activities in line with the Just-In-time/lean methodology
TL;DR: In this article, the effect of amorphous silica residue (ASR) in the production of concrete was investigated, and the results of the compressive strength test for 5-30% replacement of OPC with AMR ranges from 12.78-38.04N/mm 2.
Abstract: In this research work, the effect of amorphous silica residue (ASR) in the production of concrete was investigated. A mix proportion of 1:1.9:3.9 with water/cement ratio of 0.48 was used. The percentage replacement of Ordinary Portland Cement (OPC) with amorphous silica residue was 0%, 5%, 10%, 20% and 30%. Concrete cubes of 150mm x 150mm x 150mm and concrete beams of 150mm x 150mm x 600mm of OPC/ASR were cast and cured at 3, 7, 28, 60 and 90 days. At the end of each hydration period, the three concrete cube and beams for each hydration period were crushed and their average compressive and flexural strength recorded. A total of seventy five (75) concrete cubes and seventy five (75) concrete beams were cast. The result of the compressive strength test for 5-30% replacement of cement with amorphous silica residue ranges from 12.78-38.16N/mm 2 while the control test (0% replacement) ranges from 10.86-26.04N/mm 2 . The result of the flexural strength test for the same replacement level of cement with amorphous silica residue ranges from 2.29-11.69N/mm 2 while the control test ranges from 2.14 – 7.80N/mm 2 . The initial setting time of OPC/ASR for 5-30% replacement level of cement with amorphous silica residue ranges from 37-53mins while the final setting time ranges from 408-573mins. The initial and final setting time of the control test is 58mins and 580mins respectively. Relevant literature has been cited to justify this research work. The main objective of this work is to determine the effect of amorphous silica residue on the setting time, compressive strength and flexural strength of concrete produced with it.
TL;DR: The features of the system provide a collaborative environment and reduce repetitive works commonly occurring in manual processes and how the system framework enhances collaboration in the certification process is described.
Abstract: The built environment is moving towards sustainable development and the number of green buildings increased worldwide in recent years. Green buildings are environmentally, socially and economically desirable; however the certification of green buildings is often expensive and labor-intensive. The document preparation and review process for green building certification is iterative in nature and requires the collaboration of many project participants, certification organizations and third party engineering consultants. This paper aims at developing a system framework that can assist the green building certification process. Different certification standards have been studied and their scope and credit calculation were compared to understand the requirements of the system framework. Based on the study, the required features were designed as follows, (1) role-based access control, (2) document manager and related document discovery, (3) workflow manager, (4) credit manager, and (5) knowledge manager. The features of the system provide a collaborative environment and reduce repetitive works commonly occurring in manual processes. The features of the system framework are discussed and illustrated considering the Hong Kong BEAM Plus standard. This paper also describes how the system framework enhances collaboration in the certification process