Performance-Based Approach for Deciding the Age of New Concrete for Thin Epoxy Overlay Application

Author(s):  
Upul Attanayake ◽  
Abul Fazal Mazumder

A thin epoxy overlay application is a capital preventive maintenance activity. Epoxy overlays reduce the rate of chloride ion ingress and extend bridge deck service life. Highway agency policies and manufacturer specifications require maintaining a 28-day curing period (7-day wet and 21-day dry curing) before the application of an epoxy overlay on bridge decks requiring new concrete for patches and repairs. Consequently, the contractors wait for 28 days to apply an epoxy overlay. Delaying application time increases project completion time and the cost of construction and mobility. The suitability of new concrete to receive epoxy overlays and the performance of overlays depend on several parameters including concrete strength, moisture, and tendency to crack. Such parameters depend on concrete mixture ingredients and wet and dry curing periods. This paper presents a performance-based procedure for evaluating the possibility of reducing the 28-day waiting period for a thin epoxy overlay application on new concrete. An experimental program was developed and executed to evaluate the impact of epoxy overlay application parameters and overlay performance using a tensile bond pull-off strength test. The results support developing a performance-based procedure for deciding on the suitable age of new concrete to receive a thin epoxy overlay. The pull-off bond strength of epoxy overlays applied at 7, 14, and 21 days, following a 7-day moist curing, shows the possibility of applying an epoxy overlay before the end of the 28-day curing period stipulated in the current specifications.

Author(s):  
Abul Fazal Mazumder ◽  
Upul Attanayake ◽  
Neal S. Berke

Healer sealer application is one of the capital schedule maintenance (CSM) activities for enhancing concrete bridge deck durability and extending the service life. A healer sealer is expected to seal the cracks and reduce the rate of chloride ion ingress. Highway agency policies and manufacturer specifications require maintaining a total of 28-day curing period (7-day wet and 21-day dry curing) before the application of a healer sealer on bridge decks with new concrete in patches and repairs. Consequently, the contractors have to wait for 28 days to apply a healer sealer. Delaying application time increases project completion time and cost of construction and mobility. This paper presents a performance-based approach for evaluating the possibility of reducing the 28-day waiting period for healer sealer application on bridge decks with new concrete. An experimental program was developed and executed to evaluate the impact of healer sealer application parameters on crack sealing ability. A healer sealer was applied at 14, 21, and 28 days of concrete age. The treated surface was ponded with 3% NaCl. The performance of the treated concrete was evaluated using the acid-soluble chloride content test. The results showed the possibility of applying a sealer before the end of the 28-day curing period stipulated in the current specifications. The performance-based approach presented in this paper can be used to identify the age of concrete for healer sealer application.


Author(s):  
Z. H Ishaq

Construction projects are prone to a number of risks due to their complexity, dynamic nature, capital intensive nature and involvement of many stakeholders. These risks if left unmanaged will negatively influence the completion cost and other primary objectives of construction projects. Numerous studies have been conducted globally to determine the potential risks that negatively impacts construction projects; however, the risks aren’t alike across all the regions and the potential degree of impact may changes with time. This study assessed the impact of risk factors on completion cost of construction projects in Nigeria. Data was collected using structured questionnaires administered to 192 construction practitioners using convenience sampling technique. Descriptive statistics (mean and standard deviation) were used to analyse the data. The study found ‘inadequate cost estimate’ (MS = 4.39), ‘risk incurred due to bribery and corruption’ (4.30), ‘increase in prices of materials’ (4.25), ‘increase in cost of labour’’ (4.11), ‘poor cash flow management’ (4.04) ‘mistakes/errors in design’ (4.04) and ‘mistakes during construction’ to be the topmost risk factors that impact on project completion cost. The study concludes that ‘economic’, ‘financial’ and ‘contract administration and project management’ related factors group are those with high impact on project completion cost.


2020 ◽  
pp. 136943322097477
Author(s):  
Yijie Huang ◽  
Jianzhuang Xiao ◽  
Li Qin ◽  
Peng Li

An experimental program was undertaken to study the mechanical behaviors of glass fiber-reinforced polymer (GFRP) tube confined recycled aggregate concrete with sea sand (GRACSS) under the axial compression. Two different parameters were mainly considered: recycled coarse aggregates (RCA) replacement percentage (0, 100%) and type of sand (sea sand, river sand). Typical influences of RCA and sea sand on the strength, the deformation and the load–deformation curve of GRACSS were investigated. The test results showed that the failure pattern of GRACSS was similar to that of GFRP tube confined ordinary concrete (GCOC). The strength of GRACSS decreased with an increasing RCA replacement percentage, while sea sand could reduce the negative effect of RCA. It is also found that the peak deformation of GRACSS increased with the increasing RCA replacement percentage whereas with decreasing sea sand chloride ion (Cl–) content. The stiffness of the specimen was obviously influenced by the concrete type. Research findings indicated that the axial load-deformation curve of GRACSS can be divided into elastic-plastic and hardening stages. An analytical expression was proposed to calculate the load-deformation curve of GRACSS. Finally, the finite element method (FEM) was applied to study the effects of outer tube thickness, concrete strength, RCA replacement percentage and Cl– content in sea sand on the mechanical behaviors (strength and deformation) of GRACSS.


ILR Review ◽  
1982 ◽  
Vol 35 (3) ◽  
pp. 319-329 ◽  
Author(s):  
Frank Reid

This study describes and analyzes an experimental program established in Canada in 1977 under which layoffs were avoided in twenty-four firms by reducing the hours worked of all employees and taking advantage of a temporary modification of unemployment insurance legislation that allowed workers to receive UI benefits for the day or so each week that they no longer worked. Employees generally favored the plan because, in the typical case of a 20 percent work reduction, they received an extra day of leisure per week while experiencing only a 5 percent reduction in after-tax income. Most employers also favored the plan because they avoided several costs of layoffs, such as the cost of hiring and training replacements for laid-off workers who do not respond to recall. For various reasons the federal government did not continue the program when the experiment ended in 1979, but in January 1982 the government again implemented the program on a temporary basis. The author argues that UI-assisted worksharing is more efficient and more equitable because it can greatly reduce the distributional inequities of unemployment.


2020 ◽  
Vol 25 (2) ◽  
pp. 166
Author(s):  
Eko Marsudi Utomo ◽  
Mochamad Agung Wibowo ◽  
Sriyana Sriyana

Based on the initial plan from the contract of the Rehabilitation Klambu Kiri’s Project, main channel's work was carried out continously by an open and closed system using the kistdam method. However by the time of execution work, the stakeholders wanted the work in the main channel to be carried out based on cropping pattern, where there a drying period and a drainage period. In this case, flow area and bottom structure of the channel can only be worked during the drying period lasting three months. To be able to determine the impact of these change, a duration calculation is carried out from project's data which are internal's BQ, initial plan's resources, and the relations between activities using Microsoft Project on the flow section structure which be worked in drying period of 2017. The normal duration obtained from analysis is 203 days. It was exceeded time of drying period and possibly could have an impact on the overall project completion schedule resulting in delays, defaults and even termination of contracts. Therefore, it is necessary to have an accelerate strategy of the work on the flow section structure to be completed within a predetermined time. In this study, the acceleration strategy was carried out using crashing analysis in the critical activities from normal duration using Microsoft Project. The crashing method was carried out in stages from the crashing simulation of 30 days, 60 days, to 120 days so that obtained the duration of acceleration was 83 days. The cost component of acceleration is calculated by choosing the lowest cost from the alternatives of increasing work hours (overtime) or by adding resources. From the simulation results, the crash cost to complete the acceleration work is Rp. 1.298.307.591,- or about 2,05% of direct cost, so the efficiency is Rp. 9.692.409,- from normal duration


2021 ◽  
Vol 2021 (23) ◽  
pp. 8-19
Author(s):  
Artem Bezuglіy ◽  
◽  
Ihor Hresko ◽  
Olena Belska ◽  
Yuliya Bibyk ◽  
...  

Introduction. As the foreign experience of many countries of the world shows, a fairly common practice in determination of the road works cost is the use of works cost evaluation method with the help of designed and constructed objects on the roads. Actually, for the preliminary evaluation of the road works cost on the early stages of design in Ukraine the method of evaluation of objects-analogues by using a comparative approach becomes more common. The comparative approach is one of the main scientific methods, which by comparison determines common and different characteristics, parameters in the process of objects studying, etc.Problem Statement. The research of the construction industry problems, in particular the determination of construction and designing works cost became the main topic of works of many scientists, in particular Berkuta A. V., Khaikin G. M., Kolesnikov O. V. and others. In general, the scientists raised questions of the construction works cost at different stages of project development, because the obtaining of such information gives an opportunity to perform economic evaluation of new projects and determine the effectiveness of the design solutions. The need for rapid cost information obtaining at the initial stages of project development is also particularly important, as this information serves as a benchmark for cost projections for the implementation of new objects. These factors are a prerequisite for the need to create a database of objects-analogues.Scientific justification of any process has a great importance in selection of the most effective ways for its realization. Economic science is facing new targets and objectives, the solution of which contributes to its development. An important task in this case is to implement and maintain the achievements of scientific and technological progress of the investment process. When developing a new investment project of new construction or reconstruction of a motor road a significant load falls on the pre- Збірник наукових праць «ДОРОГИ І МОСТИ» www.dorogimosti.org.uaISSN 2524-0994. Dorogi i mosti, 2021. Issue 23ЕКОНОМІКА. МЕНЕДЖМЕНТ19investment stage, which lays the foundation for the future facility and the success of its implementation. The pre-investment stage includes the development and approval of project documentation, which contains a feasibility study (drawings, explanation reports) and other needed documents. This stage is extremely important, because the development of the project is an important component in the overall implementation of the object and connects science with the construction process. The efficiency of future investments, the estimated cost of construction of the investment object and the terms of its implementation depend on the quality of the technological justification and the level of design solutions.The information and analytical system on the designed and constructed objects-analogues allows the customer to perform a preliminary evaluation of the road works cost at the early stages of designing. It is the study of the basic parameters and conditions that are essential prior to the beginning of the construction and that precede the implementation of construction solutions and identify a system of key indicators (economical, structural, technical) to compare the built object with the object, which is under construction. Indicators and criteria defined for the comparison of road objects, which are designed with the completed objects, make it possible to receive extended information and analyze it in the environment of the information and analytical system, which is based on the method of analog determination of the cost of road objects.Purpose. The purpose of this study is to analyze the information and analytical system for constructed and designed objects - analogues on public roads for prompt obtaining the information on technical, structural, economic indicators for preliminary evaluation by the customer of works cost within the documentation at early stages of designing.Materials and methods. The necessity of considering this topic is based on the application of one of the priority approaches to the cost evaluation - comparative, which determines the cost of the evaluated object by taking into account availability or lack of certain characteristics by this object in comparison with similar objects. The implementation of such comparative approach is possible when the needed information is available on the indicators of objects-analogous that are compared with the designed object. The comparative approach of evaluation involves carrying out a wide range of procedures with the validation of features (elements) of the comparison of the evaluated object and the objects-analogues; determination of quantitative dependencies of the parameters used for evaluation, adjustment of values of the investigated indicators and determination of summary results. During comparative evaluation of the objects a very important aspect is the validation of values (parameters) by which the comparison of road works objects is carried out.Results. Determination and analysis of the main criteria that affect the cost of construction and data collection on designed and constructed facilities on public roads, design documentation of which is agreed and approved in the prescribed manner, became the basis for creating of information and analytical system. Information and analytical system use makes it possible to determine the preliminary road works cost at the pre-investment stage of the project. This information shows the investor an approximate amount of investment required for road works on public roads and transport facilities on them.Conclusions. The method of comparative approach is one of the possible in the process of formation of the road works market cost as by both the customer and the contractor. The basis of the information and analytical system is the method of analog comparison based on a comparative approach. The comparative approach is applied by the analysis and comparison of technical and economic indicators of objects-analogues (identical or similar objects of construction), and therefore its application allows to receive real road works market cost. The use of this method is effective for determination of value of the object at the early stages of development of investment projects (feasibility study developed on the basis of initial data for linear objects of engineering and transport infrastructure, which require detailed rationale of relevant decisions and determination of options and feasibility of the object construction).Keywords:information and analytical system, road works, object - analogue


2011 ◽  
Vol 189-193 ◽  
pp. 1532-1537
Author(s):  
Wei Lo ◽  
Yih Tzoo Chen

Many techniques have been developed to analyze the time impact and the costs caused by the disruptions of the project works. However, most were limited on the delay of the critical path and the overall project completion date. In recent years, although more attention has been drawn on the impact of the float loss on the overall project cost, not a single research result has been widely accepted and recognized. This study aims to fill this gap. This research firstly introduces a resource-integrated genetic algorithms (G.A.) model, which will be used to develop an optimal schedule including the timing and quantity for each type of resource required to complete each individual activity. Secondly, by using a case study this research intends to identify the impact of float loss on overall project cost through comparing the as-planned optimal schedule with an after-impacted schedule. Based on the research results this research has identified that the relationship between the float loss and project cost can be expressed as a step function and the time span of total float can be divided into and cost-related float and cost-unrelated float, termed as optimal float, in which the consumption of float will not cause the delay of the project completion date, nor the increase of project cost. The findings refute the traditional concept that the total float belongs to neither the owner nor the contractor, and suggest that the utilization float is free only within the optimal float and the float apportionment will never be reasonable unless the cost of float floss has been taken into consideration.


In today’s scenario, construction equipment plants are essential for any construction projects and are also important for rapid progress and improvement in the quality of work. Breakdown and less productivity of equipment can increased the cost of construction project. Hence it is important that attempts to be made to increase the productivity of equipment. Earlier research has often addressed this fact, but it has rarely explained the causes and consequences of downtime. Thus this research paper highlights various causes of downtime of RMC plant and Transit Mixer. Also the downtime cost of RMC plant and Transit Mixer (TM) is determined by using mathematical model, COX Model and NUNALLY Model. These models are used to identify the downtime cost of equipment where COX Model gives the value by only taking into account of failure machine and not considering the impact, while the NUNALLY Model gives higher value due to considering the overall impact of failure machine on work.


CERUCUK ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 105
Author(s):  
Akhmad Fitriadi

Overpass project development Marabahan is a CSR (Corporate Social Responsibility) from PT. Talenta Bumi, namely making public care facilities for the security and facilitate road transport and to improve the welfare of society .This project Overpass consists of main bridge prestressed concrete girders with spans of 30 m and bridges using slab pile construction with a total length of 200 m. This study aims to determine the calculation method of the analysis of in situ casts gradually and to determine the method of implementation of the phased-situ cast on Marabahan Overpass project.Analysis of cast insitu method stages in the project completion Overpass PT. Marabahan Earth's talents will be obtained security calculations on the structure of the Overpass. Foundry work first is casting with cast in situ on the crown, after it's done casting method cast in situ stages at the slab to be divided into two stages, namely the first layer 20 cm (half slab) and the second layer 15 cm (top slab) using scaffolding as a scaffold and job formwork with main reinforcement ɸut 22-150 which gradually cast directly on the ground with the popularity chart Fc validation test cylinder '30 MPa and graphs coefficient of concrete strength PBI age 71. For loading on board, the work scaffolding (scaffolding) at the time of cast insitu gradually in the field wearing a scaffold with a heavy load capacity (heavy duty) has a maximum load of 675 kg/bay or 0.675 tons/m2, and using strong wooden scaffolding with wood class III based voltage PKKI 1961 timber permit.Based on the analysis results of calculations using the method of cast insitu gradually, by doing a test trial error with conditional on calculation of security moment of the plan should be greater than the moment of ultimate, then casting the first layer half slab in getting workable with the concrete less than one day the Fc '5 MPa and to stage a second layer using a comparison chart coefficient PBI age compressive strength, obtained Fc' 9.57 MPa to 1.5 days workmanship of the concrete casting. With the trial based on the test results of the concrete age, can accelerate and cut time jobs and can save the cost of the work, such as the cost of the use of formwork and scaffolding usage. suggestednecessary to test the concrete test cylinders for 1 day, 2 days, 3 days, etc,so that getting the maximum test.


2021 ◽  
Author(s):  
Theodoros Chrysanidis ◽  
Nikolaos Alamanis ◽  
Grigorios Papageorgiou ◽  
Georgia Kaouri

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