Written on Friday, January 24, 2014 by Jose Sanchez Marquez
The following information was the result of a Project conducted at Concordia University, Montreál, Canada called
IMPROVEMENT OF CONVENTIONAL DELIVERY SYSTEMS BASED ON LEAN CONSTRUCTION PHILOSOPHY
by,Bibiana Toro, Aquiles Chrsitopher, Jose Sanchez Marquez, Mohemmed Albutainy, Elsadek Halawa, Sorror Zamani, Saba Mohammadi, submitted for the Master Course BLDG 6571 Project Management (Fall 2013).
The main idea of this project was identify the differences between traditional construction system and new emerging philosophies such as Lean Construction. Althought the principles follows by Lean are similar to Integrated Porject Delivery (IPD) system, both believe in,
The Earlier the planning begins, the less costly the project will be and more likely that the project will meet it's goals.
Although, the IPD system is fully committed with Green building considering also the operating and maintenance costs of the building over its lifetime and sustainable development.
In this post you're going to see an small what's waste definition and in simple words the main differences betweeen the conventional and Lean. Finally, the strategies that Lean follows in order to achieve its goals. (Note: the all project is not presented here, only some parts developed by me and Bibiana Toro. However the final conclusion and references are fully shared).
In order to start it was first neccesary to identify:
WHAT'S WASTE ?
Activities can be classified according to its impact on the project value as follows: (Ningappa, 2011)
· Value adding activities: any conversion activity that is very crucial to improve any process.
· Non-adding value activities: this can be divided in to two types:
- Contributory Activities: some time called the supportive activities. It is the activities that do not add value but it is needed to finish the work (transportation, preparation of the work, inspection, etc.)
- Delay activities: some time called waste activities. It is the activities that do not add value and it is not needed to finish the work (waiting, idle, and piling up material double handling, etc.)
The differences between the two approaches are explained and presented, in the following sub-groups, Main Concept, Initiation, Project Planning, Productivity, Motivation and Contract agreements.
The conventional approach basically focuses on two targets, finishing on time and within the budget in order to satisfy reach client satisfaction. Once these targets are reached any kind of improvement in the way do things, is overlook and consider as too complicated to implement.
Lean Construction instead, focuses on maximize or improve the production value in each activity and minimize waste that, it is consider as a non-add-value activity or flow activity (waiting, long inspection, inside transportation) in order to meet or exceed client satisfaction (Lincoln H. Forbes, 2011).
Generally, in the conventional approach the personnel are integrated into the project only once their work or opinions are required (contractor, subcontractor, suppliers). This kind of condition generally produces a slowdown productivity in the first days, weeks or even months for the new subcontractor/contractor/supplier meanwhile identified how is going to work and if the previous work done is going to affect the performance of its own work.
Lean construction characterized by an early recruitment of leaders in crucial activities and fields for the project completion (architects, surveyors, civil, structural and building services engineers, etc.). Based on their different range of expertise and due to they are more familiar with their work and crew productivity for every activity is possible to generate a better Project Planning, Project Scheduling and Project Baseline guided by the Project Manager and supervised by the different stakeholders.
It is clear that the success of any project depend on the use of knowledge, skills, tools and techniques developed for the constructions industry until today. Techniques as, Project Planning use to establish the framework of the project where sequence and inter-dependence on each activity (WBS) is define; Project Scheduling use to estimate the critical Path (project duration); and the Project Baseline mainly use to allocate resources to individual packages are generally estimate by a group of professional (project stakeholders) representatives of a project or functional organization.
Lean construction use a technique known as “Last Planner”, the concept relies on empowering the foreman and crew leaders to decide on the specific tasks to be done in the following weeks, working as unit they can provides ideas based on their different range of expertise as they are closest to the work and are more familiar with its relation to each person’s capabilities (Lincoln et al., 2013).
Commonly Lean projects use a 3D modeling software known as “Building Information Modeling (BIM)” that allows combine all the information in just one model. Since subcontractors to A/E can updated information before beginning construction, with opportunities to estimate materials quantities, analyze better construction alternatives, estimate waste, to finally help to develop best practices and avoid conflict or 'clash detection' whereby the computer model visually highlights to the team where parts of the building may wrongly intersect.
Lean construction uses production management techniques which allow a better operation of resources, labor and materials. Productivity is optimized at project level due to processes are actively monitoring and daily planning, making possible to identify specific actions and good practices that would help achieve more efficient construction. In other words, it emphasizes having work flow between crews without interruption (Lincoln et al., 2013) and it focus less on the point (craft speed) and more on throughput (eliminate down time).
Nowadays, is common to believe that, keeping an intense pressure for production on every activity because reducing the cost and duration of each step is the key to improvement (Rogers, 2013). Although, productivity is reduced by attempting only to optimize just one or few activities and not the overall project, avoiding the interaction between parties or subcontractors generating the self-interested thinking and tend to proceed as quickly as possible, resulting in work that interrupts the sequence of upstream tasks (Lincoln et al., 2013) leading to low quality practices with high percentage of waste or non-productive activities.
Lean recognizes that a project is a network of commitments, trust and be trusted is fundamental. Although construction industry is most likely to happen in a temporary location and on a given time, work and think as a team is a big effort that requires continuous motivation and constant monitoring including new and old staff in order to achieve a common objective. Additionally, lean philosophy embraces the figure of the “Facilitator” responsible of maintaining non-adversarial attitudes through ongoing workshops (Lincoln et al., 2013).
Lean contracts are based on relational aspects, in it the team interest have equal or greater weight than the legal agreement, financial benefits and losses are apportioned between the parties, meanwhile conventional contracts include penalties for under performance or non-performance by each party in a project.
Additionally, provides little incentive for subcontractors to collaborate or cooperate with each other, focusing only on finish their portion on time and within budget, commonly designers are more focused on the form of the finished product than in the method of how it gets produced.
Lean enables the parties to work together, share ideas and knowledge for mutual benefits. Conventional contracts also rewarding some of the parties for optimizing their performance at the expense of others due to, there is not a clear-cut responsibility to the other parties or subcontractor. Meanwhile lean focuses on reduce risk instead of shifting it to others, and to achieve a successful outcome beyond their self-interest creating an atmosphere of goodwill that helps to resolve situations where one party fails. (Lincoln H. Forbes, 2011). The following table summarize the differences between the Conventional Construction and the Lean Construction approach.
Table 9 Differences between Conventional Construction and Lean Construction
Lean construction is a new delivery method based in the lean philosophy developed from the lean manufacturing process. This method introduces a new procedure based on measure of cycle-time or work flow; focusing on the completion of planned work per week and measuring the Percent Plan Complete (PPC), instead the measure on the performance of the breakdown structure and the critical path method, most common used in the traditional approach (Kim et al., 2002).
Nevertheless, the implementation of Lean principles in construction requires efforts among the complete project strategy, tools and the improvement of relationships between all participants; in a continuous effort to reduce waste, time and regarding the accomplish of the costumer requirements’ maximizing the total project value (Alves et al., 2012).
The Lean Construction Institute (LCI) has developed a standard form called consensus 300 where the agreement between the owner, designer and contractor are stated in order to accomplish the Lean philosophy.
But, HOW??
The following is document agreement that is carried out but this practice.
CONSENSUS 300
The Consensus 300 is a standard form of tree-party agreement used for collaborative project delivery (CPD) system. The document is composed with a several of arrangements between the owner, the designer and the contractor; focus mainly in,
- minimizing cost and
- time during the design and construction processes.
In order to achieve this objective, this arrangement stated 25 articles comprising and applying the principles of lean philosophy and its methodology. Each article defines the specific roles of the parties, risk and the responsibilities that they should assume during the contract. (O. Salem, 2006)
The consensus agreement divided the charge and management in different groups or teams.
Collaborative Project Delivery CPD Team
The CPD team integrates all the members including the owner, designer and design consultants, contractor and trade contractors. They work towards a cooperative spirit and lean philosophy where the success of each party is tied to the others members of the CPD Team; though an open communication, transparent decision-making, proactive and non-adversarial interaction, problem-solving, sharing ideas, continuously improving and constriction processes, including the sharing of profit and risk into a collaborative relationship.
Management Group
The Management Group, included in the CPD team, is composed by the representative of the owner, the designer and the constructor; and is the ultimate project decision – making authority on the project; towards a collaborative method to achieve the highest quality and the most efficient and economical delivery of the project. The members of the owner, designer and contractor should share and provide all the project information.
The Consensus 300 is divided in several statements; as follows the most important ones are described:
A preliminary Owner’s budget shall be revised by the constructor and the designer. The design budget shall be made by the designer and the Management Group; this includes an estimate of the design and the designer’s fee.
The construction budget includes a preliminary estimate, a design contingency, a construction contingency, a general contingency (materials price, Bids, etc.) and constructor’s Fee the cost of the project components and services and it is separated from the design budget and other cost.
All project participants must to ensure quality in all instances, knowing that defects and deficiencies in the task will have an impact on cost, time, work flow and performance.
The parties can agree one of the two alternatives to the project risk distribution:
- · Safe Harbor decisions: the risk is shared between the parties
- · Traditional risk allocation: each party assumes the risk derived from his own work.
Nevertheless, if any errors, omissions or inconsistencies are discover in the design or in the construction processes, the party should inform immediately to the CPD team as part of the collaborative process.
The Designer must work in a collaborative way with the CPD team to ensure the free-flow during the design process in order to complete accurate information, cost, quality specifications, constructability and schedule.
Pull Based Design
It is the resource-loaded plan prepared by the designer and approved by the Management Group. Where is described the activities that should be accomplish in each phase of the project.
For the design documents, the designer should use pull based principles, which will help to establish the work flow in the process, adjust the scope and budget of the project.
As part of the collaborative process, a preliminary project planning evaluation by the CPD team should be done, regarding all requirements, additional studies or tests, site assessment, etc.
A project planning system shall be employed by the CPD team that includes milestone schedule, progression schedules, “make-ready” look ahead plans and weekly work plans. The most common system is the Last Planer® system. This system is divided as follows:
- Master Scheduling: this includes the identification and break-down on milestones of the total project.
- Pull planning: in this step; the necessary documentation and operational conflicts are identified
- Make Work Ready Planning: is the corroboration of the planning stage verifying if the work is ready to start and doing re-planning if necessary.
- Weekly Work Planning: to review and corroborate the schedule and work performance
- Learning: measure of the percent of plan complete, details for failure, developing and implementing lessons learned.
The pull planning governs the total master plan and schedule for the project and is created by the CPD team and approved by the Management Group; defined as follows:
“…preceding activities are not started sooner than is needed to assure the continuous performance of subsequent activities. Where the work of one Team member is dependent upon the prior performance of another Team member, the Team member whose work follows shall request of and receive from the prior performer a commitment as to when the work to be handed-off will be finished and the Team members shall agree upon criteria for the hand-off of work.” (LCI, CONSENSUSDOCS 300).
The contractor schedule specifies dates and duration of the contractors’ work included in the milestone schedule meeting the Owner’s program. The schedule has to be approved by the Management Group.
The final budget, schedule, communication protocol and building information modeling (BIM) are established between the parties after weekly reunions and in collaboration between the CPD team and the Management Group.
If a change of an activity or work is needed, a Change of order is the official document approved by the Management Group indicating the changes.
Financial Incentives are given to encourage higher performance though a benchmark program that evaluates the feature of the cost, quality, safety, schedule, planning system reliability, innovative design, construction process and teamwork.
Nowadays, when the Construction Industry is compared with other Industries is possible to identify that is behind in terms of profitability, productivity and economic growth. According to this research work the main reason is due to the current project management practice does not give proper consideration to the identification, measurement and elimination of waste.
As the main goal of this research we found that Lean Philosophy can really improve the Construction Project Performance based on our literature Review this approach mainly focuses on to achieve three basic factors; deliver the product, maximize their value and minimize the waste.
As result, using Lean Construction philosophy can lead to an increase in the safety performance by approximately 60%, in the productivity by approximately 10 %, and decrease the project duration by approximately 10%, the final cost by 20%, and re-works by approximately 50% (Janette Keiser, 2010). These reduction are possible due to the approach is based on measuring the work flow; focusing on the completion of planned work per week and measuring the Percent Plan Complete (PPC), instead of measuring the performance of the breakdown structure and the critical path method, most common used in the traditional approach. (Kim, 2002).
Nevertheless, the implementation of Lean principles in construction requires a change in the paradigm about How Construction is analysed, interpreted, and performed nowadays. Also, an important effort among the complete project strategy, tools and the improvement of relationships between all participants must be done.
References
Advisors, T. (2013). Transformance Advisors. Retrieved from Transformance Advisors: http://transformanceadvisors.com/portfolio-view/what-is-lean/
Alarcon, I., Christian, D., & Tommelein, I. D. (2011). collaborating with a permitting agency to deliver a healthcare project. Procedings of the 19th Annual Conference of the International Group for Lean Construction. Lima, Peru.
Alves, T. d. (2012). Exploring lean construction practice, research, and education. Engineering, Construction and Architectural Management, 12.
Ballard, G. (2000, sept-oct). Lean Project Delivery System. Lean Construction Institute.
Blanchard, D. (2007). Supply Chain Management Best Practices. Jhon Wiley & Sons.
Christian, D., Hurley, G., Mobley, J., & Sargent, Z. (2011). Sutter Medical Center Castro Valley: The Real
Risks and Rewards of IPD. ASHE 48th Annual Conference and Technical Exhibition.
Egan, J. (1998). Rethinking construction. U.K.: Department of Environment, Transport and the Region.
Forbes, L., & Ahmed, S. (2008). Modern construction:lean project delivery and integrated practices. CRC Press.
Ghassim, R., & Becerik, B. (2011). Transmitting to integrated project delivery potential barriers and lessons leraned. Lean Construction Journal.
Homebuilding Partners, I. (2010, June). Lean Homebuilding. Retrieved from Lean Homebuilding: http://leanhomebuilding.wordpress.com/
Howell, G. A. (1999). What is lean construction-1999. Proceedings IGLC.
Jacobs, G. F. (2010). Review of lean construction conference proceedings and relationship to the Toyota production system framework. Fort Collins, Colorado, USA.
Jacobs, G. F. (2010). Review Of Lean Construction Conference Proceedings And The Relationship To Toyota
Production System Framework. ProQuest LLC.
Janette Keiser. (2010). Introduction to Lean Construction©. white paper, 11.
Josephson, P.-E., & Saukkoriipi, L. (2007). Waste in construction projects: Call for a new approach. Chalmers University of Technology.
Khemlani, L. (2009). Sutter Medical Center Castro Valley: Case Study of an IPD Project.
Kim, D. (2002). Exploratory Study of Lean Construction: Assessment of Lean Implementation. Austin: University of Texas at Austin.
Lamb, E., Reed, D., & Khanzode, A. (2009). Transcending the BIM Hype: How to Make Sense and Dollars from Building Information Modeling.
LCI. (n.d.). CONSENSUSDOCS 300. Retrieved from www.leanconstruction.org.
LCI. (n.d.). Lean Construction Institute. Retrieved from Lean Construction Institute: http://www.leanconstruction.org/training/the-last-planner/
Lincoln H. Forbes, S. M. (2011). Modern Construction: Lean Project Delivery and integrated practices. Boca Raton: Taylor & francis Group.
Megacentro. (n.d.). Megacentro. Retrieved from Megacentro: http://megacentro.com.do/
Ningappa, G. (2011). Use of lean and building information modeling (bim) in the construction process; does bim make it leaner? .
O. Salem, J. S. (2006). Lean Construction: From Theory to Implementation. MANAGEMENT IN ENGINEERING .
Pelberg, B. E. (2009). Contracting for integrated delivery system. 48th Meeting of invited Attorneys Shinnerer Company.
Peter Simonsson, M. E. (n.d.). Increasing productivity through utilization of new construction techniques. Luleå: Luleå University of Technology (LTU).
Post, N. M. (2011). An Unprecedented 11 Partners Propel Integrated Project Delivery at Sutter's New California Hospital.
Rogers, J. (2013). What is Lean Productivity and How does it apply to Construction. Phoenix: Arizona State University.
Salmon, J., & Cardwell, R. (2008). A construction industry revolution. The voice summer.
Sive, T. (2009). Integrated Project Delivery: Reality and Promise. society of marketing professional services foundation white paper on IPD. SMPS publication.
Sudairi, A., & Abdulsalam, A. (2000). Evaluation Of Construction Processes: Traditional Practices Versus Lean Principles. Bell & Howell Information and Learning Company.
Tiwari, S., Odelson, J., Watt, A., & Khanzode, A. (2009). Model Based Estimating to InformTarget Value Design.
Umstot, D., & Cem, P. (n.d.). Umstot Project And Facilities Solutions. Construction Industry Institute.
William, A. (2006). The integrated agreement for lean project delivery. Construction lawyer volume 26.
Womack, J., & Jones, D. (1996). Lean Thinking: Banish Waste and Create Wealth in Your Corporation. New York: Simon & Schuster.
Womack, J., Jones, D., & Roos, D. (1990). The Machine That Changed the World: The Story of Lean Production. New York: Harper Collins Publishers.
Special cerdits and thanks to Bibiana Toro, Aquiles Chrsitopher, Mohemmed Albutainy, Elsadek Halawa, Sorror Zamani, Saba Mohammadi
Posted in
friendly Construction,
future,
Lean,
Lean Construction,
new philosophy,
Waste
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Written on Friday, January 17, 2014 by Jose Sanchez Marquez
The following information was the result of a Project conducted at Concordia University, Montreál, Canada called.
Use of Non-destructive Tests for Quality Assurance in Portland Cement Concretes (PCC) Pavements.
by,Matin Nabavi, Reza Mahsoudi and Jose Sanchez Marquez,submitted for the Master Course Pavement Design CIVI 6451 (Fall 2013). In addition this project was presented in the 1st Annual MSC-CTRF Transportation Conference at Concordia University.
In this post you are going to find the use of two Non-destructive test (NDT’s) Electrical Resistivity and GWT test to determine durability characteristics of new PCC pavement located in the city of Montreal, Canada.
(Note: the all project is not presented here, only some parts of it. However the final conclusion and references are fully shared).
There are several types of tests that are used to determine important characteristics and properties of Portland cement concrete (PCC) pavements before its fabrication, during its transportation and placement. However, once placement takes place, it is difficult to determine if the process of consolidation, finishing and curing were correctly developed. The appearance of cracks after some days or some years, are one of the most common warnings that something had gone wrong.Also, it is well know that deficiencies in pavement thickness reduce the life of the pavement.
Portland cement concrete (PCC) pavement is commonly used because of its capability to support compression and tension stresses, making it the first alternative in scenarios where high traffic and heavy loads are predominant.
A durable concrete is not only one that can resist a number of axle loads for a period of time, but it must also have a series of properties for the particular environment in which it is exposed during its service life (Taylor et al., 2013). Concrete durability is generally defined as ability to resist weathering action, chemical attack, abrasion, or any process of concrete deterioration.
In order to achieve durability the concrete must have good quality material, an effective construction control, and consolidation, finishing and curing must guarantee a durable concrete in order to avoid early deterioration and excessive maintenance efforts.
The Non-destructive tests (NDT) durability tests such as Water Absorption and Electrical Resistivity (Wenner probe) can determine the moisture content and permeability of the PCC pavement at an early stage.
Besides, NDT also determines the layer thickness quality assurance in PCC pavements. This method has lower time and cost compared to traditional methods like coring extraction (Maser et al., 2005). The objective of this study is to identify whether NDT tests can be useful for contractors in general or in specific areas. This is done by proving that this approach is a less time consuming and less expensive alternative for monitoring quality assurance control in the different PCC pavements.
In order to establish the pavement layer thickness, Ground Penetrating Radar (GPR) is by far the most established technology (other than coring) for measuring pavement thickness or Mechanical wave techniques, such as impact-echo (IE), that seems to work more effectively in concrete (Maser et al., 2005). The electrical resistance of a hardened concrete can be measured by the by the Wenner - four electrode probe (electrical resistance). This test can be correlated with permeability (Shahroodi et al., 2010).
The reason why the place was chosen at Westmount QC H3Z 2A6 was because during the end of summer 2013 (September) a PCC pavement was placement in this intersection.
Greene Avenue and Boulevard de Maisonneuve, Intersection 1299 Greene Ave Westmount QC H3Z 2A6
The testing date was the 11th October 2013 during the morning, for the two tests, Water Absorption and Wenner four probe were conducted and the weather air and pavements conditions were measured at that date:
Air Temperature: 14 °C
Air Humidity: 72 %
Pavement Temperature: 18.7 °C
Pavement Humidity: 82.3%
The figure bellow shows the intersection location and the street distance between the place and Concordia University.
In order to conduct the test was necessary to saturate with tap water for some minutes the concrete surface where the device is going to be place. For the field test a total time of 1 hour saturation was applied into the surface.
According to the following figure develop at Concordia University from a Master thesis research in progress called “Evaluation of Saturation Techniques for In-situ Surface Electrical Resistivity Measurements” by Dr. Michelle Nokken and Jose Sanchez Marquez. A significant decrease in the resistivity value up to 6 hours is observed but then it became stable (same value). At the end, an average difference of -9.5 % is observed between the first measurement (1 hour) and the last one measurement done at 72 hours.
A total of 24 measurements were done on each slab, 8 measurement at different slab zones (1MS, 2MS and 3MS) in order to obtain a final resistivity value. Figure bellow shows the three locations in where the device was located over the slabs.
The final Average Resistivity Value obtain for the two slabs, 13.6 and 13.4 KΩ-cm. Which means that, the resistivity value and the degree of permeability of the concrete placed at the intersection street and tested for this research work is the one expected in this kind of cement. Moreover, it also means that, for the two slabs tested the placement and curing procedure were good enough, due to the values obtained are similar to the ones obtained at laboratory conditions (ideal conditions).
The Water absorption test was conducted the same day of the Wenner Probe test, the 11th October 2013. The following weather information was measured that day;
Slab No. 01 Temperature: 18.7 °C
Slab No. 02 Temperature: 19.1 °C
Pavement Humidity: 82.3%
Once in the field, over the slab the pressure chamber containing a watertight gasket was secured tightly to the surface by two anchored clamping pliers or by means of a suction plate.
Then the chamber was filled with water and the valves closed. The top lid of the chamber was turned until a desired water pressure is achieved. The pressure selected is maintained by means of a micrometer gauge pressing a piston into the chamber (20 MN), substituting the water penetrating into the material. The travel of the piston over time was used for characterizing the permeation of the surface tested.
According to previous researches it was possible to estimate that a high pressure (permeability) and low pressure (absorption) tests could be done for duration of up to 30 minutes. Based on this results it was concluded that test duration of 20 minutes can provide sufficient number of data points in order to calculate related indices (Basheer et al., 1995). The following table shows the pressure range against test time for the two slabs.
As a result the PCC pavement tested showed a good capability to absorb water.
One of the main factors that are in the service life of new and existing pavement concretes is durability performance and durability is a function of permeability.
In this Paper Term study different types of existing permeability tests were used to evaluate the the durability of the Greene Avenue and Boulevard de Maisonneuve - Intersection, 1299 Greene Ave concret PCC pavement.
The scope of the research included the characterization of fluid transport with two different tests, Wenner Four probe test and water absorption test. Two concrete slabs were tested in this research.
The result of the Electrical Resistivity test indicates that the final resistivity value for Slab No. 01 and Slab No. 2 are 13.4 and 13.6 respectively. If we want to compare these values with 28-Day Surface Resistivity (According to table 1), it shows that the permeability of the mentioned concrete is in the range of moderate permeability class. In addition, for the water absorption according to the results obtained from the test, sorptivity index is around 2.3 for the slab and the humidity and water ratio are 83% and 0.45 respectively, so according to figure 14, Concrete is ranked as a good condition in terms of capability.
Although for this research work we contacted some companies from Montreal and from province of Ontario it was not possible to find and use a GPR or IE device in order to evaluate the thickness at the same place where the other two test were done (intersection Avenue), due to the highly cost of the equipment and also due to their complexity, is necessary to have some hours training before testing in the field. However, we really believed that the use of electrical wave as method to measure pavement thickness is going to be the more efficient, less time and man-hour consuming way to establish thickness.
Conclusions
The results presented in this term paper show the effectiveness of these two methods for determining the permeability and the capability to absorb water. Both identify that, the moderate permeability and good capability to absorb water are the result of a high cement factor, well graded and a low w/c of 0.45. Moreover, a good revibration of the concrete during the placement stage also probably helped to reduce the permeability and eventually when the intersection avenue has to be exposed to deicing salts is going to perform an excellent behave.
Regarding to Non- Destructive Test (NDT) is possible to conclude that, these tests are performed in a manner that does not affect the future usefulness of the object or material. In other words, NDT allows parts and material to be inspected and measured without damaging them. Additionally, NDT provides an excellent balance between quality control and cost-effectiveness. Generally speaking, NDT applies to industrial inspections.
Comparing traditional approaches like core extraction that is a Destructive test and requires more time and resources (money) in comparison with NDT tests.
One disadvantage that we found is that special weather conditions are required in order to do the Water Absorption and Wenner four Probe tests, the temperature should not be below 5°C, what it means that during the winter season is not recommended use these test on outside concrete expose to this weather conditions.
Al-Qadi, I.L., Lahouar, S., Jiang, K., MeGhee, K. and Mokarem, D., Validation of ground penetration radar accuracy for estimating pavement layer thicknesses. Proc. Transp. Res. Board 84th Annu. Meet., pp. 5–2341, January 9–13, Washington, DC 2005.
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Prada C., Clorennec D., Royer D. (2008) Power law decay of zero-group velocity lamb modes. Wave Motion; 45(6):723–8.
Proceq test concrete Manual. Available on internet: http://www.proceq.com/fileadmin/documents/proceq/products/Concrete/Resipod/English/resipod_SF_E_2013.06.19_low.pdf
Shahroodi, Ahmad. (2010) “Development of Test Methods for Assessment of Concrete Durability for Use in Performance-Based Specifications” M.A.Sc., Thesis submitted to University of Toronto.
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Testing of Pavements and Back calculation of Moduli, 3, 1999 (American Society for Testing and Materials: West Conshohocken, PA)
Wenzlick, J., Scullion, T. and Maser, K.R., High accuracy pavement thickness measurement using ground penetrating radar, 1999, Report No. RDT 99-003, Missouri Dept. of Transportation, February 1999.
Posted in
concrete or asphalt,
Non-destructive test,
PCC pavements,
Quality Assurance
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