Product testing and verification
By ROSS MONSOURConcrete Construction
Industry calls for a shift in the way concrete specifications are handled
Commissioning and verifying delivered specifications is a key element of any construction process. It allows for a level of quality assurance that the product specified was indeed provided, and creates the basis for payment during various stages of construction.
The concrete industry has long been judged on its specifications, which normally entail reaching a required strength. This is typical for most concrete work with the exception of specialty projects that may involve architectural finishes and unique designs. The methods of testing for this verification are based on the CSA A23.1/2 -2014 Concrete Materials and Methods of Concrete Construction/Test Methods and Standard Practices for Concrete. Even as there is movement towards performance specifications, the methods of sampling and testing remain a key component of the hardened concrete testing.
Field sampling and transportation have always been an issue in the concrete business. Samples must be prepared and handled very carefully due to the cylinders being in the plastic state and must be simulated in their curing until it reaches the hardened state for testing. Any undue vibration or poor sampling procedures may result in strength testing that is not representative of what is in the structure. If this discrepancy is created and cylinder breaks are not within the prescribed specification, the long arduous task of assigning blame results in poor customer relations, distrust in the material supplied and ultimately economic hardship in the form of non-payment.
There are methodologies in place to challenge the results, but this circle of questioning the specification versus the material supplied is complicated. If you start adding up the additional costs of coring for proof, man-hours on both sides of the argument, lack arrangements by making policy statements to the effect that results obtained from only American Concrete Institute (ACI) certified technicians or CSA certified technicians are accepted by the industry. This has led to an increase in training for field certified people but has had minimal impact on the results. Pre-job meetings that outline the concrete tester and the requirements for concrete specifications have become more common, but the plans that result from these meetings need to be enforced.
A third major step was to develop an Internet portal that would be administered by the testing companies and could provide real time data transfer to all parties in an attempt to avoid future problems. To date it has had very low uptake as the testing companies have concerns with the logistics and the costs. The last attempt was to run a joint program with a major owner, the testing agencies and the concrete industry, but it never got off the ground.
Industry has come to realize that a shift in the way projects are run, with respect to concrete specifications, is needed. The process being proposed is called product verification. This simply means that the shift in responsibility for concrete quality assurance, will be taken off the back of the chute, and will become part of the concrete producer’s delivery responsibility. The producer would now hire the third-party testing agency and have control over how to conduct the tests and field sampling. This is a huge change in the concrete construction process. It is currently being reviewed at all levels.
In looking at the various aspects, the owner will still receive the test results from the same testing agency and will still define the concrete testing. Also, the owner may still conduct his own quality assurance program if there are trust issues until the process is well understood by all parties.
Benefits to the contractor will include a single source for the testing, quick turnaround on the testing, and the producer is now confirming his material through a third party. Concerns are raised about the perceived loss of control and acceptance or rejection of loads. The testing company will see a strong demand for the proper testing, increased amount of testing, better business relationships and a level playing field. Some of their concerns see this as substantive change to the business model and an increase in the liability of the firm.
Consultants providing quality assurance plans see this as a way to minimize improper testing, confirming performance for the supplier and a uniform industry response. Some of their concerns are around perceived conflict of interest, access to the data, cost increases and existing business relationships.
The concrete producer views a lot of positives with this approach. Stronger direction and control over the actual testing procedures will receive 100 per cent of the data, less issues with the testing agencies, as well as shorter response time and mix design optimization.
However, there remain concerns with the additional scheduling, frequency of testing, additional liability, and whether or not they will have industry support or bidding issues.
Several owners are very enthusiastic about this new product verification and want to implement it today. However, as with any significant shift in the industry, a well thought out plan and strategic implementation will help to guarantee long-term success.
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