CONREPNET Performance based rehabilitation of reinforced concrete structures Members workshop – London – 24 & 25 April 2006 The present and future in concrete repair Ing. G. Van der Borgh Technical Adviser FEREB

A.The present in concrete repair A. 1. What do we have : - Specialized cementious based products, - with national certification - with CE marking in the near future - A lot of contractors with good knowledge on - repair products - application technique - repair concrete technology - National Normalization guides - Neutral specification text in a lot of countries - Insurance covers with future durability options

A.2. What do we get : - A.2.1. On the product side : - Use of none certified repair products ! - Still use of resin based products outside ! - Use of cosmetic repair products on structural repairs ! - Use of none performing coatings, without any carbonation protection and even sometimes without any permeability, aggravating as such the rust action !

A.2.What do we get : - A.2.2. On the applicator side : -Minimum or even no diagnostical information available to the bidder, - obliging him to either taking a financial risk, - either to incorporate some securities, but with the risk of loosing the quote ! - Use of the lowest bidder without any preliminary control : - on his technical ability to perform an adequate and durable job ! - on the qualification of his staff and workers ! - on the used products ! - if the requested amount of money to execute the job reflect the assumed amount ! - no obligation on durability – mostly with only 1 year of responsibility ! - No site control during the job : - on qualification of workers and staff ! - to see if the specification are followed ! - to see if the given diagnostic in the specification are confirmed ! - with no segmentation and separate approval in the repair process !

A.2. What do we get : - A.2.3. On the consultant side : - He relay on the competency of the future contractor and do not see the need to provide to him a full diagnostic on the nature of the job ! - Do to this lack of information his financial evaluation will mostly be under estimated but by finding contractors, who either by ignorance, either by risk taking, will confirm this low evaluation, he initiate and encapsulate a more than probable future repair failure by choosing the cheapest contractor ! - He keeps the specs very general, due to this shortage of diagnostical information, sometimes they even contradict each other ! - He do not see the need to convince the owner to invest in a general protective coating, to prevent further carbonation !

A.2. What do we get : - A.2.3. On the consultant side also : - No formal site control exist most of the time : - To see if the qualification of the workers and staff is adequate ! - To see if the specification are followed ! - To see if the given diagnostic in the specification are confirmed ! - To segment, test and give separate approval of these segments !

A.2. What do we get : - A.2.3. On the consultant side also : - No formal procedure exist if unknown technical problems occurs, leaving this to the contractor to solve this, in the given budget ! -No formal certificate is issued at the end of the job to the owner, mentioning : - if the repair job fulfil the owners expectation and if not why ! - if eventually known and accepted shortcomings do exist and why ! - what future maintenance should be done, eventually by taking in account the known shortcomings !

A.3. What do we get as a conclusion ! - Nearly 40 % failure on the first 5 year ! - Nearly 25 % failure on the first 10 year ! How is this possible, as we have in most of these cases, the knowledge, the technology, the products and the capable contractors to do a durable job ?

The conclusion could be that : If a concrete repair fails, the contractor will always be blamed for it, but in most of the cases the consultant did initiate it : 1.By not performing a formal diagnose of the repair job ! 2.By not giving a realistic cost base to the owner ! 3.By allowing to much technological freedom to the chosen contractor due to poorly written specification ! 4.By appointing the cheapest contractor without any other consideration on competencies (technological & practical) of workers/staff and on used repair products ( Agreements & CE marking) ! 5.By not issuing any follow up paper on maintenance advice to the owner, allowing him to assume his construction will be up for eternity! 6.By not incorporating an insurance cover, which will bring additional technological knowledge into the repair job on top of the cover itself which, if a later failure will be noticed, will allow a faster repair of it, without to have to wait when the Court decide in their places !

B. What changes should be implemented for the immediate future? 1.Consultants should be convinced/obliged to do a proper survey and diagnosis of the repair job and if technological needed, should convince owners to not only repair but also protect his construction ! 2.Consultants should provide this diagnosis to the contractor, prior to his tender ! 3.Consultants will only allow registered and certified repair contractors to do the job, using CE mark repair products, fit for the job to be done ! 4.Concrete repair job should fragmented in different sections and each of them should given an approval by the consultant, before next step is been 5.Consultants should issue an document at the end of the repair job, that it is execute according the initial specs and if not, why this is done and indicate maintenance advice for the owner ! 6.Consultants will have to convince the owner to incorporate an insurance cover !

C. What changes should be implemented on the long term ? Impose that all parties involved in such a concrete repair, had to fill full their obligations, and install ways to control this. This means for me the following steps : 1. That already when a new concrete construction is handle to the owner, the contractor has to compulsory provide a document wherein he mention when the necessary first survey of this construction should be done, so that the requested performance, expressed by the owner, is maintained. Eventually, this maintenance free period could also be insured by specialized insurance companies. Also, if any shortcoming is already known and is accepted by the owner, for whatever raisons (technically, weather conditions, time shortage, etc), this should be mentioned and shorter survey and maintenance period instructed.

C. What changes should be implemented on the long term ? 2. Survey and maintenance instruction follow up, by exterior surveyor, with written report and given instruction as what would eventually needed to be done and when next survey would be needed. A copy of this report, together with the proof of the eventually necessary maintenance work which is done, should be send to the insurance company, which is involved with this construction and they could extend their cover till the next survey. Eventually, if this suggested maintenance would not de done, the insurance cover could be stopped. 3. If any main extetic or structural repair should be done, based on this initial survey, a diagnostic investigation should be done, mentioning the raison of this failure and proposing to the owner the preferred solution, again based on owner’s expectation.

C. What changes should be implemented on the long term ? 4. The tender papers should be published, with the chosen repair solution, technically described, giving all diagnostic information available, requesting quotes from only registered and certified concrete repair contractors, working with also certified personnel. Certification should be done by the National Certification body, involved in the CE marks for concrete repair mortars. Logically, these contractors would only be using CE marked concrete repair product and, depending on the specifics of the repair itself, added performance criteria could be requested. The contractor work should be divided in different steps ( ex. cleaning and taking away old concrete, application mortar, application protecting coating ) and each step should be controlled be an exterior surveyor and this should be reported, before the next step could be executed.

C. What changes should be implemented on the long term ? 5. When the repair will be finished, as with a new construction, again surveyors maintenance period should mentioned in a compulsory document, with copy to the insurance company, if any, to maintain insurance cover. Now this may seems totally irrelevant in the building industry, but if “ total quality survey” has proven his need in the industry, Why can it not be implemented in the concrete repair business ?