CONREPNET Performance based rehabilitation of reinforced concrete structures

CONREPNET Performance based rehabilitation of reinforced concrete structures Saint Malo – 28 June 2006 Certification of the concrete repair contractor. Ing. G. Van der Borgh Technical Consultant FEREB

A. a. Preface As it is now being agreed that a lot of the failures in the concrete repair field is often due to poor workmanship of the repair contractor and …. the fastest way to improve this and to improve durability of a concrete repair job in general, is to impose a quality label on the contractor, as already is being done with the concrete repair products ( cfr CE marking )

A. b. Preface By this he will be obliged to employ qualified workmen and staff able to apply correctly the most appropriated CE marked repair products, under acceptable weather conditions, with the adequate equipment to fulfil the requested expectations of the owner !

B. History - 1. From the early 90’ till now we had : - Testing program for applicators - Overhead application of a uniform 1 cm thick layer repair mortar - Labo testing of the adhesion after aging in clima-room, requesting 80% of the recorded results of the certified repair mortar. - Initiated by the Bridge department - With the obligation to have on applicator present on the site. - Requested for work done constructions under their control. - For all other Administrations willing to follow this.

B. History 2. Shortcomings of this program : - Testing didn’t tell anything on the concrete repair knowledge of applicator - Testing program only requested by the bridge department, meaning that only the contractors involved in bridge repair were concerned, the rest of the market remain uninterested. - Price was rather high ( +/- 1000 €/applicator) -Testing certificate was owned by the applicator but paid by the contractor, meaning often that applicator move to another contractor for higher wages ! - Administratively difficult to keep data up to date who was employing these applicators

B. History 3. a. Conclusion on our past history : As more and more repair mortars did appear on the Belgian market, having an ATG (General Technical Approval), with owners and specifier being also aware of the durability aspect of a repair job, logically the emphasis was put on the remaining “weak” player, being the contractor and his team and request also from him a “quality label” ! - Therefore some 2 years ago a committee was set, together with all players concerned in the repair business, to implement a Certification system, control by the Belgian Construction Certification Association (BCCA), which will evaluate, control and follow up the contractor, his labour and staff on the requested and defined knowledge level and skills and the ability to maintain and monitor these at a high level during the time this certification will be valid

B. History 3. b. Conclusion on our past history : - Also emphasis needed to be put on the fact that the contractor, prior to his tender, needed to know all relevant diagnostics and technical information, allowing him to make a proper tender and a quality repair job, being as durable as expected by the owner. - If for what ever raisons, these diagnostics and/or technical information's can’t be provided totally or partially in the tender, the knowledge level of the contactors, his staff and labour has to be upgraded at an higher level

C. Process Certification 1. Knowing that such a certification project was going to require quite some financial investment from the contracting side in education, training and managing the system, it was imperative that these extra cost would be recovered by a mush better internal process with less external controls by controlling bodies during the entire job, but also would result in a much more honest and probably higher price settings, allowing him to do the necessary steps requested in such a certification in order to improve on the needed durability.

C. Process Certification 2. Such a Process Certification would only by accepted by the market if a neutral and recognised organisation, in our case, the Belgian Construction Certification Association ( BCCA) certifies that, after an audit against a reference scheme, this contractor has, during a certain period, the neccessary competenties and known labor force to do concrete repair work with relevant certified products, according known and accepted technologies and would filfull the owner expectation on durability. Such a set up is called ” Process certification ”

D. Belgian Process Certification As the technology on concrete repair include so much aspects, a split had to be made, based on : 1. Repair technologies Ex Carbonatation Chlorite Alkali Silica Reaction Cathodic Protection ….

D. Belgian Process Certification 2. Application technique Ex Hand applied repair mortar Self levelling repair mortar Wet spraying equipment Dry spraying equipment ……

D. Belgian Process Certification 3. The availability, partly or not at all, of all relevant diagnostic information, repair strategy and type of material to be used Ex. All information is available / strategy known / products or systems defined Information partly available / strategy known / choice of products or systems Information not available / choice of strategy, products or systems

D. Belgian Process Certification 4. Of course, not all systems for all type of repair could be set up at ones. Neither could we expect that all staff would be knowledgeable enough to tackle on their own every possible job from a to z. So we started with the most simple repair, meaning an hand applied repair mortar to repair carbonated concrete, as this reflect the waste majority of concrete repair and created the following groups :

D. Belgian Process Certification Level 1. Contractor able to fulfil instructed concrete repair jobs according to well known technologies with certified products and/or systems. Level 2. Contractors able to fulfil concrete repair jobs according instructed and certified repair technologies with his own chosen products and/or systems. Level 3 Contractor able to manage a complete concrete repair jobs, including diagnose, repair strategy, tender and manage the complete repair job. En if needed, this process certification could be easily extended to other type of repair en/or application technologies. From the 3 group, groups 1 is now ready for implementation and consist of the following elements :

D. Belgian Process Certification 5. Managing / Control and advisory committees. Before any certification could be issued, the BCCA had to set up a serial of committees in which the different parties involved were being represented. FEREB is been chosen to represent the contractors and the suppliers of repair products. Other parties are the 3 Official Belgian Regions, The National Railway, the different architect associations, the main 3 universities, etc… These committees have set up the required reference levels needed for the different peoples involved in this process. In all these committees, the BCCA will take the final decision, as they take the responsibility on the overall process certification

D. Belgian Process Certification 6. Administrative and technical audit and follow up of the contractor BCCA perform the following audit and follow up procedures, based of the EN 45004 norm : - 1. Evaluation of the following items against a required quality level : - Structure / organisation / reporting - 2 on going jobs - Knowledge and skills of management, staff and labour - Minimum knowledge levels needed per company and per site -2. Reporting procedures internally and externally on the following items : - On the performed projects, with twice a year site controls by BCCA. - On peoples competencies, referring to the performed projects. - On the used products (ATG/CE registration /batch number/quantity used, warehousing - Availability on site of handling and mixing instruction, SDS in peoples own language).

D. Belgian Process Certification 6. Administrative and technical audit and follow up of the contractor - 3. Reporting procedures internally and externally on the following items : - On control, maintenance and calibration of measurement equipment. - On acceptance of tender, evaluating if all needed administrative, technical and diagnostic information is available, prior to accept a job - On the planning scheme of each site, - On recording day by day if the required people are present, the product and equipment used, the climatic conditions on site, the testing done, the problems, if any, with the given original specification and solution given to it - On handling of complains. - On subcontractors. - On final site control, mentioning the performed tests, amount of products used, the known deviate from original specification and eventual further instruction for the owner for future maintenance of project.

D. Belgian Process Certification 6. Administrative and technical audit and follow up of the contractor PS : Specially, on request of FEREB, it was agreed that the paperwork would be kept to a minimum and a lot of items would be recorded by the contractor own people, with a yearly audit from BCCA in order to keep the cost down and controllable for mostly smaller contractors.

D. Belgian Process Certification 7. Skill and Technological knowledge requested from the candidate applicator 1. Skills Ability to mix and apply uniformly on his own, a 1 cm thick layer of repair mortar above head, on a 0. 5 by 1 meter concrete slab, made according pr. EN 1766, which prior to this, was sandblasted and kept in a climaroom (48 h by 21 °C and 60% RH). Side guidelines of 1 cm thick are acceptable. The used mortar should be a certified mortar (ATG or CE) with known characteristics. This slab will than be kept in a climaroom 21 days at 21°C and 60% RH and 7 days at room conditions and tested on the adhesion (6 core will be drilled) The candidate should achieve the following results : Average : 80 % compressive strength of the chosen class of repair mortar

D. Belgian Process Certification 7. Skill and Technological knowledge requested from the candidate applicator 2. Knowledge During the application, a serial of questions will be asked to the candidate, relevant to what he is doing at that moment and the reason why, what to do by changeable and/or adverse weather conditions prior, during or after application. Other relevant questions will be added to have an overall impression on his theoretical and practical knowledge on concrete repair. This type of “examination” was selected in order not to frighten people not familiar with the typical “schooling” approach. Both the test result and evaluation of the answers will be graded to achieve the certification.

D. Belgian Process Certification 8. Skill and Technological knowledge requested from the other candidates ( staff, management) involved in this certification Although it is been agreed that they too should have similar skill and knowledge as the applicator, their main emphasis should be one of overall knowledge of concrete repair and a thorough one of the specific repair technology for which this process certification is issued. This will be investigated by BCCA during a multiple choice session.

D. Belgian Process Certification 9. Training and education. Together with the different education organisations active in the building trade, training sessions will be organised, funded partially by governmental programs, for both the applicator and the other people, to provide them with the needed skills and knowledge to easily pass the certification requirements.

E. FEREB Belgian Federation of concrete repair contractors and manufacturers It is the aim of FEREB to convince each and every contractor and even more each and every architect and specifier, when concrete is damaged by carbonatation, to request and use this process certification, as this is one of the most important way to improve durability of such repair !