Proceedings of 10-th International Conference on Mechanics and Technology of Composite Materials – September 15-17th, 2003 - Sofia, Bulgaria

An essential element of the new approach, laid down in the EC construction directive, is the unification of both the technical requirements to the construction products and the implementation of standardized criteria for assessing the capacities of manufacturers to supply the market with the product especially requested by the customers.
As the standards of the ISO 9000 series evolved from 1994 to 2000. the manufacturers began to apply standard practices in their activity related to quality management. This evolution aimed at guaranteeing the consumers' interests and logically developed towards standardizing the requirements to the production control on construction products. In this sense, the requirements to the production control on construction products are not only a step towards specifying the requirements of Art. 7.5.1 of the ISO 9000 series but also a real step forward to the gradual transition to the implementation of systems for total quality management,
We should emphasize an essential point in the requirements to the production control systems (PCS), viz. that the requirements to PCS do not involve only production requirements and mechanistic addition of some other compulsory procedures according to ISO. This becomes obvious when setting up PCS in enterprises that have not introduced quality management systems (QMS) according to ISO.

І. Basic assumptions

The analysis of the requirements to the products and the relevant PCS, made on the basis of EN for concrete and mortars (BS EN 206-1:2002 Concrete Part 1: Specification, properties, production and conformity and BS EN 998-1:2003 - Technical requirements to masonry mortar. Part 1: Plastering and rendering mortar and BS EN 998-2-2003 - Technical requirements to masonry mortar. Part 2: masonry mortar) enables us to identify a key characteristic of this type of standards, namely, that in terms of their nature they can be interpreted both as technical and ay (if not to a greater extent) management requirements.
This conclusion is of a particular methodological significance since it permits reformulation of the problem and transforming it into a management one thus necessitating an adequate management solution.
"Thus posed, the problem can be reduced to a normal management problem for which the key conditions for verifiability are prescribed in the respective standard/product group.
In this respect, a logical question follows as to what extent in the respective standards (in this particular case BS EN 206-1:2002) She prescribed conditions are necessary and sufficient having in mind lhal the standard prescribes both technical-technological and certain specific requirements to the management system.
Without pretending to have provided an exhaustive answer to the question, we believe that its interpretation leads to the conclusion that the requirements laid down in the standards prescribe the necessary but not sufficient conditions for developing the particular management model.
The adoption of a management approach to setting up a PCS poses two main problems that have to be solved by the PCS:

- A   group  of problems  relating to the practical   implementation  of the developed management model;

- Current maintenance of the model and its stability under extreme conditions;

Requirements  resulting from the "easy implementation" factor

This type of problems refers directly to accounting for the educational and qualification level of the manufacturer's personnel, their culture and management habits.
In practice this means that during the initial scanning the manufacturer should make a detailed survey of this group of problems.
The preliminary analysis is required to determine what type of formulation and formalization of the model can be comprehensible and acceptable for the manufacturer at minimum resource costs -time and money for initial training of the personnel to adopt the model adequately.

Requirements related to the PCS stability

One basic characteristic of concrete production is the its distinct seasonal character with clearly recorded peaks of maximum and minimum loads as a general rule. This specificity should be taken into account in setting up a PCS since from a management point of view the model is an implicitly necessary condition.
In this case we will interpret the PCS stability as the capacity of the system to function efficiently under conditions of abrupt changes in the environment.

From another viewpoint, the emphasis on the stability of the PCS model seems to be a key issue because of national specificities such as insufficient (as a rule) mastery of the quality of aggregates supplied and the relatively high failure rate of the equipment used.
The analysis of these requirements has a direct effect on the characteristics that the PCS itself should have.
For example, the requirements for PCS stability presupposes a certain "excess" of control that should guarantee the effective operation of the system under stress and peak fluctuations. From this point of view, the fulfillment only of the requirements to the PCS, laid down in the standard, is at least insufficient
The second group of problems is related to the type of management model that would permit the optimal solution to the expected range of problems such as:

•  Ensuring the required technical and technological production indices;

•  Ensuring easy and natural maintenance of PCS under real operating conditions;

•  A purely management support of the activities and functions induced by the complex of
processes.

From the viewpoint of the organization envisaged in the management model and taking into account the requirements mentioned above, initially it seems that a solution of the linear or linear-functional type of management structure is required. An additional asset of this type of solution is its simplicity and easy involvement in the existing and prevailing (under Bulgarian conditions) management practice, and the system itself would look quite orderly.
However, these obvious advantages lead to voluminous documentation, on the one hand, and again lead to the raising to the maximum the operative responsibility for the complex of implemented processes.
The other solution model is the matrix one. It delegates the responsibility to the concrete operative executors, permits maximum utilization of specialization and, last but not least, relatively easy involvement of the whole complex of processes that ensure the continuous production conformity.
In fact, the matrix solution adopted came as a direct consequence of the analysis we made of the Standard requirements. The requirements themselves are multidirectional and concern the technology and conformity evaluation, on the one hand, and the requirements to the maintenance of machines and equipment, measuring and testing devices, requirements to the personnel, etc., on the other. At the same time, the Conformity Regulation itself presupposes personalization of the responsibility.
Despite the complexity of the PCS development for this type of process management, its main advantage is its compactness and easy operational maintenance. This type of solution also permits quick implementation of the system in practice at minimum costs. A basic factor for that is the relatively low critical attitude of the system to additional qualification. This is due to the fact that in the stage of its development, the specific tasks proceeding from the PCS are addressed to their natural executors. In this sense, when implementing the system, it is necessary to make minimum preliminary efforts for raising the qualification level of the personnel. We have to assume that it is normal for any management system of the matrix type to concentrate the main load on the system coordinator, in this particular case, the quality manager.
A very substantial asset of the matrix solution is its inherent complexity and the provision of the necessary excess of control by minimum records. This is achieved at the expense of the complex character of the control. For example, two or more processes of different nature are monitored at one control point. On the other hand, besides control, mutual self-control is carried out. This minimized the risk of recurrent errors in the system. In this particular case it may be more precise to talk about multiplicity of control rather than "excess" of control.

ІІ. Implementation

The PCS developed in compliance with the principles laid out above, requires about three months to be implemented in real conditions. This term includes the time for the PSC development, the time for introducing into production and the time needed for testing the product manufactured under an operating PCS in order to make an initial assessment of its conformity.

The evaluation of the one-year experience in PSC implementation enables us to emphasize the following characteristic points:

1. About 1 to 2 weeks needed by the personnel directly responsible for implementation to overcome the initial stress caused by the bulk of documentation;
2. Overcoming certain confusion in the personnel related to the operative finalization of the documents reflecting the production and control process. This discomfort results, on the one hand, from the need for continuous recording of the processes for which they are responsibility, and on the other, the need for documented undertaking of personal responsibility for the tasks executed. In this connection, the manufacturers who do not have the necessary equipment for computer batching of composite materials are facing serious problems since the records have to be kept manually.
3. Creating a systematic habit for a continuous control on the input composite materials.
4. Need for a formal specialized training of the customers in view of the fact that the concrete production is the first to introduce a PCS. Certain problems can be identified at the first stage when the clients make out requests in conformity with the requirements of the standard and their signing. Of similar character are the difficulties in drawing up the dispatch notes by the user, especially when the concrete mix is treated on die site against the regulations.
5. A certain problem presents the readjustment of the product control frequency, the strength on the 28lh day, towards enhancing the control on the input composite materials and the operative control on the product conformity. A specific factor in this respect is the habit of many customers to continually require strength reports on the 28'h day since basically they are used to transfer the input control on the product to the manufacturer. This creates certain difficulties for the manufacturer because sampling has to be performed much more frequently than required by BS EN 206-1.

As a common problem encountered in all companies where we have introduced PCS is switching over to testing the product in conformity with the European standards. Practically, the problem is related to the need for re-equipment of the labs, i.e. the need for investing about EUR 10,000-15,000 for lab equipment.

On the basis of the accumulated experience in introducing PCS we have found out that the basic condition for successful implementation of PCS for concrete and mortars is the internal conviction of the Top Management that this step should be taken despite the initial problems. In some companies where this conviction is missing, or at least is not demonstrated explicitly before the personnel, the implementation rates are as a rule very slow and the implementation itself takes place in a very difficult way.

ІІІ. Results

From the observations made on companies that have implemented PCS we can ascertain:

1. Stabilization of the end product indices in time;
2. An increase in the general technological culture in the enterprise without involving
   additional resources;
3. A general enhancement of the quality requirements both within the company and with respect to its suppliers.

A serious advantage of the PCS implementation is the setting up of a detailed technological database which, based on statistical evaluation, permits optimization of the recipes.

Conclusions:

1. There are no serious obstacles to the implementation in Bulgaria of the European standards requiring the presence of production control systems;
2. There   are   no   special   preliminary   requirements   (exceeding   the   normal   production requirements) to the implementation of PCS for concrete;
3. The technological equipment of the manufacturers is a sensitive but not a limiting factor in the PCS implementation; 
4. In terms of cost effectiveness, when implementing PCS the economic efficiency is directly dependent on the relation: production/productivity/ technological equipment available;
5. As a whole, very fast mobilization of the entire technical and technological know-how available in the company can be observed. At the same time, even in companies where quality management systems according to ISO 9001 have not been introduced, a serious process of documenting and storing the accumulated know-how in a systematic way has began. A gradual optimization  of the  structure  of production costs has occurred as  a   logical consequence;
6. The achievement of the essential requirements to concrete does not present a special problem for the manufacturers. 

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