Technical specification

Production of ready-mixed concrete, as a complex activity which includes services and processes (from planning to performance), as well as transportation and placing of fresh concrete, where final result is a product which should meet designed quality, safety, and end-user requirements, in every sense. Therefore, the certificate of the fulfillment of the current legislation provisions in the Republic of Serbia which determines the conditions and requirements for design, construction and maintenance of structures and blocks of concrete and reinforced concrete (the Rulebook on technical norms for concrete and reinforced concrete ("Official Gazette SFRY", No. 11/87), hereinafter referred to as PBAB), is one of the instruments to verify production suitability and functionality of concrete plant.

Concrete plant production suitability control

Concrete of B.II category can be produced in the concrete plant in which production meet the conditions determined by Article 36 of the PBAB and by standard SRPS U.M1.050:1987 (Concrete - Concrete plant production suitability control). This standard determines method and scope of testing of functionality and production suitability of concrete plant, for production of concrete of B.II category.

In accordance with the provisions of standard SRPS U.M1.050:1987, concrete plant, in technological terms, needs to meet the following requirements with their equipment for regular work and equal quality of the produced mixture:

• conditions and equipment for adequate storage of basic raw materials;
• devices for batching concrete constituents, whose accuracy and sensitivity is checked regularly and which is calibrated according to the national regulations which determines the criteria for the metrological requirements for measuring instruments;
• a mixer(s) for concrete constituents, which by its construction and technical characteristics allows achieving required degree of homogeneity of fresh concrete mixture;
• centralized management of the production process.

Primary and control test on production suitability and functionality of concrete plant, in accordance with the provisions of standard SRPS U.M1.050:1987, includes following controls:

• control of device operation;
• control of equipment and devices condition;
• control of measuring devices;
• control of mechanism for the mixing;
• control of the homogeneity of the mixture;
• theoretical capacity of the concrete plant.

Concrete production control

Producer/manufacturer of concrete is obliged to conduct production control - by the time when concrete is handed over to contractor and concrete contractor – from the time of taking over concrete until the end of curing of placed concrete. Concrete production control is determined by the Articles 38 - 44 of PBAB and by standard SRPS U.M1.051:1987 (Concrete - Production control in the concrete plants for concrete of B.II category). This standard specifies the technical requirements for production, testing and assessment of quality of concrete which is produced in the concrete plant, until concrete mixture is delivered to transportation vehicle, and it applies to concrete of B.II category and ready-mix concrete.

In accordance with the provisions of standard SRPS U.M1.051:1987 concrete plant which meets requirements regarding functionality and production suitability for production of concrete of B.II category needs to include following under the control of concrete production:

• control of the constituents for concrete preparation when they are delivered ;
• control testing of constituents;
• control of concrete composition;
• control of fresh concrete;
• control of hardened concrete;
• evaluation of tests results of fresh concrete;
• assessment of the achieved class of concrete.

Control of equipment for laboratories in concrete plants

Laboratory concrete testing within concrete plants must meet the requirements prescribed by standard SRPS U.M1.052:1987 (Concrete - Equipment for laboratories in concrete plants). This standard specifies the laboratory equipment in the concrete factory necessary for performing testing of basic raw materials for concrete, of fresh concrete, as well as for making and storing concrete molded specimens for testing the properties of hardened concrete.