Molding workshop for the production of elevator shaft blocks with a capacity of 65 thousand meters per year. Technology of concrete, building structures and products

Introduction

Concrete is the main building material that is used in all areas of construction. The technical and economic advantages of concrete and reinforced concrete are: a low level of costs for the manufacture of structures in connection with the use of local raw materials, the possibility of application in prefabricated and monolithic structures of various types and purposes, mechanization and automation of the preparation of concrete and the production of structures. The concrete mixture, with proper treatment, allows to produce structures of optimal shape from the point of view of construction mechanics and architecture. Concrete is durable and fire-resistant, its density, strength and other characteristics can be varied widely and a material with given properties can be obtained. The disadvantage of concrete, like any stone material, is the low tensile strength, which is 1015 times lower than the compressive strength. This drawback is eliminated in reinforced concrete when tensile stresses are perceived by reinforcement. The proximity of thermal expansion factors and strong adhesion ensure the joint operation of concrete and steel reinforcement in reinforced concrete as a whole. Due to these advantages, concretes of various types and reinforced concrete structures from them are the basis of joint work .

Reinforced concrete is a composite construction material in which concrete (matrix) and steel reinforcement are connected in a single whole.

Reinforced concrete structures are made with conventional and pre-stressed reinforcement. The main idea of pre-stress of reinforced concrete structures is that during manufacture concrete is artificially crimped. Due to this, concrete is compressed only when compression stresses created by compression are overcome. If they exceed the tensile stress of the load, cracking in the concrete can be avoided.

Prestressed reinforced concrete structures are more effective than conventional ones. In them, the bearing capacity of reinforcement and concrete is more fully used, therefore, the mass of the product is reduced. At the same time, pre-compression prevents the formation of cracks in the stretched zone .

Reinforced concrete was invented in France in the middle of the last century and began to be used in a prefabricated version - small simple-section products :

Block house building is currently developing in four main areas, which mean a set of structural and technological solutions: Krasnodar - blocks of the "lying glass" type with linear support along the perimeter, forming the blocks in a cassette way; Vologda and Dnieper - "cap" blocks manufactured on continuous molding machines with a movable core; Minsk blocks of the type "cap," manufactured by the cassette method; Khabarovsk and Kremenchug - blocks of the "cap" type with angular support, made using vacuuming.

1.3 Selection and justification of production technology.

Production of middle, lower and upper blocks of elevator shaft is carried out by means of bench production method. The bench method of producing reinforced concrete products is characterized by the following main features: the entire production process is carried out in fixed forms or on special stands; articles remain stationary during processing, and working and process equipment moves from one mold to another; one or several technologically homogeneous articles are attached to each stand or mould. Movement of molds with articles is performed by electric bridge cranes. The advantage of the bench production method is the absence of vibration platforms and playback chambers, as well as the speed and ease of installation of equipment.

On bench lines for the production of ordinary and upper blocks of elevator shafts, the article is molded in special installations. Installations with movable core are designed for forming and heat treatment of volumetric elements of elevator shafts. The product manufacturing cycle is 6 hours. At the same time, two elements of elevator shafts can be formed.

Moulding of units is performed at EJIP unit. The EZhIP forming plant in the Dnieper OBD consists of fixed vibration shields, which are the external form of the product, and 18 replaceable movable cores. The core is a rigid steel box equipped with heating devices (TENs).

Molding machines are serviced by replaceable container cores and the necessary transport devices. The cores are prepared for molding at the posts of the conveyor line in this order: they are cleaned of concrete residues and lubricated with emulsion; on

the core is hung with a crane a spatial reinforcement frame with embedded parts fixed on it and retainers are installed; penetrators are installed on the frame and fixed with bolts. The core is fed along the rail track to the platform of the forming machine and set to the position "Concreting Start." Concrete mixture from concrete mixing compartment is fed to forming machines in self-propelled concrete laying machines along racks.

Heat treatment of the unit is carried out in a molding machine. Steam is fed into forming machine immediately after installation of core on platform and continues to be fed in process of forming and holding volume block for 2 h. After that steam is disconnected, core with product is slowly lifted up, rolled onto traverse trolley and directed into tunnel chamber. Each tunnel chamber accommodates 6 cores with articles. The total duration of heat-moisture treatment does not exceed 12 h at temperature 90... 95 ° С.

Upon completion of heat-moisture treatment, core with traverse trolley article is fed to decompression station, where article is pressed out by jacks, removed by bridge crane and transferred to one of four assembly posts. Finished volumetric blocks are transferred to one of two finishing conveyors, on which carpentry and finishing works are carried out.

1.9 Technical control at the designed enterprise

Quality control of manufactured products is carried out in accordance with GOST 1753882 "Reinforced concrete structures and products for elevator shafts of residential buildings. Specifications "

The compression strength of concrete should be determined according to GOST 10180 on a series of samples made of concrete mixture of working composition and stored under conditions established by GOST 18105.

When testing the structures of elevator shafts by nondestructive methods, the actual release strength of concrete for compression should be determined:

- ultrasonic method as per GOST 17624;

- mechanical instruments as per GOST 22690.

Dimensions, deviations from rectilinearity, flatness and equality of diagonals of structures surfaces, width of opening of process cracks, dimensions of shells, strains and edges of concrete of structures should be checked by methods established by GOST 26433.0 and GOST 26433.1.

Dimensions and position of reinforcement articles, thickness of protective layer of concrete to reinforcement shall be determined according to GOST 17625 and GOST 22904. If the necessary instruments are not available, cut-down of furrows and exposure of reinforcement of structures with subsequent sealing of furrows is allowed.

The average density of light concrete should be determined according to GOST 12730.0 and GOST 12730.1 on samples made from concrete mixture of working composition.

Methods of control and testing of welded reinforcement and embedded products should be adopted in accordance with GOST 10922 and GOST 23858.

The high quality of finished products contributes to its implementation in consumer markets, since consumers need products whose characteristics would satisfy their needs and expectations.

Quality of manufactured products shall comply with the requirements of GOST R ISO 90012001 "Quality Management System. Requirements "and GOST R ISO 90042001" Quality Management Systems. Recommendations for improving performance. " In accordance with these requirements, the organization must develop, document, implement and maintain a quality management system, constantly improve its performance in accordance with the requirements of the state standard.

The organization must define the processes required for the quality management system and their application throughout the organization, determine the sequence and interaction of these processes, determine the criteria and methods necessary to ensure efficiency both in the implementation and in the management of these processes.

Quality management system documents shall be managed in accordance with the requirements of the state standard. Records shall be maintained and maintained in working order to provide evidence of compliance with the requirements and performance of the quality management system.

The organization must plan and develop the processes needed to ensure the product lifecycle. Management should focus on improving the efficiency and effectiveness of the organization's processes rather than expecting a problem.

The organization must ensure that products that do not meet the requirements are identified and managed to prevent unintentional use or delivery. When a non-conforming product has been fixed, it must be re-verified to verify compliance. If non-conforming products are identified after delivery or use, the organization shall take actions adequate to the consequences of the non-conformance.

The organization needs to continuously monitor and record actions to improve its performance, as this can provide data for future improvements. The results of the analysis of the data from the improvement activities provide an input to the management analysis to provide information on the improvement of the organization.

To ensure the quality of the products produced at the enterprise, technological control is carried out.

Technical control is divided into:

- incoming control, including control of raw materials, semi-finished products and other materials coming to production;

- operational control - control of process parameters in the production flow;

- output control - quality control of finished products after certification

sewing of all technological operations for its manufacture .

Operational control, in turn, is divided into operational, carried out by the serving character, and technological, carried out by the TOC services and the factory laboratory.

The purpose of process control is to collect information on production modes, on the quality of the processed material and finished products.

Process control information is used to develop process improvement recommendations.

Process and quality control of finished products at the designed enterprise is presented in Table 18.