Any other Iranian standard until the development or revision of the treaty on a variety of concrete blocks.
Iranian standard in some cases not until the development of International Standards Organisation ISO standard will be valid in the first place and in the absence of the same standard as American standards ASTM, British BS and German DIN standard practice will be.Characteristics and at least passable
2-3-3-1 block wall
Simple cube-shaped concrete blocks should be completely healthy and without fault and with plaster and mortar surfaces have sufficient adhesion.
Iranian National Standard No. 70, 1357, to the hollow wall blocks of 40 × 30 × 20, 40 × 20 × 20 and 40 × 10 × 20 cm and dividing the sum of the solid components over the entire length in the same direction and parts Completing more than 50% of the block perpendicular to the load and a minimum thickness of 3 cm and block walls, the outer shell of small medium and large blocks of 4 cm is determined. These are the nominal size, actual size and length and height of the block, because of the mortar, 1 cm below their disposal. Tolerance for the width and height of block for block 3 ± 5/1 ± mm is determined. In addition to the above measures may block size and other measures agreed by the buyer and the manufacturer. The raw material specifications, manufacturing procedures and care of the blocks and dry them come in the standard that should be followed by the manufacturers.
Mix concrete used in the construction of a module block must Portland cement and sand 5/3 cup (up to half the thickness of the thinnest walls of huge blocks) and 5/2 cup of sand and 150-130 liters of water to tremble or 180-160 ml concrete for concrete Nlrzydh formed, the mixing can be done by hand or machine. If the block is done with hand instruments, the mix should gradually and in segments of 5 to 5.7 cm in the mold and separate each layer is compacted and compressed to form completely filled and then the mold by trowel is smooth and level. If the building block made with mechanical devices, the form must be filled to a certain height above the final and then shake the mixture into the molds, compacted and is smooth. The impression should be removed from the mold and immediately blocks on these pages block (Euro) [1] transferred to the appropriate location for processing, if you block production by Blvkzny mobile machines (Tkhmkn) to be performed, these blocks must be ground smooth, clean and free from pollution and soil and lined with concrete or cement are covered. Also, to avoid the sun, rain and wind, the block must be covered at locations away from the airflow produced. In the case of blocks with specific technical specifications for machine-alone machines should be given adequate attention.
When the ambient temperature is lower than 5 ° C, to block production stopped in an open area. In order to prevent the damaging effects of direct sunlight, especially in temperatures over 25 degrees Celsius, wind, washed away by rain and sprinkling wrong, the sharp decline in the early days of the cold weather and freezing temperatures, it is treated concrete blocks necessary. The time interval between the molding blocks and at least 4 to 5 hours of care operation will be. Processing may be performed to one of the following methods:
A: The treatment of water
This method is often used in hot weather is dry and does not require special equipment, except sprinklers for retaining moisture and shelter for protection from sun, wind and rain. In this method, the sprinkling depends on atmospheric conditions and will take about a week. The sprinkling method should be such that mechanical damage to the block not enter and remain wet all the time blocks.
(B) the action by warming
This method is used in work with limited dimensions and the need for equipment and facilities not great.
In this way the blocks were equipped with a heater fan and warm air passes between them. Naked on the block with care [2] In order to retain heat and moisture is covered.
A: The treatment of steam
To reduce the processing time of the blocks with steam heating method used. The processing methods mainly used in mass production blocks, steam rooms and peripherals need it. The room temperature up to 80 ºC, temperature increase and decrease blocks in this case to block the processing is done slowly, lose their water. In this case, processing time is reduced to about one day.
Regardless of what way the processing to be carried out, after the end of the periods specified above, should be protected from direct sunlight the blocks into place and the wind shifted, and for 3 weeks all they care about that, to uniformly dry, so that the remaining moisture content (2%) for the block with a specific weight 1400 kg per cubic meter (5%) for the block with a specific gravity of less than 1400 kg per cubic meter does not exceed. No wall will block the use of dry shrinkage and cracking will be used and therefore it is necessary to comply with the residual moisture content.
All blocks must be healthy, without fracture surfaces and edges and other defects that block the work is weak, so the blocks should be carefully examined when taking and the use of defective blocks should be avoided.
Pressure swing of 12 blocks of 280 kg per square centimeter should (for high levels) is less pressure swing provided that none of the blocks (75%) achieved an average of not less than the amount of swing.
2-3-3-2 block roof
At least 15 mm thick blades ceiling blocks, ceiling blocks on the beam width of the backing of at least 5.17 mm, tolerances in block 2 ± 5 ± mm in length and height will be. Cement consumption in the block for a thin blade, a little more than a block wall.
2-3-3-3 block Nmadar
Nmadar block size block wall with clear view and Batik are made. To avoid injury when breaking blocks and fading edges and surfaces Nmadar to use them in half sizes also make three height. In order to smooth the surfaces of this type to use block cement block a little bit more than usual.
2-3-3-4 block style
Block wall and ceiling light in order to reduce the dead load and reduced weight and heat exchange and consumption structures are sound. This block is made of lightweight concrete and gas concrete LWA they are the most common.
LWA block specific weight of 1,200 to 1,450 kg per cubic meter and an average of 3 samples should withstand a pressure of at least 70 kilograms per square centimeter (in the block) and at least withstand the pressure of a sample of 55 kg per square centimeter, the maximum water absorption The block is about 30 kg per cubic meter.