Lightweight concrete with high strength
Introduction
Concrete lightweight is always considered to be low resistance. Coarse grains play an important role in changing the strength of reinforced concrete. Nearly two decades ago, a study was conducted to produce high strength concrete concrete, especially in oil projects, and they were able to There are serious limitations in this way. However, it feels like it is Beacon of high or medium resistance as a durable concrete for concrete laying in the Persian Gulf and Omani Gulf.
If it is possible to achieve a good resistance despite the reduction in specific concrete strength, the ratio of strength to specific gravity increased and the dead concrete would be reduced to a desirable condition. Concrete lightness is a requirement in a particular project. Using In spite of the efforts made before the 80’s (especially in the 1970s), the compressive strength of the lightweight concrete was not significant and limited to 50MPa. Due to the need for some oil companies in the United States For the construction of coastal and coastal reservoirs and oil shores, efforts were made in the 1980s and early 1990s. They Vanstnd using silica fume Vfvq lubricants, as well as lightweight aggregates quality and high strength to strength with more than 70 MPa and even the boundaries of 100MPa Brsnd.dr these projects, the durability, especially the issue of corrosion of rebar and reliability in ice water condensation as well as proximity to water The sea was of great importance. These studies and the implementation of these concrete workshops have opened the way for similar actions in other countries. But it is interesting to note that since the second half of the 1990s little research has been done on concrete. And it seems that there is a need for extensive research. Do not get traumatized or you do not have the necessary financial resources for researchers D. In Iran, since the late 1970s (late 1990s), attempts have been made to produce high-strength light concrete, the results of which are considered in this paper.
The philosophy of using high strength concrete concrete and applications:
Conventional concrete has a mass volume of 150.2 to 2.50 tons per cubic meter and has been able to withstand resistance of more than 60 MPa to about MPa120. If the average resistance of a high resistance concrete to MPa90 is considered to be normal, the ratio of resistance to dry mass will be 40 .
Concrete semi lightweight dry density of 55/1 to 85/1 tons per cubic meter capable Bashd.mqavmt pressure concrete semi lightweight before the 80 Mmvlabyn MPa25 to 45MPa was an average of 35Mpa the Bashd.nsbt resistance to density medium-dry in about 20 ; Therefore, the use of semisolid concrete was not justified. The total volume of dry matter had a dry volume of 1.26 to 1.245 tons per cubic meter, but its compressive strength was effortlessly exceeding 25 MPa, and the resistance to dry matter volume was less than 20 Many times, this type of concrete was not structural and was used as non-structural material. Because of the need for lightweight in some projects, They wanted to use structural reinforced concrete. Inevitably, they sought to increase the resistance, and as the conventional high-strength concrete was made, they tried to produce a semi-hard resistor of normal resistance and they had to achieve resistance to the mass of 40, The pressure was about 70 MPa to justify its use in all directions.
Although the reinforced concrete was constructed from the years of the First World War and the Second World War, the barge was used as a small, long-range warship, but later, especially after World War II, buildings and bridges in the United States and Canada with resistance push over MPa25 made Shd.sakht tanks submerged and semi-submerged, storage of natural gas, floating piers, buildings, offshore, such as oil platforms with concrete lightweight aggregates history. but since the mid-80s to 90 making this type of offshore structures with concrete semi lightweight became common .
Construction of semi-solid concrete with high strength of materials and materials:
For the manufacture of coarse semi-solid concrete with good resistance, fine sand or aggregate is used with regular gravity, which completes other cement and other mineral and chemical compounds along with water. Generally concrete concrete with a concrete resistance is specified. compressive strength of cylindrical 28 days Ybsh of 35 MPa Bashd.sbkdanh coarse usually specific gravity of mass non-condensing less than kg / m 3880 have St.sbkdanh clay beehive such as clay or Lyapvr or Fybvkh may be other names in different countries have the Including aggregates of lightweight materials in these concrete. Expanded shale including Crushed concrete is also used in some countries in Lirapore. Expanded silica (Lissa) has been widely used in lightweight reinforced concrete. Cooked fuel (litharge) and expanded plate (plate), including It’s worth mentioning that, as a general rule, the mass of a non-condensing mass of these aggregates is required to be more than 600 and up to more than about 800 kg / m 3, so that you have the right and proper strength for these concrete. Specifically, Due to its maximum capacity, Iran’s liquefied gas can reach 350-450 kg / m 3, and it is clear that resistive experiments will not be responsive.
For a lightweight concrete, the maximum size of the grit is usually more than 16 mm thick and is limited to 10 to 12 mm. The material is reduced by decreasing the maximum size, the non-condensing specific gravity,
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