Use  foam  in  the  construction  industry.  Part  2
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Protect the surface of the concrete floor
To protect the concrete floor, which is operated in the normal mode, or is subject to wear in areas with high traffic, there are several ways to protect the surface.
   Comparable ways: their cost, appearance and ability to perform the task to protect.
   In this article, we consider three ways to finish and protect the floor. Each of them has its advantages and disadvantages.
  
   Thin fil...

Finishing compositions based on water glass. Part 3
When used as part of exhaustion moderator comes coagulation and solidification of liquid glass. However, due to the presence in the composition of Portland cement with a finishing time is an increase strength of the coating due to hydration of cement minerals. Thus from colloids formed during the coagulation liquid glass are actively assigned to the water for hydration of cement, a porous media formed tumors filled Portland cement, which leads to...

Finishing compositions based on water glass. Part 2
Studies in Berlin Institute Federal institute for Materials Research and Testing, show that the average density of 1730 kg/m3 brick large proportion of pores having a size in excess of 1 micron is more than 90% [3] and they are responsible for the increased migration of fluids through brickwork.
   Most fully meet these requirements structure obtained by coagulation and water-soluble potassium silicate forming silica with a high sp...

Modernization and repair of self-propelled machines. (3)
Hardening electrolysis BORATING hinge pins and bushings mates working equipment hydraulic excavators EO-4121 (EA-4321) gives an increase in wear resistance 4-6 times compared to the bulk quenching details.
   Taking into account the high wear resistance of brazed blades, hardened sintered alloys (see Table 1), are recommended for carbide knives dumps graders DZ-122 and RS-98, combined machine E-405 based on KAMAZ, for front dumps a t...

Specialized exhibition Architecture. Construction (END)
Mari-lime brick and gas silicate blocks
   JSC "MZSK" produces silicate brick and a half, color (white, yellow, black, red, blue, green, brown).
   For the production of silica brick used quartz sand from quarries near the plant. Limestone enters the factory with Dobryatinskogo deposit Vladimir region. Silicate brick (Table 1) is used for masonry exterior and interior walls of buildings and structures, as well as ...

Geophysical processes primers and security. Part 5
In the center of Moscow can distinguish vertical structure comprising a crashing into the Earth`s crust magma elongated cylinder (Fig. 2) [5]. In the center section marked lack of extensive vertical zone converted waves ("blind spot"), going from the depths of 70-80 km to 7.5 km. Such "blind spots" are characteristic of the earth`s crust with the introduction of monolithic dense mantle rocks such as gabbro, diabase, etc. In such a zone Tashkent e...

Finishing compositions based on water glass. Part 1
The quality of the decoration of buildings for new construction and reconstruction depend not only on their aesthetic, but also the operational parameters, as good-quality finish - a guarantee of durable service basic designs, long maintenance-free operation, the costs for maintenance and care. Traditional binders used for the production of finishing compositions, liquid glass is widely used, but it has some drawback: coatings based on it gaining...

On possible amendments to the equation Griffiths
Griffith presented a picture of destruction allowed to formulate the problem of determining conditions of the beginning of crack propagation and find its general solution.
   As seen from the above schemes, in the process of crack propagation material directly adjacent to it "coasts" unloaded relaxes. This means that the stress and strain it decreases, and the elastic energy stored earlier in this area of ​​the body is re...

Construction skyscrapers - the requirements of modernity. Part 4
The program is a high-rise building in Moscow
   The project is now a high-rise building in Moscow is implemented in two main areas: the construction of business center "Moscow City" and implementation of the program of the Government of Moscow "New Ring of Russia."
   1. Moscow international business center "Moscow - City"
   The project includes the construction of buildings on the territory of abou...

Degree project - beginning of the road. (3)
Given the great diversity of subject matter and content of diplomas in various specialties, the jury is faced with great difficulties in determining the winners - "Who better violinist or a dancer?". Nevertheless, often based on emotional perception and can estimate the relevance and novelty, and the author`s contribution to the thesis project or job. Absolute winners in recent years have been graduates of Rostov CSO GASU St. Petersburg, Nizhny N...

 

 
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 Use  foam  in  the  construction  industry.  Part  2

Compressive strength of concrete used in the structural elements, usually in the range of 30-40 MPa, and the above results clearly show the possibility of reducing its own weight structures and 50% without any reduction in the compressive strength.
   Cost is a major issue in the development of any infrastructure, therefore reducing the cost of construction materials used in large volumes and waste by-products.
   Previous studies indicate that in the aerated concrete in large quantities can be used fly ash. Despite the fact that high content of ash leads to reduction of strength at an early age, long-term durability can be improved by substituting up to 75% ash cement. [3] Was established optimal dosage ash, providing the highest compressive strength, and this optimum increases with the age of the material. Ash content, while ensuring maximum strength after one year is about 60% of the content of cementitious materials, but using foam concrete monolithic structural elements should be increased speed curing.
   Steam curing can be used to improve the speed of curing [4]. Impact on the initial temperature of the concrete has an adverse effect on the strength of concrete. This decrease in strength due to the formation of microcracks caused by temperature gradient [6]. The increase of air pores and voids in the foam concrete limits the harmful effects of thermal gradient.
   Curing temperature has a significant influence on the development of strength foam, and depending on the production process and the timing required for the shipment of the material curing speed can be adjusted. At 70 C the maximum strength is achieved within three days, that is 50% higher than the strength as measured in 28-day age hardening at a temperature of 22 C. Even after seven days strength foam, tverdevshego at 40 C, above the 28-day strength of the foam at 22 C. Lack of curing is accelerated to reduce the ultimate strength, and the results of the tests show that the foam, tverdevshy at 40 C, has high rupture strength.
  
   Density foam
   Density foam is manifested in long and short-term deformation of the material. Modulus of elasticity (Young`s modulus) is a function of foam density. Lower density foam concrete deformed significantly more than would be expected in the case of ordinary concrete, and design engineers must take into account the material properties of low density in their calculations.
   Air shrinkage of foam concrete is significantly higher than that of conventional concrete. Filler content in conventional concrete reaches 75% by volume, restrains the shrinkage deformation, while in aerated concrete, where the aggregate is partially replaced by air pores, shrinks, about 4 times the values ​​for conventional concrete. Decrease in density leads to a slight increase in shrinkage.
  
   To be continued.
  

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