Concrete and ordinary glass? Do-it-yourself glass concrete manufacturing technologies Pros and cons

The topic of waste disposal is very relevant today, and I want to pay attention to glass containers. Its share in urban dumps, as well as in spontaneous dumps in forests, is very significant. This is due to the elementary lack of awareness of the population about the benefits of adding broken glass to concrete solutions. It has been scientifically proven that the addition of broken glass significantly increases the strength of concrete.

So, it took us at least a thousand bottles to concrete the roof of the garage. Picked them up right on the street. If summer residents knew about the benefits of broken glass, then the percentage of bottles in trash cans would be significantly reduced.

The addition of broken glass creates a reliable waterproofing and prolongs the life of the concrete. But you need to take precautions when breaking bottles. You need to wear goggles and hit in a container, in a bucket for example. It is most convenient to grind glass between two bricks.

Please pay attention to this issue. You just need to inform the population, talk to them, explain the inadmissibility of throwing away, for example, batteries with food waste, and so on. It's all about good organization.

Tatiana Lanskaya

Northern summer resident:I have never heard of a roof being concreted in this way, but everything related to the foundation, steps, home-made garden tiles, etc. quite fair. So far, here is some prefabricated everyday experience:

1. "From personal experience, I know that any glass containers and even broken glass can be used in the manufacture of floors on the ground. For this, a special hole is dug with a depth of no more than 20 centimeters. Then it is covered with any glass. In this case, all broken glass acts as a filler ". The floor itself is laid on top of the glass. Do not forget that in this case, glass containers can become the most reliable protection against various living creatures, for example, from moles. Empty bottles can replace even the highest quality insulation. Previously, only empty bottles were used in the construction of country houses. Their laid in continuous layers under the floor. They were also used when laying out the concrete blind area. "

2. "The only acceptable and safe way to use broken glass in construction, I would call its use in the drainage layer under the foundations. That is, you can pour pre-crushed glass, along with sand and gravel, into a pillow for pouring the foundation. Why is it undesirable to use it as a filler in concrete solutions (instead of crushed stone)? Because glass, unlike crushed stone, is smooth, therefore, its adhesion to the cement-sand mixture will be insufficient. Thus, the resulting concrete will be weaker than that made on the basis of pure crushed stone. "

3. "It is possible to dispose of cullet, using for laying the foundation, using binders, in the form of a solution with the addition of 1 part of M400 cement, 2 portions of sand and one part of cullet. The bottles must be carefully broken so that their fragments, such as the neck, do not remain intact , which may not be filled with mortar, so reliable foundation strength will not be achieved. And from whole bottles, foaming each neck, you can build a fence. So, you should not throw away such an economical and environmentally friendly building material. "

4. “We also found a lot of glass containers in our dacha. When they put up a bathhouse, a neighbor advised to cover the underground under the bathhouse with empty glass bottles, having previously dug a hole in the form of a cone. Here, along the slopes of this cone, put the bottles with their necks down, simply drowning them in the ground. What gives such a device: firstly, water flows down and does not accumulate under the floor, as a result, the wooden floor is less prone to rotting, and secondly, the glass heats up when we heat the bathhouse and retains heat for a long time - the floors in the bathhouse become warmer" .

5. "Indeed, glass containers are often used in construction if there is one. If you have the desire and enough time and, most importantly, patience, then it can be mixed with screenings and poured into concrete. Most importantly, glass containers must first be crushed very well. The unground version for use in concrete is not a very good option.For grinding, as an option, you can use a concrete mixer necessarily filled with water so that glass fragments do not fly out of it when turning."

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However, the expansion of the extraction of the main types of concrete aggregates cannot always be realized. Deposits of non-metallic materials such as building stone, sand and gravel mixtures and building sands cannot always be used, since they are built up, located in floodplain terraces of rivers or in other protected areas. At the same time, household and industrial cullet, which is not currently marketed, but has high strength characteristics and availability, is practically not used as a concrete filler. In our country, about 35-40 million tons of municipal solid waste is generated annually, while only 3-4% of MSW is recycled. The amount of cullet for different territories is 6-17 wt. %. The annual volume of cullet that ends up in solid domestic waste landfills is 2-6 million tons. Compared to the annual need for aggregates, this value is small, but it is necessary to take into account the environmental effect not only from the disposal of the MSW component, but also the possibility of reducing the extraction of natural resources when replacing on raw materials of anthropogenic origin. In addition, the use of waste is 2-3 times cheaper than natural raw materials, fuel consumption when using certain types of waste is reduced by 10-40%, and specific capital investments by 30-50%.

However, the problem of the interaction of soda-lime silicate glass with cement stone creates serious problems when using cullet as an effective filler in cement composite materials. The same can be said about many glass-containing materials - mineral and glass fibrous materials (wool), fiberglass, foam glass, which could be used as effective aggregates in cement compositions.

As a result of the alkali-silicate reaction, a gel is formed, which swells in the presence of moisture, leading to the formation of cracks and the destruction of concrete. This reaction can also occur in ordinary concrete if the naturally occurring filler contains reactive (usually amorphous) silica. On the one hand, the glass filler contributes to the alkali-silicate reaction in concrete due to the fact that the glass contains Na + on the surface, which can create a certain concentration of NaOH in the cement composition even in the absence of alkali in the original cement, and on the other hand, it is glass that contains compounds on the surface silicon oxide in amorphous form. Known studies of soda-lime glass as a cement paste filler. In this case, cullet of various composition and dispersion was added to the cement composition, and the expansion and strength of the resulting concrete were mainly investigated. So research was carried out at Columbia University (USA) by Professor S. Meyer. It was found that the addition of glass to the composition in most cases leads to the process of alkali-silicate interaction and a decrease in strength. Also studies of the effect of temperature and glass composition on the process were carried out. Highly dispersed glass powders have been found to result in no sample expansion. The authors make an assumption about the high rate of the alkali-silicate reaction in this case, which leads to the completion of the process in 24-28 hours, as a result of which the expansion and destruction of the samples cannot be recorded in the future. It can be assumed that as possible ways to suppress the process of alkali-silicate interaction in glass-cement compositions, the authors propose the use of glass of a certain granulometric composition, the addition of fine glass, and the modification of the composition by adding lithium or zirconium compounds.

Rice. one. The dependence of the strength of concrete compositions on the size of the glass filler in different periods of time with and without additional alkali in the composition: 1 - at the age of 13 weeks without alkali; 2 - at the age of 1 week without alkali; 3 - at the age of 13 weeks

In this paper, various options for suppressing the alkali-silicate interaction were considered when using glass cullet and its processing product, foam glass, as fillers.

The experiments were carried out in accordance with ASTM C 1293-01 at elevated temperature. To do this, standard samples of concrete 250 mm long were kept at a temperature of 60°C for three months. Samples were periodically removed from the oven to control expansion. After the sample was cooled to room temperature, its length was measured using an optical dilatometer. The strength control of the samples was carried out on an IP 6010-100-1 compression test machine. For the manufacture of samples, standard cement M400 produced by the Pashiysky cement plant was used. Cullet was obtained by crushing in a hammer mill followed by grinding in a vibrocentrifugal mill VCM_5000. Used granulated foam glass produced by CJSC "Penosital" (Perm).

To assess the intensity and depth of the alkali-silicate reaction, a number of experiments were carried out on the interaction of cement material with glass of various fractions, both in the absence of additional free alkali in cement and in its presence. The main parameter characterizing the course of the reaction is the expansion of samples of concrete composites. An indirect confirmation and consequence of this reaction was a decrease in the strength characteristics of the obtained concretes. As reference samples, in which the reaction should not proceed, concretes with a crystalline filler - quartz sand were taken.

It was revealed that a significant expansion of the samples, characteristic of the alkali-silicate interaction, is observed only in concretes with large maximum of the studied fractions, more than 1.25 mm, and the effect is enhanced with the additional introduction of alkali into the composition of concretes. The dependence of compressive strength on the holding time of concretes made it possible to reveal an abnormally high strength value for samples of alkali-free concretes when using fillers of both the minimum and maximum investigated fractions. Moreover, the strength of the resulting concretes significantly exceeds the strength of concretes without glass filler. This feature suggests a significant effect of the size of the filler fraction on the strength of the resulting concrete. The corresponding dependences of concrete strength on the filler fraction in the initial and final periods of cement stone formation are shown in Fig. one.

On all curves, a pronounced minimum can be traced, corresponding to the filler fraction 0.1-0.3 mm. The nature of the dependences of strength on the dispersion of the filler remains unchanged - with a steep increase in the area of ​​decreasing the size of the filler and a smooth increase in the area of ​​increasing the size of the filler particles when using alkali-free compositions and a slight increase and stabilization of strength in the area of ​​increasing the size of the filler particles when using alkaline compositions. Over time, the nature of the curves does not change, but they shift upward - to higher strength characteristics as the cement stone hardens.

Therefore, the use of coarse cullet - preferably 1.2 mm or more - is possible as a filler in concrete, and the strength of these composites exceeds the strength of ordinary concrete on sand aggregate. However, when using such aggregates, there are at least two problems associated with the possibility of alkali-silicate interaction. Firstly, the presence of free alkali in cement or other concrete components inevitably leads to the occurrence of alkali-silicate interaction and a decrease in the strength characteristics of concrete. Secondly, in the process of large-tonnage production, it is difficult to prevent spontaneous crushing and abrasion of a large fraction, which will also inevitably lead to a decrease in the quality of the resulting concrete. When the filler particle size is less than 50 microns, an abnormal increase in strength occurs, which significantly exceeds the strength of compositions on a standard quartz sand filler. Such an increase in strength can be explained by the ability of dispersed glass to enter into the processes of formation of new phases during the formation of cement stone due to the high specific surface area of ​​glass powders. This feature of highly dispersed glass can be used both to suppress the process of alkali-silicate interaction in those concrete compositions when the reaction takes place, and to create binders based on dispersed glass.

The problem of large fractions of cullet with a high content of alkali, as a filler in concrete, can be partially solved with additional suppression of the reaction of alkali-silicate interaction. For this, two easily implemented technological ways are outlined.

Rice. 2. Concrete with aggregate of foam glass gravel at various degrees of filling: a) ratio (mass.) foam glass / (cement + sand) 0.265; b) ratio (wt.) gravel/cement 1.6

Concrete has been widely used in construction for many years due to its resistance to deformation and durability, but the material also has some disadvantages, the most important of which is low tensile strength. Most often, this problem is solved by metal reinforcement, but in our time more progressive solutions have appeared. You can make glass concrete with your own hands, while the material properties will be at the highest level while reducing the weight of the structure.

In the photo - the use of fiberglass allows you to give even thin concrete elements unsurpassed strength

Main types of materials

We note right away that the concept of glass concrete means a whole range of variations, we will not consider all of them, we will only get acquainted with those that are most often used and with which you can work independently. Each type has its own characteristics, which determine certain properties of the material.

composite concrete

The second name of this option is glass-reinforced concrete. It is very similar to conventional reinforced concrete options, but glass concrete technology involves the use of fiberglass rods instead of metal reinforcement.

To explain all the advantages of composite reinforcement, let's compare it with conventional metal reinforcement:

Such reinforcement is superior to metal in all respects, which is why it is very widely used in modern construction.

Another important advantage is that composite rods are 2.5 times stronger in tensile strength, which makes it possible to use smaller diameter products without losing the strength characteristics of the structure.

Work on creating a reinforcing belt of this type is much easier and faster due to a number of reasons:

• Light weight material.
• Ease of connection - with the help of plastic clamps that securely fix each node.
• In winter, metal is very cold, while fiberglass does not freeze through.

Laying a composite armored belt is much easier than using metal

Important!
It is worth remembering that the strength properties of fiberglass are much higher, so smaller diameter reinforcement can be used without loss of strength.

glass filled concrete

Such glass concrete has a number of differences, the main of which is the use of fiberglass as a filler, which determines the high performance properties of the material.

Glass fiber resistant to alkalis and other adverse effects

The main advantages of this option are the following:

• Versatility: both panels and blocks or light and strong cladding sheets can be produced in this way. The scope of application is very wide.
• Ease: the composition includes fine-grained concrete mixed with sand in a ratio of 50/50 and chopped glass fiber.
• Strength fiber-reinforced concrete: in compression it is twice as stable as simple concrete, in tension and bending it is 4 times stronger, and the impact resistance is 15 times higher.
• With the help of various additives: plasticizers, dyes, water repellents - the properties of concrete can change significantly.

But it is worth noting that the manufacture of such material is a rather complicated process, and high quality and reliability can only be achieved in the factory.

Fiber concrete sheets have a peculiar structure and can even be used as a final finish.

Concrete with the addition of liquid glass

This option cannot be called glass concrete in its pure form, however, it is worth considering it, since liquid glass is used in production. This silicate-based component gives the material high moisture resistance properties and increases resistance to high temperatures.

In addition, liquid glass has pronounced antiseptic properties, due to which it is often added during construction in swampy areas, where dampness has a particularly strong effect on structures.

Liquid glass gives concrete the highest properties of resistance to both moisture and high temperatures.

Instructions for the preparation of concrete is as follows:

• First, concrete of the desired grade is prepared, while you should not make it too liquid.
• Next, liquid glass is diluted with water in the proportion indicated in the instructions on the package.
• The finished solution is added to concrete in a ratio of 1:10, after which it is necessary to mix the composition thoroughly before use.

Important!
Water that is added to liquid glass is not taken into account when preparing concrete, as it goes to maintain a chemical reaction that makes the surface resistant to moisture.

It is important to mix the solution thoroughly, then the entire surface will be protected from moisture.

Sometimes a simpler method is used: impregnation of the surface with a solution of liquid glass. But in order to achieve the best protection, it is better to apply another layer of solution with liquid glass for concrete from above, especially since it hardens quickly enough, so the time for the work will not increase.

Everyone knows that cutting reinforced concrete with diamond wheels, as well as diamond drilling holes in concrete, are fraught with many difficulties. But the use of fiberglass elements also simplifies these difficult jobs: the material lends itself much better, and crowns and discs wear out less quickly.

Fiberglass concrete is much easier to drill

To understand the issue even better, watch the video in this article, which clearly shows some of the nuances under consideration. In general, it is safe to say that the future belongs to fiberglass elements, and glass concrete will be used more and more every year.

Concrete is the most popular building material. It has many advantages, but there are also disadvantages. Its most important disadvantage is its low tensile strength. You can remove this feature with fiberglass. Its addition to the mortar makes the concrete structure stronger. Glass concrete is easy to make with your own hands, it is lighter, has very high properties.

Definition

Glass concrete differs from the usual high performance properties and advantages. Advantages of glass concrete:

• versatility of application - blocks, panels, sheets for cladding are made of glass concrete;
• lighter, main components: fine-grained cement, sand - equal proportions, fiberglass;
• high-strength - the material is resistant to stretching, compression, bending, impact resistance is fifteen times higher than that of a standard solution;
• A variety of additives positively affects the properties of the material.

Factory-made glass concrete is of a higher quality than hand-made.

Classification and characteristics

Glass concrete is classified according to its composition:

• composite concrete;
• composition with ;
• with glass fiber;
• with optical fiber;
• with broken glass;
• with glass acting as a binder.

Glass-reinforced concrete is similar in its characteristics to reinforced concrete. Instead of metal rods, composite concrete is reinforced with fiberglass. The main advantages of composite reinforcement:

• resistance to moisture for a long time;
• low weight fiberglass rods;
• affordable cost;
• fiberglass material can be rolled up in coils of 300 m long, this ensures easy transportation;
• provides high thermal insulation.

The strength of the composite bar is 2.5 times greater than that of steel at break. Due to this feature, fiberglass rod is needed thinner. and the creation of a reinforcing belt from glass fiber is easier and faster due to its following features:

• a light weight;
• secure fixation with plastic clamps;
• does not freeze in winter, facilitating construction work at low temperatures.

Composite concrete is less susceptible to aggressive environments. Unlike glass-composite reinforcement, reinforced concrete, subject to corrosion, can cause a break in the structure from the inside, completely collapse.

The thickness of the composite concrete can be less without affecting the quality of the structure. The weight of the structure becomes less, the strength remains at a high level. Glass concrete reinforcement does not require additional protection, like conventional metal reinforcement. The foundation can also be made not reinforced, thanks to light reinforcement.

Concrete with the addition of liquid glass

Liquid glass is a silicate-based component that makes the material durable, resistant to water and high temperatures. For construction in marshy places, liquid glass is used as an antiseptic. Used for hydraulic structures, foundations, when laying stoves, fireplaces, boilers - for bonding.

Methods of using liquid glass (sodium silicate):

• Fiberglass is diluted with the required proportion of water to the desired consistency. 0.5 l of liquid glass is introduced into 5 l of mixed concrete solution. Water for sodium silicate dilution is not taken into account. The concrete structure acquires a disadvantage: it becomes more fragile, cracks.
• The concrete surface is primed with sodium silicate, then covered with a layer of a mixture of concrete with liquid glass. This is a good way to protect the structure from moisture. The main condition is to perform a primer, plaster within a day after pouring the solution for a strong adhesion of the layers.

Concrete mix with sodium silicate hardens quickly - within five minutes. For high-quality work, glass is diluted with water, made in small portions.

The composition of glass fiber reinforced concrete includes alkali-resistant glass fiber. It is a versatile building material. Without it, the production of monolithic blocks, sheet material is not complete. The composition may include additives: acrylic polymers, quick-hardening cement, dyes. Advantages of fiberglass concrete:

• resistance to water;
• strength;
• ease;
• high decorative qualities.

The composition of the material includes: fine-grained initial concrete mortar (filler sand - no more than 50%), fiberglass. Differs in high strength characteristics in bending, stretching, compression, impact.

Chemical resistance, resistance to frost is also at a high level. Filling the solution with fiberglass is a laborious process that requires uniform distribution. Add it to the dry batch. The mixture becomes stiff, less plastic. In a large layer, vibrocompaction is required. Sheet material is produced by spraying.

Fiberglass concrete

The composition of glass-optical concrete (Litracon) includes: concrete matrix, glass long fiber, specially oriented (including optical). Litracon blocks have glass fittings. The material is transparent and has glass fittings. At home, it is used as a decorative building material. In an industrial building, its thickness can reach 10 m. The cost of glass-optical concrete is high, experts are looking for an opportunity to make the material cheaper.

The issue of developing compositions and technologies for obtaining building materials based on industrial and household waste for many years, and especially recently, excites the minds of researchers working in the field of building materials. Binders, concretes and products using various slags, sludges, ashes, wood chips, as well as construction waste generated during the demolition and reconstruction of buildings and structures have already found application. But the researchers don't stop there. After all, the relevance of the development of compositions and materials with their use is dictated not only by environmental, but also by economic factors.
In recent years, along with the already known and traditional in a certain sense, waste, the disposal of unsorted cullet of artificial (technogenic) glass, or simply cullet, has attracted particular interest. The fact is that the marriage or broken glass formed during production is in most cases reused by the same factories. Such glass has a stable (within the framework of this technology) chemical composition and is used in the process of batch melting. Unsorted cullet of various types of glass (window, container, optical, etc.) has a fairly wide range of chemical composition. Plus, foreign impurities are possible, the ingress of which into the raw mixture is not permissible if it is desirable to obtain glass with a certain composition or quality. Therefore, unsorted cullet, which is formed in huge quantities in dumps and landfills, still does not find proper use.
It should be noted that from an environmental point of view, glass is considered the most difficult waste to dispose of. It is not subject to destruction under the influence of water, atmosphere, solar radiation, frost. In addition, glass is a corrosion-resistant material that does not collapse under the influence of overwhelming amounts of strong and weak organic, mineral and bioacids, salts, as well as fungi and bacteria. Therefore, if organic waste (paper, food waste, etc.) completely decomposes after 1-3 years, polymeric materials - after 5-20 years, then glass, like steel, can be preserved without much damage for tens and even hundreds of years.
The volume of unused cullet, according to the Institute of Secondary Resources, amounted to more than 2.5 million tons in 2000. In the Krasnoyarsk Territory alone, more than 1650 tons accumulated in dumps. total.
Many leading research centers in Russia, the CIS countries and abroad have been actively working in the field of cullet recycling in recent years. So, for example, in the USA, 444 million dollars (!) were allocated for research conducted by specialists from the Faculty of Engineering and Applied Sciences at Columbia University (New York State) related to the problem of replacing stone aggregate in concrete with broken glass.
For more than fifteen years at the Moscow State University of Civil Engineering (former MISI) at the Department of Technology of Finishing and Insulating Materials (TOIM), inventors Yu. P. Gorlov, A. P. Merkin, V. Yu. Burov, B. M. Rumyantsev have been developing compositions and technologies for obtaining various types of building materials based on natural and man-made glasses. These materials do not involve the use of traditional binders (such as cement, lime, gypsum) or aggregates and allow complete recycling of cullet.
Created materials with specified adjustable properties can be used in different areas. Firstly, in industrial and civil construction (concrete for various purposes, mortars for exterior and interior work, heat and sound insulation, finishing, landscaping, etc.). Secondly, in the nuclear industry (radiation shielding concrete, non-combustible heat-insulating coatings, etc.). Thirdly, in the chemical industry (special concretes resistant to aggressive environments).
The energy-saving technology for the manufacture of materials based on cullet is extremely simple, does not require special equipment, and allows organizing production on free areas of existing construction industry enterprises without significant capital investments.
After sorting, crushing, grinding and dispersing into fractions, glass can be considered fully prepared for the production of building materials. Broken glass fractions over 5 mm are used in concrete as a coarse aggregate, fine fractions (less than 5 mm) as a fine aggregate (sand), and finely ground powder as a binder.
Since cullet, when mixed with water, does not exhibit astringent properties, in order for the hydration reaction to begin, it is necessary to use an activator in the form of an alkali metal compound. In an alkaline environment, cullet is hydrated with the formation of silicic acids, which, upon reaching certain values ​​of the acidity of the medium, begin to turn into a gel. And the gel, being compacted, solidifies large and small aggregate fractions. The result is a dense, strong and durable silicate conglomerate - glass concrete.
The curing of materials made on the basis of cullet can occur both under normal temperature and humidity conditions at 20°C, and at temperatures of 40-50°C in air-dry conditions, and to give them special desired properties - under conditions of heat and moisture treatment at 85 ± 5°С or at elevated temperatures 300-400°С. Author's certificates and patents have been obtained for the compositions of binder compositions, concrete mixtures, as well as a method for producing porous concrete (AS 1073208, 1112724, application for patent 2001135106).
Glass cullet-based materials meet the relevant requirements of current GOSTs. Moreover, they are not inferior in their general construction and functional properties to modern similar materials based on traditional binders. And in a number of indicators, such as biostability, thermal conductivity, acid resistance, they even surpass them.