The process of producing cement-free concrete by activating aluminosilicate materials to increase the compressive and thermal strength

Abstract

This patent is a process of producing cement-free concrete with slag (alkaline active slag concrete) which is produced through the activation of blast furnace slag using alkaline solutions with specific concentrations and ratios and its combination with sand is known as green concrete that has a high speed of gaining strength, low production heat, reduction of energy consumption and natural resources, and low harmful environmental effects due to the reduction of the amount of CO2 entering the atmosphere, which, along with the process of using recycled slag, can help the environment. The slag is mixed with hydroxide sodium and silicate sodium to increase the concrete's compressive resistance as well as its thermal strength. This process also includes gravel, and naphthalene-based superplasticizers and water. All of these ingredients are determined with a specific ratio after many related experiments on them and through the usage of various laboratory equipment in different temperatures.

Description

The Process of Producing Cement-free Concrete by Activating Aluminosilicate Materials to Increase the Compressive and Thermal Strength

[0001] During the last decade, the environment has become the main concern of human societies. The construction industry is the largest consumer of materials and harvester of materials from the ground, and at the same time, the largest producer of waste, filth, and waste that enters the environment. As a construction material, concrete is the most consumed building material of the century, and from the point of view of environmental protection, it is appropriate to consider the production and consumption of concrete and its constituent materials, the interaction of concrete with the environment during its useful life, and finally, how to destroy concrete and return the materials resulting from destruction. It should be investigated in nature and the environment. Considering the high consumption of concrete and the increasing need for cement production, it seems necessary to pay attention to the harmful environmental effects of this material. One of the solutions to reduce these destructive effects is the production of green concrete which will be explained in the following paragraphs.

[0002] The importance of preserving and maintaining buildings in terms of being among the national capitals of any country is not hidden from any government and society, and this issue is more evident in the case of large and public buildings due to their long-term use and the necessity of their continuous use. Meanwhile, concrete buildings have a special place among buildings because they have unique materials that cannot be restored and recycled in many cases. It has always been the subject of research by engineers and researchers, and therefore activated slag concrete with high heat resistance is considered a very suitable option.

[0003] E04H 7 / 00

[0004] KR1020120095237

[0005] LOW CARBON ENVIRONMENTALLY-FRIENDLY CONCRETE WITHOUT USING CEMENT CAPABLE OF HAVING EXCELLENT STRENGTH

[0006] A low carbon environmentally-friendly concrete without using cement is provided to minimize the generation rate of carbon dioxide by using a blast furnace slag and animal protein blending material and not using Portland cement and chemicals. CONSTITUTION: A low carbon environmentally-friendly concrete without using cement comprises 100 parts by weight of aggregate including sand and silicon dioxide powder, 50-60 parts by weight of powder including blast furnace slag and fly ash, 20 parts by weight of water, and 0.4-0.6 parts by weight of animal nature blending material and 3-5 parts by weight of NaOH. The weight ratio of silicon dioxide powder to sand included in the aggregate is 1:0.64 and the weight ratio of the fly ash to the blast furnace slag included in the powder is 1:0.052.

[0007] The mentioned invention and our claimed one both use blast furnace slag, sand, and sodium hydroxide but in different ratios, also they are environment friendly; our claimed concrete does not contain carbon dioxide and animal protein.

[0008] JP2023038451

[0009] CONCRETE BINDING MATERIAL AND CONCRETE USING THE SAME

[0010] To provide a concrete binding material without using cement at all, capable of removing completely CO2 derived from cement, while maintaining strength and improving resistance to a shrinkage crack, and concrete produced using the concrete binding material.

[0011] Both the mentioned patent and our claimed one conclude blast furnace slag instead of cement but the other ingredients in the mentioned formula are different from ours.

[0012] KR1020170090131

[0013] BINDER COMPOSITION WITHOUT CEMENT

[0014] The present invention relates to a binder composition for concrete, and more particularly, to a binder composition for concrete, which can simultaneously solve the problem of depletion of natural resources and energy and the problems of environmental pollution due to carbon dioxide emission by using as a main ingredient, a blast furnace slag powder, a stainless refining slag powder, biomass fuel ash, anhydrous gypsum, and the like, without using 1 type normal portland cement. The binder composition for concrete according to the present invention comprises, with respect to 100 wt% of the blast furnace slag powder, 5 to 200 wt% of the stainless refining slag powder, 5 to 100 wt% of the biomass fuel ash as a stimulant for strong alkali and sulfate, and 5 to 50 wt% of the anhydrous gypsum.

[0015] This patent comprises blast furnace slag and makes an alkali-active material but the rest of its ingredients differ from ours, and also the method and steps of producing it.

[0016] CEMENT COMPOSITION FOR MANUFACTURING CONCRETE SECONDARY PRODUCT USING SLAG AND METHOD FOR MANUFACTURING CONCRETE SECONDARY PRODUCT USING SAME

[0017] Provided is a cement composition for manufacturing a concrete secondary product including slag. According to the present invention, blast furnace slag is used by part of cement being replaced so that a required strength can be developed even without autoclave curing, and then strength is developed through steam curing. Some of ordinary Portland cement used as a binding material during concrete secondary product production is substituted with blast furnace slag and anhydrite so that the initial setting is improved by ettringite-generating anhydrite being added. Regarding the substitution ratio, the ordinary Portland cement, blast furnace slag (granulated ground blast furnace slag powder: GGBS), and anhydrite(CaSO_4) have a weight mixing ratio of 5:4:1.

[0018] This formula consists of cement and a part of it is slag but our claimed formula is cement-free and the goal is to substitute cement and use blast furnace slag to replace it.

[0019] CN110759695

[0020] Cement-free concrete using rod-milled steel slag tailings as main component and preparation method of cement-free concrete

[0021] The invention discloses cement-free concrete using rod-milled steel slag tailings as a main component. The cement-free concrete comprises the following components in parts by weight: 180-240 parts of the rod-milled steel slag tailings, 20-40 parts of mineral slag micropowder, 4-9 parts of desulfurization gypsum, 10-25 parts of water, and 0.6-1.5 parts of a water reducing agent. The production method includes the following steps: a, performing pretreatment on steel slag: performing preliminary crushing on the hot steel slag produced by converter steelmaking by using a pressure hot stuffing process; b, preparing steel slag aggregate: crushing and thinning the steel slag by two-stage rod mill to make particles with particle sizes of <=10 mm account for 90% or more, performing classification sieving on the produced tailings by using a sieve with a pore diameter of 10 mm, and sending the tailings with a diameter of 10 mm or less to a stirring station as a raw material; c, preparing the desulfurization gypsum: drying block desulfurization gypsum, and performing grinding to form powder for standby application; and d, preparing the cement-free concrete: weighing the prepared steel slag tailings, the mineral slag micropowder and the desulfurization gypsum powder according to the ratio, adding the water reducing agent and the water, performing mixing, and performing uniform stirring to obtain the steel slag ready-mixed concrete without adding cement or sand at all. The method can prepare the qualified concrete without using the cement or the sand at all.

[0022] This patent does not use cement like ours but we use sand while the mentioned formula does not have it, also the other materials in it are not similar to our claimed concrete.

[0023] RU0002811105

[0024] HEAT-RESISTANT SLAG FIBRE CONCRETE

[0025] construction materials. SUBSTANCE: invention relates to special heat-resistant concretes intended for use in conditions of elevated temperatures, as well as low (negative temperatures) environments. Heat-resistant slag fibre concrete is made from a concrete mixture containing Portland cement, aggregate, fibre, filler, superplasticizer, and water. Washed quarry sand and screenings of crushed blast stone sized 0-5 mm, as a fibre - basalt fibre with a fibre length of 1.8-2 cm, as a filler - ground granulated blast furnace slag with a specific surface of 4500 cm2 / g, as a superplasticizer - a superplasticizer based on modified lignosulphonates in the following ratio components, wt.%: Portland cement CEM I 42.5 N - 17.83; washed quarry sand - 25.10; screening of blast furnace crushed stone sized 0-5 mm - 37.07; the specified ground granulated slag - 5.35; basalt fibre - 0.5; the said plasticizer - 0.5; water - 13.65. EFFECT: creation of new structural heat-resistant slag fibre concrete with the properties ensuring heat resistance at temperatures up to 800°C, without loss of concrete strength after 28 days, ensuring cyclic operation of structures exposed to high and low ambient temperatures, as well as their operation under exposure to an aquatic environment, while simultaneously reducing the cost of manufacturing heat-resistant slag fibre concrete through the use of blast furnace slag.

[0026] The mentioned patent and our claimed one are similar in their heat resistance and also usage of slag and plasticizer, but their huge difference is in the Portland cement in the mentioned formula because we totally did not use it and replaced it with blast furnace slag.

[0027] KR101133440

[0028] ENVIRONMENTALLY-FRIENDLY LOESS CONCRETE PAVEMENT MATERIAL, WITH A HUMIDITY CONTROL FUNCTION OF LOESS THAT CAN CONTROL TEMPERATURES OF ROAD SURFACES

[0029] An environmentally-friendly loess concrete pavement material is provided to prevent a pavement layer from being broken because water can easily drain and penetrate in the pavement layer and a pavement material has excellent binding property. CONSTITUTION: An environmentally-friendly loess concrete pavement material is composed as follows. Aggregate, broken sand, shore sand, loess power, pigment, and water are mixed with predetermined ratio without using cement. A constant proportion of a stimulant is added to cure in the room temperature. The stimulant is composed of an inorganic binder, a metakaolin, and a silica. The inorganic binder is composed of recycled industrial byproducts such as a blast furnace slag. The metakaolin supplements binding force of a loess concrete. The silica allows molded property of the loess concrete to improve.

[0030] The mentioned patent is cement-free and uses slag, sand, and water like our mentioned patent but we did not use sodium aluminum cells, gypsum, and quicklime.

[0031] KR1019424250000

[0032] ECO-FRIENDLY POLYMER MORTAR COMPOSITION FOR REPAIRING CONCRETE STRUCTURE WITHOUT PORTLAND CEMENT AND METHOD FOR REPAIRING CONCRETE STRUCTURE USING SAME

[0033] The present invention provides an eco-friendly polymer mortar composition for repairing a concrete structure without Portland concrete and a method for repairing a concrete structure using the same, which largely lowers manufacturing costs by using blast furnace slag, has rapid curing speed, enhances initial strength and long term strength, and minimizes generation of hexavalent chromium (Cr^6+), a harmful substance, by excluding Portland concrete. The eco-friendly polymer mortar composition for repairing a concrete structure without Portland concrete contains: 49-55 wt% of blast furnace slag cement; 0.05-0.2 wt% of fiber; 0.2-1.5 wt% of polymer; 0.02-0.1 wt% of a thickener; 0.05-0.2 wt% of a foaming agent; and 40-50 wt% of fine aggregate wherein the blast furnace cement contains the blast furnace as a maximum constituent with respect to weight and also contains hauyne, lime and anhydrous gypsum to be able to generate ettringite (3CaO middot;Al_2O_3 middot;3CaSO_4 middot;32H_2O) through hydration.

[0034] This mentioned concrete is cement-free and environmentally friendly, it also includes slag but most of it is fiber and polymer because it focuses on repairing concrete but in our invention, we focus on producing concrete from the beginning.

[0035] WO1999007650

[0036] ALKALINE SULFOALUMINOSILICATE HYDRAULIC CEMENT AND PROCESS FOR ITS MANUFACTURE

[0037] An alkaline sulfoaluminosilicate hydraulic cement contains water, calcium magnesium aluminosilicate glass, portland cement clinker, sinter made from sodium zeolite and an SO42--containing component, metakaolin and alkali metal compounds. Used as zeolites may be either synthetic zeolite and zeolite-containing rock in which the main rock-forming minerals are clinoptilolite, mordenite, gmelinite and analcime. Used as a SO42--containing component is a technical product, Na2SO4 or natural raw materials, by-products or alumino-potassium alums. The sinter is obtained by thermal activation in the temperature range 500° to 800 °C of sodium zeolite and SO42--containing component taken in a ratio ranging between 1:1 to 4:1. A bonding matrix obtained from the alkaline sulfoaluminosilicate hydraulic cement upon mixing with water comprises alkaline sulfoaluminate and sulfoaluminosilicate phases. The concrete composition exhibits high sulfate resistance, stable strength characteristics under alternate wetting-drying as well as low shrinkage along with high compressive strength and rapid strength gain.

[0038] The aluminosilicate and blast furnace slag are similar to our claimed formula, but the other ingredients used in this mentioned formula cannot be found in ours because we used sand, gravel, water, and superplasticizer.

[0039] The process involves producing cementless concrete by activating aluminosilicate substances to enhance thermal resistance and compressive strength. The materials used include blast furnace slag, sodium hydroxide, sodium silicate, superplasticizer, and stone materials (sand and gravel). The mixing plan specifies the weight ratios and concentrations of the materials used, as well as the processing temperature. The process includes mixing the aggregates, adding an alkaline solution, water, and superplasticizer, and filling molds for curing.

[0040] Concrete is the most important and widely used building material produced by human hands, which has advantages such as easy formability and moldability, suitable fire resistance compared to wood and steel, better stability against atmospheric factors, convenient production, and finally, being cheap. It has made this material well received. In 1991, 3 billion tons of concrete, equivalent to half a ton per person, were consumed in the world. The only substance that humans consume to this extent is water. According to some studies, about 12,000 million tons of concrete are made annually, and about 1,600 million tons of cement are used in the world. On the other hand, Portland cement production has many environmental problems. A significant amount of energy is consumed in the cement production process, so about 5% of the industrial energy consumed in the world is related to the cement industry, and 1700 to 1800 megajoules of energy are consumed to produce each ton of clinker. In the cement production process, 125 liters of fossil fuel and 118 kilowatt hours of electricity are consumed on average. On the other hand, 11.9% of the country's road cargo is dedicated to cement. In addition, approximately 1.5 tons of raw materials are needed to produce one ton of cement. In addition, from the production of each ton of cement, as well as due to the burning of fuel oil and electricity consumption in cement factories, approximately 0.94 tons of carbon dioxide gas is produced and enters the environment. According to the International Energy Organization (IEA), between 6 and 7 percent of the total CO2 produced in the world is related to the cement industry. Therefore, considering the high consumption of concrete and the increasing need to produce cement for its preparation, the importance of environmental issues and especially attention to the issue of (sustainable development) in the concept of (optimal use and correct and efficient exploitation of basic resources, natural resources, etc.) In order to meet the needs of the current and future generations, the need to review concrete production and research in relation to the use of new technologies for concrete production has become more apparent.

[0041] Fire is one of the most dangerous phenomena that a structure may encounter during its lifetime. The heat caused by a fire causes changes in the physical and mechanical characteristics of concrete, including mass reduction, cracks and spalling on the surface of concrete. The reduction of mechanical properties (compressive strength, tensile strength and modulus of elasticity). In general, when talking about heat resistance, it is meant to maintain strength and not cause spalling with high destruction intensity in the concrete sample after being exposed to heat. So In order to evaluate the resistance of concrete against heat, various parameters such as thermal and mechanical properties and special properties such as flaking and reduction of concrete mass should be investigated, all of these properties at high temperatures are related to the mixing plan, type of aggregate, processing conditions and conditions. Since heat resistance plays a decisive role in the operation level and performance of the structure, it is necessary to investigate the effect of heat on the performance of concrete and the construction of concrete with high heat resistance in these conditions.

[0042] The performance of conventional concrete against high temperatures has been extensively investigated and its characteristics are well established. The loss of strength of ordinary concrete is due to physical and chemical changes in the microstructure of concrete caused by changes in hydration products. At temperatures up to 300°C, small cracks can be seen on the surface of concrete, and the width of these cracks always increases with increasing temperature. At a temperature above 400 ˚C, calcium hydroxide (CaOH2), which forms a major part of the hydration products, is decomposed into other products. In addition, calcium silicate gel (C-S-H) which is known as the main component of cement paste and the main factor of concrete strength is decomposed at 600 ˚C. This decomposition of hydration products is intensified at a temperature of about 800˚C, which results in the complete destruction of the concrete structure and its material properties.

[0043] According to the explanations given, one of the basic goals of this invention is to make concrete, which, in the first place, reduces the environmental hazards of ordinary concrete by removing cement as an adhesive material and using slag instead, and on the other hand, in addition to environmental approaches According to the technical and economic considerations, this large volume of slag depots in the country's steel factories should be used to the maximum and optimally and move in the direction of sustainable development. On the other hand, according to the factors affecting the mixing plan of this type of concrete, two important characteristics, i.e. compressive strength and thermal resistance of this concrete, should be significantly increased compared to ordinary concrete.Solution of Problem

[0044] During the last decade, the environment has become the main concern of human societies. The construction industry is the largest consumer of materials and harvester of materials from the ground, and at the same time, the largest producer of waste, filth and waste that enters the environment. On the other hand, concrete is the most widely used building material as a building material of the century. The issue of the environment in the concrete industry has received more attention in recent years and after the Rio Declaration, which was approved by 179 countries. Improving the quality and durability of concrete, along with its resistance, was considered at the annual conference of the American Concrete Association in 2001 as a new paradigm in the construction industry. To investigate the environmental performance of concrete, the problem of production and consumption of cement, water, aggregates, additives, concrete structures and materials resulting from the destruction of these structures and the positive and negative physical and chemical effects of each of them on the environment, including pollutants that They enter the earth's atmosphere, soil and water, the protection they provide for the continuation of human life on the planet and the material and spiritual well-being they create for human life, work and growth are studied. In this regard, in recent years, the use of green concrete has become very popular in many countries. This innovative concrete can be produced using waste materials as one of its components. Also, green concrete can be produced using different production processes, which are not harmful to the environment. The criteria for green concrete is that the materials used to make it must be from "green" or sustainable materials instead of non-sustainable sources. The use of recycled materials and waste materials can be considered as sustainable resources if they can reduce the costs and consumption of raw materials and also reduce the level of landfill. One of the ways to produce green and environmentally friendly concrete is to reduce the consumption of ordinary Portland cement and the negative effects associated with its production. Therefore, replacing part of the cement used in concrete with pozzolanic materials such as metakaolin and fly ash, or cementitious materials such as blast furnace slag seems to be a suitable solution. The mentioned pozzolanic and pseudo-cement materials are a suitable alternative to many types of Portland cement because the raw materials used to produce these materials are easily accessible. Also, the production temperature range of most of them is much lower than conventional cement, and for this reason, the release of pollutants such as CO2 caused by cement kilns is prevented. Geopolymers are a new type of adhesive material to replace Portland cement, which are produced from the reaction of aluminosilicate materials with an alkaline solution, and lead to the production of a type of concrete called geopolymer concrete, which can be considered as a scientific and practical solution to replace concrete with ordinary Portland cement. be taken Among the substitute materials for cement, materials such as metakaolin and fly ash have become common materials for the production of geopolymers due to their high percentage of alumina and silica and their easy access to waste disposal sites. Among the other advantages of pozzolanic and pseudo-cement materials, in addition to reducing cement consumption and being economical, we can mention the reduction of the speed and amount of heat of dehydrating, increasing the strength of concrete and increasing the reliability of concrete by reducing its permeability. Meanwhile, slag has received more attention due to its high percentage of calcium (CaO), which makes it chemically similar to ordinary Portland cement. So that the conducted research shows that it can be completely replaced with cement. Unlike other pozzolans that react with calcium hydroxide (CaOH2) resulting from cement hydration and consume it, slag uses calcium hydroxide only as a catalyst and has a cement-like reaction in the presence of water, with the difference that it is due to Its reaction does not produce calcium hydroxide. Due to its hidden hydraulic property, slag cannot be activated by itself and needs an activator. When slag is used as a pozzolan, replacing a part of cement, after the decomposition of anhydrous compounds of cement into its constituent ions, the alkalinity of the solution increases and this causes the activation of slag. When slag is combined with water alone, it breaks down into fine particles and forms an ineffective protective layer of Ca2+ that prevents further reactions from proceeding. If the pH of the mixture is kept high enough, this protective layer is broken and the reactions continue. Therefore, to completely replace it with cement, an alkaline solution is needed as an activator. In fact, the role of alkalis in this concrete is to keep OH¯ ions high in the mixture. Considering that the cost of metakaolin is high in Iran and fly ash is considered an imported product, there is practically no production of geopolymer concrete in Iran. However, with the presence of slag in Iran, especially in Isfahan, it is possible to produce cementless concrete with slag (alkaline active slag concrete).

[0045] Research on alkali-active concrete shows that compared to normal concrete, it exhibits high mechanical resistance and also good performance against chemical attacks, and freeze and thaw cycles. Its permeability and hydration heat production rate is also lower than normal concrete. According to the technical and economic considerations and considering the harmful environmental effects of cement production, slag-activated alkali concrete can be used as a substitute for normal concrete because the destructive effects of slag-activated alkali concrete are about 70% less than normal concrete and the amount of energy consumption in The production of this concrete is 60% less than normal concrete. Of course, slag-activated alkaline concrete, like ordinary concrete, despite all the advantages mentioned, also has disadvantages. Low tensile strength (like normal concrete) and high shrinkage are the weak points of this concrete.

[0046] Cement substitute material:

[0047] Cement substitutes include pozzolans and cementitious materials. These materials are used to reduce cement consumption, the speed and amount of heat of dewatering, and Increase the strength of concrete and the reliability of concrete by reducing its permeability, they are also economical.

[0048] The claimed concrete comprises the following components:

[0049] 1- Slag

[0050] According to the standard definition of ASTM C989M-13, blast furnace slag is a non-metallic compound that contains calcium silicates aluminosilicates, and other basic elements and is produced in a molten form in a blast furnace along with iron. Steel slag is a non-metallic compound that contains calcium silicates, calcium ferrites, and iron, aluminum, manganese, calcium, and magnesium oxides and is produced simultaneously with steel.

[0051] What distinguishes slag from other pozzolanic materials such as metakaolin and fly ash is its high percentage (38-44%) of calcium CaO, which makes it chemically similar to ordinary Portland cement. When the environment is suitable, the chemical and non-crystalline compounds of slag react with water, and this reaction is similar to the hydration of cement. The intensity of these reactions depends on the chemical composition of the slag, the amount of crystallinity and the softness of the slag. In other words, slag alone can be used as cement, but this requires the activation of the cementitious property of slag by an alkaline solution with a high pH. Based on this, a new generation of cement materials called slag-activated alkali cements was formed, and the concrete produced from this type of cement was named as slag-activated alkali concrete. Slag is the main binder material in active alkali concrete. Blast furnace slag (in the form of granules) is prepared in a ground form for this process.

[0052] The result of XRF chemical analysis of the used slag is given in Table 1.

[0053] 2- Sodium hydroxide (NaOH)

[0054] Sodium hydroxide or caustic soda or caustic soda with the chemical formula NaOH is a white solid substance with a density of 2.13 grams per cubic centimeter and a molar mass of 40 grams per mole. This material can easily absorb moisture from the air and for this reason, it should be covered with protective covers during transportation. Sodium hydroxide produces a strong alkaline solution in water, that is, in water, it is completely separated into its constituent ions, i.e., Na+ and OH-. As a strong base, this substance is considered one of the most important industrial chemicals.

[0055] To prepare a sodium hydroxide solution with a specific concentration (molarity), considering that the molar mass of sodium hydroxide is 40 grams / mol, the amount of sodium hydroxide dissolved in one liter of solution is equal to 40 times the molarity. For example, to prepare a solution with a concentration of 6 M, the amount of 6 x 40 = 240 grams of solid sodium hydroxide is poured into a graduated cylinder and by adding water, we bring the volume of the solution to one liter. Since the reaction of sodium hydroxide with water is an exothermic reaction and significant heat is produced while it dissolves in water, it is better to place the cylinder containing the solution in a basin of cold water to prevent the evaporation of the water in the solution.

[0056] 3- Sodium silicate (Na2SiO3)

[0057] Sodium silicate is the general name of sodium metasilicate or Na2SiO3 and is also known as "water glass" or "liquid glass". This material is a combination of sodium oxide (Na2O) and silica (SiO2) which can be prepared in different ways and with different purity. Each of these characteristics has a unique chemistry and has its own industrial and consumer applications. This product is available as an aqueous and solid solution and is used in various industries, for example, in concrete industries and construction activities, it is widely used as a plasticizer and increasing the amount of resistance against water penetration.

[0058] One of the important characteristics in determining the use of sodium silicate types in various industries is the ratio of silica to soda. The higher this ratio is, the higher the density of sodium silicate will be. The sodium silicate used in this research is a product of Nafis Silicate Company with the chemical composition presented in Table 2.

[0059] 4- Concrete Plasticizer Additive

[0060] The ASTM C125 standard defines an additive as a substance other than water, aggregate, hydraulic cement, and reinforcing fibers that are used as a component of concrete or mortar and are added to the measure before or during mixing Superplasticizer (strong water reducer) is considered one of the most widely used types of additives according to the ASTM C494 standard In this process, a naphthalene-based superplasticizer with chemical analysis according to [Table 3] is used.

[0061] Stone materials are filler materials that do not react with cement and occupy about 75% of the concrete’s volume. These aggregates can have a significant effect on the strange , dimensional stability, and durability of concrete.

[0062] The following tests have been performed on all the stone materials used in this process:

[0063] 1- Granulation of stone materials - ISIRI 4977, ISIRI 302 standard

[0064] 2- Saturated grain density and determination of water absorption of stone materials - ASTM C127, ASTM C128 standard

[0065] 3- Moisture percentage of stone materials - ASTM C566 standard

[0066] 4- Passing percentage of ISIRI score 200- 302

[0067] 5- Modulus of softness (FM) of sand - ISIRI 302

[0068] 6- Sand value (SE) - ISIRI 302 standard

[0069] Stone Materials:

[0070] Sand and gravel:

[0071] In these guidelines, broken mountain sand, whose granularity is within the permissible limits recommended in ASTM C33 and ISIRI 302 standards, has been used.

[0072] Sand has the role of filling between coarse-grained material and must be free of any pollution and mud. The modulus of softness of sand used in concrete should be in the range of 2.3 t0 1.3, table 4 shows the physical characteristics of the sand. Granulation of the prepared sand was done using standard sieves. The humidity percentage of the sand has been controlled and measured before the construction and it is considered in the calculation of the mix design.

[0073] The maximum size of coarse grains is determined based on the type of work for this process, and shattered aggregates with a maximum dimension of 19 millimeters have been used. Table 6 shows the physical characteristics of the gravel with dimensions between 4.75 and 12 millimeters, and the second type ranges from 12 to 19 millimeters.

[0074] Concrete Mix Design:

[0075] Slag active alkali concrete mixing design method for a design with 400 kg of slag per cubic meter of concrete, weight ratio of solution to slag 0.5, weight ratio of sodium hydroxide to sodium silicate 1, soda 6 M, ratio of fine to coarse grain 1, water ratio 0.35% solids and 1% slag lubricant are given in the examples section.

[0076] Laboratory Equipment

[0077] 1- Weight and Volume Measuring Devices

[0078] In order to measure the weight of materials and concrete samples, two types of scales with different capacity and accuracy have been used.

[0079] - A scale with an accuracy of 0.1 grams to measure the weight of materials up to 3 kg, which is mostly used to weigh the amounts of water, super-lubricant, alkaline solutions and to test the measurement of moisture and density of aggregates.

[0080] - A scale with an accuracy of 5 grams for weighing materials up to a maximum of 15 kg, which was mostly used for weighing large amounts of aggregate in a high mixture volume, grading materials, and performing concrete weight tests and concrete sample mass

[0081] - In order to measure the volume, different volumetric containers were used to test the specific gravity of fresh concrete, specific gravity, and water absorption of fine aggregates (sand).

[0082] 2- Mixer machine

[0083] The purpose of mixing concrete components is to uniformly cover the aggregates with the paste made of cement materials. This research used a mixer with a nominal capacity of 250 liters and a horizontal tank to make slag-active alkali concrete.

[0084] 3- Concrete Mold

[0085] In these instructions, to perform the compressive strength test according to the BS standard, a 150x150x150 mm cube sample was used, and a 100x200 mm cylindrical sample was used for the tensile strength test. The molds used are made of metal.

[0086] 4- Slump Cone

[0087] According to the ASTM C143 standard, in the slump test, an incomplete metal cone with a height of 302 mm (12 inches) a base diameter of 203 mm (8 inches), and a smaller base diameter at the top of 102 mm (4 inches) is used.

[0088] 5- Heat Treatment Furnace

[0089] This device has a maximum heat production capacity of 1100 ˚C with gas fuel, has a completely thermally insulated body, and is equipped with a high-precision thermocouple device (thermocouple to show the internal temperature of the furnace) for heating cubic and cylindrical samples at temperatures of 200, 400, 600 and 800 °C were used. The heating rate of this device can be adjusted according to the amount of fuel reaching the burner of the furnace.

[0090] 6- Concrete Breaker Jack

[0091] To determine the compressive strength of cubic samples and the tensile strength of cylindrical samples using the demonization (Brazilian) method, a loading device (hydraulic jack) with a maximum power generation capacity of up to 200 tons has been used. The upper part of the device consists of a digital display that shows the force applied to the sample. After placing the sample on the lower jaw of the device and turning it on, the lower jaw starts moving and approaches the upper jaw. The upper jaw can rotate to some extent and align itself with the upper surface of the sample The load should be applied vertically to the entire surface of the sample.

[0092] How to mix and make slag-active alkali concrete samples;

[0093] Based on the studies, researchers have used different methods for mixing and making active alkali samples, which are very similar to each other. In the claimed process, the following method was used for mixing concrete:

[0094] 1- First, the aggregates (sand and gravel) are mixed with each other in a dry form using a mixer.

[0095] 2- After adding slag, dry materials are mixed for 3 minutes.

[0096] 3- An alkaline solution consisting of sodium hydroxide and sodium silicate is gradually added to the mixture and then water is added.

[0097] 4- At the end, naphthalene super lubricant is added and all the materials are mixed together for 4 minutes.

[0098] 5- Cubic and cylindrical molds are filled in two layers and each layer is beaten with 25 blows.

[0099] 6- The filled molds are placed at room temperature for 24 hours and then the samples are removed from the mold and placed inside the water basin for processing.

[0100] In general, the results of the research conducted on this concrete are as follows:

[0101] 1- The specific weight of fresh concrete with active slag alkali is lower than normal fresh concrete with Portland cement.

[0102] 2- In activated alkali slag concrete, by increasing the amount of slag and keeping the rest of the influencing factors constant in the mixing plan of this type of concrete, such as the ratio of alkaline activators to slag, the ratio of sodium hydroxide to sodium silicate, the ratio of water to solids and the percentage of lubricant. consumption, the compressive strength increases.

[0103] 3- The compressive strength of slag active alkali concrete is higher than the compressive strength of normal concrete with Portland cement with the same mixing design. So the compressive strength of activated alkali slag concrete at the age of 28 and 90 days is approximately 1.15 and 1.5 times the compressive strength of normal concrete at the age of 28 days.

[0104] 4- The growth of the compressive strength of active alkali slag concrete from the age of 1 to 7 days and the age of 28 to 90 days is high compared to the age of 7 to 28 days, which is due to the rapid initial setting and long final setting of this type of concrete.

[0105] 5- According to the comparison of the tensile strength of slag-active alkali concrete with normal concrete at the age of 28 days, it is observed that the tensile strength of slag-active alkali concrete is lower than normal concrete with Portland cement with the same mixing plan. In such a way the tensile strength of normal concrete is approximately 1.2 times that of slag-active alkali concrete.

[0106] 6- As the temperature increases, the percentage of mass reduction of the samples increases. The percentage of mass reduction depends on the geometric shape of concrete samples so cylindrical samples experience more mass reduction than cubic samples at similar temperatures.

[0107] 7- The mass reduction percentage of slag active alkali concrete due to temperature increase is lower than normal concrete with Portland cement. The mass reduction percentage of cubic and cylindrical samples of slag-active alkali concrete is about 2% and 10% less than normal concrete, respectively.

[0108] 8- As the temperature increases, the compressive strength of concrete decreases. By increasing the temperature to 800°C, the compressive strength of slag active alkali concrete has decreased by 70% and the compressive strength of normal concrete with Portland cement has decreased by 90%.

[0109] 9- As the temperature increases, the tensile strength of concrete decreases. With the increase in temperature up to 800°C, the tensile strength of slag-active alkali concrete has decreased by 88% and the compressive strength of normal concrete with Portland cement has decreased by 100%.

[0110] 11- The probability of cracking increases in all samples while the temperature increases, the results of the electron microscope (SEM) imaging show that with the increase in temperature, cracks have been created inside the C-S-H gel, and the development of these cracks will cause the complete rupture of the C-S-H gel and thus reduce the compressive and tensile strength of concrete.

[0111] 12- The thermal resistance of slag-active alkali concrete is more than normal concrete with Portland cement and slag-active alkali concrete has a very good performance against heat.

[0112] 13- By increasing the amount of adhesive paste, the residual compressive and tensile strength is higher with increasing temperature in both types of concrete.Advantage Effects of the Invention

[0113] 1- Cement-free concrete with slag (alkaline active slag concrete) can be used as a substitute for ordinary concrete and reduce the harmful environmental effects caused by cement production.

[0114] 2- The destructive effects of slag-activated alkali concrete are about 70% less than normal concrete and the amount of energy consumption in the production of this concrete is 60% less than normal concrete.

[0115] 3- In slag active alkali concrete, considering that slag is a by-product of the steel industry as an adhesive, it is more economical than normal concrete.

[0116] 4- According to the researchers' findings, the use of slag reduces the permeability and thus increases the durability of concrete.

[0117] 5- This cement-free concrete made with blast furnace slag, according to the results of the tests, has a much higher compressive strength than ordinary concrete and also has a suitable tensile strength.

[0118] 6- This cement-free concrete made with blast furnace slag, according to the results of the tests, has a much higher thermal resistance than ordinary concrete.

[0119] 7- According to the mentioned advantages of this invention, in addition to being compatible with the environment, it can be a very suitable alternative to ordinary concrete and meet many of the needs of the construction industry today.

[0120] ] Shows a flowchart of the concrete’s production process.

[0121] presents a flow chart of the steps of producing the cement-free concrete from the beginning and each ingredient’s amount of usage until the end in addition to the final total weight.Examples

[0122] One of the implementation methods of this invention is to make this concrete with concrete mixers with a capacity of at least 250 liters and to make various prefabricated parts such as beams, tables, New Jersey concrete separators, electric poles, etc.

[0123] There have been several experiments and analyses done for the final formula of the claimed cement-free concrete and according to the given explanation in the solution section, the following tables are related to the mentioned chemical analysis and research.

[0124] [Table. 1] is the result of the chemical analyse (XRF) of the blast furnace slag:

[0125] In the DIN 1164 standard for slag, the following formula is stated; So this ratio must be more than 1, which has been observed for the slag according to the above table.

[0126]

[0127] [Table. 2] shows the chemical compound of the silicate sodium used in the claimed concrete:

[0128] [Table. 3] presents the chemical analysis of the naphthalene-based superplasticizer:

[0129] [Table. 4] shows the physical features of the used sand in the claimed process:

[0130] [Table. 5] The granularity of the consumed sand:

[0131] As can be seen from the results of the above tables, the sand used in this process has very good granulation, softness modulus, and sand value, and there is no need to modify the granulation.

[0132] [Table. 6] The physical features of the consumed gravel in the production of the concrete:

[0133] [Table. 7] shows the granularity of the consumed gravel from 4 / 75 to 12 mL:

[0134] [Table. 8] shows the granularity of the consumed gravel from 12 to 19 mL:

[0135] [Table. 9] presents the amount of each ingredient used in the claimed process and their factors:

[0136] Mathemathical explanation of the slag active alkali concrete mix design in the form of an example:

[0137] For instance, the slag active alkali concrete mixing design method for a design with 400 kg of slag per cubic meter of concrete, weight ratio of solution to slag 0.5, weight ratio of sodium hydroxide to sodium silicate 1, sodium 6 M, ratio of fine to coarse grain 1, the ratio of water to solids is 0.35 and superplasticizer is 1% of slag as shown below.

[0138] 1) The amount of slag consumed per cubic meter of active alkali concrete is considered:

[0139] Slag = 3400 kg / m

[0140] 2) Considering that the weight ratio of the activating alkaline solution to the slag is equal to 0.5, then we have:

[0141] Activating alkaline solution = 0.5 × 400 = 3200 kg / m

[0142] 3) Because the weight ratio of sodium hydroxide solution to sodium silicate is equal to 1, therefore:

[0143] Sodium hydroxide solution = 100 kg / m3

[0144] Sodium silicate solution = 100 kg / m3

[0145] 4) considering that sodium hydroxide is solid and its 6 M solution should be prepared, we have:

[0146] The molar mass of sodium hydroxide = 40 g / m

[0147] So, in one liter of 6 M sodium hydroxide solution, 6 x 40 g240 of solid sodium hydroxide has been used.

[0148] Specific weight of sodium hydroxide solution = 2.13 g / cm3

[0149] Volume of 240 grams of sodium hydroxide = 0.113 lit = 2.13 ÷ 240

[0150] Volume of added water = 0.887 lit = 0.113 - 1

[0151] Therefore, the mass of one liter of 6 M sodium hydroxide solution is 1127 grams. So, 213 grams of solid sodium hydroxide and 787 grams of water are used in one kilogram of this solution.

[0152] Sodium hydroxide solution = 3100 kg / m, sodium hydroxide = 21 / 33 kg / m and water = 78 / 37 kg / m

[0153] Because sodium silicate is prepared as a solution with a purity of 54%, we have:

[0154] Sodium silicate solution (54%) = kg / m3100, sodium silicate = kg / m354 and water = kg / m346

[0155] Now, considering the ratio of water to solids, we have 0.35:

[0156] Water = 0.35 x (slag + sodium hydroxide + sodium silicate) = 166.336 kg / m Pure water = 41.366 kg / m

[0157] The volume of concrete paste is obtained as follows:

[0158] Specific gravity of slag = 2.8 g / cm3

[0159] Specific weight of sodium hydroxide solution = 2.13 g / cm3

[0160] Specific weight of sodium silicate solution = 2.4 g / cm3

[0161] Dough volume = lit72 / 341 = (1÷ 36 / 166)+ (4 / 2÷ 54)+ (2 / 13÷ 3 / 21)+ (8 / 2÷ 400)

[0162] If we assume that 2% of the total volume of concrete is made up of air bubbles, that means 20 liters of air bubbles in one cubic meter. So the volume of stone materials and its mass will be equal to:

[0163] Volume of stone materials = 28 / 638 lit = 980-341-72

[0164] Assuming that the specific weight of all stone materials is 2.365 g / cm, we have:

[0165] Total weight of stone materials = 1691 / 344 kg / m

[0166] Weight of sand (50%) = 845 / 372 kg / m

[0167] The weight of sand is 4.75-12 (30%) = 507.343 kg / m

[0168] Weight of sand 12-19 (20%) = 338 / 329 kg / m

[0169] Naphthalene superplasticizer is used at the rate of 1% by weight of slag:

[0170] Naphthalene superplasticizer = 1% slag = kg / m34

[0171] Total weight of concrete materials = 2333 / 31 kg / m

[0172] In this process, considering the effective and controllable factors in the production of slag-activated alkali concrete, a suitable and optimal mixing plan was considered for making this type of concrete. Table 10 shows the mixing plan of active alkali concretes made with slag. The mixing plans for one cubic meter of slag-activated alkali concrete are mentioned, and it means the ratio of water to total solids, ratio of water to total slag, solid sodium hydroxide and solid sodium silicate. As it is clear from the mixing plans, only the amount of slag changes and the rest of the parameters are changing based on the amount of slag per cubic meter.

[0173] [Table. 10] shows the mixing design of the slag active alkali for the experiments:

[0174] This invention will be very widely used to replace regular concrete with Portland cement, produce prefabricated concrete parts, repair concrete parts, and make concretes that are exposed to highly sulfated environments and in tall buildings where high pressure and thermal resistance are very important.

Claims

A process of producing cement-free concrete by activating the aluminosilicate substances to escalate the thermal resistance and compressive strength using the following materials:1- Blast furnace slag2- Hydroxide sodium3- Silicate sodium5- Superplasticizer6- Stone materials (sand and gravel)According to claim 1, for the mixing plan of this concrete, the weight ratio of solution to slag is 0.5, the weight ratio of sodium hydroxide to sodium silicate is 1, the concentration of sodium hydroxide solution is 6 M, the ratio of fine grains to coarse grains is 1, the ratio of water to solids is 0.35, the weight percentage of liquid 1 percent of slag and the processing temperature is set at 20°C.According to Claim 2, first the aggregates (sand and gravel) are mixed dry in a mixer until the slag is added and mixing continues for three minutes.According to claim 3, an alkaline solution composed of sodium hydroxide and sodium silicate is gradually added to the mixture.According to claim 3, the water is added followed by naphthalene superplasticizer, then they get mixed for four minutes.According to claim 5, the cubic and cylindrical molds are filled in two layers and each is beaten with 25 blows.According to claim 6, the samples will be extracted from the mold after 24 hours of being at room tempreture, then they will be put in the basin for curing.

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