DE202024100121U1 - Composition and system for controlling the compressive strength of geopolymer concrete based on fly ash and slag: binder index - Google Patents

Abstract

Composition for controlling the compressive strength of fly ash and slag through a geopolymer concrete: binder index, the composition comprising:
a geopolymer concrete such as fly ash and ground granulated blast furnace slag (GGBS);
an alkaline activator solution; and
a variety of aggregates.

Description

FIELD OF THE INVENTION

The present invention relates to the field of structural engineering systems. More particularly, the present invention relates to a composition and system for producing and controlling the compressive strength of optimized geopolymer concrete: binder index approach.

BACKGROUND OF THE INVENTION

The steep rise in infrastructure development has led to huge consumption of various construction materials such as cement. During the production of cement, high CO ₂ emissions are released into the atmosphere, which leads to an imbalance in the environment and causes the greenhouse effect and the depletion of natural resources. In order to reduce these negative impacts on the atmosphere, various environmentally friendly building materials have been developed around the world that reduce the excessive use of new materials in the production of concrete, such as: B. the replacement of traditional Portland cement (OPC) with large amounts of additional cementitious materials or binders rich in silica and alumina, such as. E.g. fly ash, rice husk ash, ground granulated blast furnace slag (GGBS), metakaolin, etc.

However, the use of geopolymer concrete is severely limited due to a lack of research into structural elements, design and applications. The properties of geopolymer concrete under various structural actions such as compression, tension, bending, shear, etc. are not explored in the literature. The effective use of these binders such as fly ash and ground blast furnace slag in concrete production reduces landfill pressure and environmental pollution. Conversely, reducing the OPC content in concrete reduces the ability to activate the binder.

In the recent past, several studies have reported various parameters affecting the strength of GPC. The concentration of sodium hydroxide plays a role in varying the strength of GPC. The effects of various parameters, such as the amount of starting material, the ratio of activator to binder and the molarity of the activator solution, on the strength of GPC are very different. To study the combined effect of different parameters on the strength of GGBS- and FA-based GPC, a new parameter called ‘binder index (Bi)’ is proposed. However, the previously proposed binder index did not take into account the variation of alkali to binder ratio.

Despite the advantages, the use of geopolymer concrete in practice is very limited. This is mainly due to a lack of research into structural elements, design and applications. The use of geopolymer concrete as structural concrete requires studies on its behavior under various structural actions such as compression, tension, bending, shear, etc. Furthermore, there is no single unified parameter but multiple parameters that can be used for controlling the strength of GPC. In many studies, data for controlling strength parameters were adopted from the literature. There are few studies on quantifying the parameters of fly ash and GGBS based geopolymer concrete to observe the performance of strength parameters. There are few studies on the applicability of the existing design theories and design rules for conventional concrete to predict fly ash and GGBS based GPC.

Therefore, in order to overcome the above limitations, there is a need to develop a composition and system for the preparation and control of the compressive strength of optimized geopolymer concrete: binder index approach and the evaluation of the single uniform parameter instead of multiple parameters GPC can be used in controlling strength.

The technical advances disclosed by the present invention overcome the limitations and disadvantages of existing and conventional systems and methods.

SUMMARY OF THE INVENTION

The present invention relates generally to a composition and system for producing and controlling the compressive strength of optimized geopolymer concrete: binder index approach.

The aim of the present invention is to provide a system for preparing and controlling compressive strength.

Another object of the present invention is to conduct an analytical study on the parameters affecting the strength of fly ash and GGBS based geopolymer concrete and to establish unique parameters controlling the strength of GPC.

Another aim of the present invention is to develop a new parameter for measuring various parameters of geopolymer concrete.

Composition for controlling the compressive strength of geopolymer concrete based on fly ash and slag: binder index, the composition comprising: a geopolymer concrete such as fly ash and ground granulated blast furnace slag (GGBS); an alkaline activator solution; and a variety of additives.

System for controlling the compressive strength of geopolymer concrete based on fly ash and slag: binder index, the system comprising: a collection unit for collecting at least one binder rich in silica and alumina for geopolymer concrete; a beaker connected to the collection unit for preparing an alkaline activator solution by mixing sodium hydroxide (NaOH) and sodium silicate (Na ₂ SiO ₃ ); and a reactor connected to the cup and the collection unit to perform geopolymerization of the binder and the produced alkaline activator solution to form optimized complex polymers.

In order to further illustrate the advantages and features of the present invention, a more detailed description of the invention will be made by reference to specific embodiments thereof shown in the accompanying drawings. It is understood that these drawings show only typical embodiments of the invention and therefore should not be considered as limiting its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

• zeigt ein Blockdiagramm eines Systems zur Kontrolle der Druckfestigkeit von Geopolymerbeton auf der Basis von Flugasche und Schlacke: Bindemittelindex, und
• zeigt die Variation der Druckfestigkeit von GPC (fgpc) mit dem vorgeschlagenen Bindemittelindex (Bi).

These and other features, aspects and advantages of the present invention will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters represent like parts throughout the drawings, in which:

• shows a block diagram of a system for controlling the compressive strength of geopolymer concrete based on fly ash and slag: binder index, and
• shows the variation of compressive strength of GPC (fgpc) with the proposed binder index (Bi).

Those skilled in the art will understand that the elements in the drawings are shown for convenience and are not necessarily drawn to scale. For example, the flowcharts illustrate the method through key steps to enhance understanding of aspects of the present disclosure. In addition, one or more components of the device may be represented in the drawings by conventional symbols, and the drawings show only the specific details relevant to understanding the embodiments of the present disclosure, rather than detailing the drawings overload, which will be readily apparent to those skilled in the art who are familiar with the present description.

DETAILED DESCRIPTION:

In order to promote an understanding of the invention, reference will now be made to the embodiment shown in the drawings and the same will be described in specific words. It is to be understood, however, that this is not intended to limit the scope of the invention, but such changes and further modifications to the system illustrated and such further applications of the principles of the invention set forth therein are contemplated by one skilled in the art invention would normally come up with.

Those skilled in the art will understand that the foregoing general description and the following detailed description are exemplary and illustrative of the invention and are not intended to limit the same.

When reference is made to “an aspect,” “another aspect,” or the like in this description, it means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment the present invention is included. Therefore, the expressions “in one embodiment,” “in another embodiment,” and similar expressions in this specification may or may not all refer to the same embodiment.

The terms "comprising", "including" or other variations thereof are intended to cover non-exclusive inclusion, so that a method or method comprising a list of steps not only includes those steps, but may also include other steps that are not are expressly listed or belong to such a process or method. Likewise, one or more devices or subsystems or elements or structures or components introduced with "comprises...a" do not exclude, without further limitation, the existence of other devices or other subsystems or other elements or other structures or other components or additional devices or additional subsystems or additional elements or additional structures or additional components.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by one skilled in the art to which this invention pertains. The system, methods and examples provided herein are for illustrative purposes only and are not intended to be limiting.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Composition for controlling the compressive strength of geopolymer concrete based on fly ash and slag: binder index, the composition comprising: a geopolymer concrete such as fly ash and ground granulated blast furnace slag (GGBS); an alkaline activator solution; and a variety of aggregates.

In one embodiment, the aggregate consists of coarse and fine aggregates.

In one embodiment, the molarity of the alkaline activator ranges from 6M to 12M.

1 shows a block diagram of a system (100) for controlling the compressive strength of geopolymer concrete based on fly ash and slag: binder index, the system (100) comprising: a collection unit (102), a cup (104) and a reactor (106).

The collection unit (102) collects at least one binder for geopolymer concrete rich in silica and alumina. Beaker (104) for preparing an alkaline activator solution by mixing sodium hydroxide (NaOH) and sodium silicate (Na ₂ SiO ₃ ); and a reactor (106) connected to the beaker (104) and the collection unit (102) for performing geopolymerization of the binder and the produced alkaline activator solution to form optimized complex polymers.

In one embodiment, the binder consists of aluminosilicates, alkaline activated solution hydroxides and water.

In one embodiment, the ratio of alkaline activator to binder is in the range of 0.64-0.67.

In one embodiment, the reactor (106) includes a stirrer (108) for mixing the binder and the alkaline solution, the stirrer (108) being either a magnetic stirrer or a mechanical stirrer.

wobei M = Molarität von NaOH; A = Gehalt an alkalischem Aktivator (sowohl NaOH als auch Na₂ SiO₃ zusammen); G = GGBS-Gehalt; F = Flugaschegehalt.In one embodiment, the strength of GPC increases with molarity, alkali to binder ratio and GGBS to FA ratio at _{constant Na2SiO3} /NaOH ratio. It will assumed that the strength of GPC is proportional to the molarity of the alkaline solution, the ratio of alkali to binder (GGBS + FA), and the ratio of GGBS to FA. The determined parameters are combined into a single parameter, called “binder index (Bi),” to which the strength of GPC can be related. The proposed binder index (Bi) is therefore: $$b_i=\frac{MA}{G+F}\left[\frac{G}{F}\right]$$

where M = molarity of NaOH; A = alkaline activator content (both NaOH and Na ₂ SiO ₃ together); G = GGBS content; F = fly ash content.

show the variation of compressive strength of GPC (fgpc) with the proposed binder index (Bi).

N und L sind die Konstanten. Die Gleichung wird für die anfängliche Abschätzung der Festigkeit bei der Mischungsentwicklung von GPC verwendet.The compressive strength of GPC increases with increasing binder index. The observed variation of compressive strength of GPC (f _gpc ) with binder index (Bi) shows that the proposed form of binder index, which combines the effects of molarity of NaOH, alkali to binder ratio and GGBS to fly ash ratio, as only parameter can be considered that influences the compressive strength of GPC mixtures. The variation of the compressive strength of GPC (f _gpc ) with the binder index (Bi) can be represented by a simple power equation of the following form. $$f_{Gpc}=N{\left[bi\right]}^L$$

N and L are the constants. The equation is used for initial strength estimation in GPC mix development.

In one embodiment, the effect of molarity (M)/concentration of sodium hydroxide (NaOH) solution on the compressive strength of geopolymer concrete is analyzed. It is found that as the molarity increases, the compressive strength of geopolymer concrete also increases. For a given ratio of alkaline activator to binder (i.e. A/B = 0.64), with an increase in the ratio of GGBS to fly ash from 0.25 to 2.3, the compressive strength of the geopolymer concrete increased by 175%, 156%, 139% and 107% at a molarity of the NaOH solution of 6M, 8M, 10M and 12M, respectively.

The effect of molarity of NaOH solution for the different ratios of GGBS to fly ash on the flexural strength of geopolymer concrete is analyzed. It is found that as the molarity increases, the flexural strength of the geopolymer concrete also increases. However, the increase in strength is not proportional to the increase in molarity. For a given ratio of alkaline activator to binder (i.e., A/B = 0.64), the flexural strength of geopolymer concrete increased by 89.8%, 96.1, with an increase in the ratio of GGBS to fly ash from 0.25 to 2.3 %, 77.6% and 73.6% at molarity of 6M, 8M, 10M and 12M of NaOH solution, respectively.

The effect of alkaline activator to binder ratio (A/B) and molarity of NaOH solution on compressive strength of geopolymer concrete at a certain ratio of GGBS to fly ash is analyzed. The compressive strength of geopolymer concrete increased with an increase in the ratio of alkaline activator to binder. However, the rate of increase in compressive strength was higher at higher GGBS to fly ash ratios. At a certain ratio of GGBS to fly ash (i.e. G/F = 0.67), with an increase in the alkaline activator to binder ratio from 0.25 to 1.50, the compressive strength of the geopolymer concrete increased by 150%, 121%, 94% and 60% at a molarity of 6M, 8M, 10M and 12M of the alkaline activator, respectively. At a constant value of low molarity (6M) and the ratio of GGBS to fly ash (0.67), the ratio of alkaline activator to binder content increases from 0.45 to 0.64 and the compressive strength of geopolymer concrete increases from 125% to 150% . In the case of high molarity (12M) and GGBS to fly ash ratio (0.67), the compressive strength of geopolymer concrete increased from 48% to 60% when the alkaline activator to binder ratio was increased from 0.45 to 0.64 . Therefore, using a stronger alkaline activator to binder content ratio is beneficial for increasing the strength of geopolymer concrete prepared with a low molecular weight NaOH solution. The flexural strength of geopolymer concrete increases with a higher ratio of alkaline activator to binder. However, the rate of increase in flexural strength is more or less uniform when the ratio of alkaline activator to binder (A/B) is increased with the same molarity of the NaOH solution. For a given ratio of GGBS to Fly ash (i.e. G/F = 0.67), the flexural strength of the geopolymer concrete increased by 70%, 69%, 51% and 55% for the molarity of the with an increase in the ratio of alkaline activator solution to binder from 0.25 to 1.50 NaOH solutions of 6M, 8M, 10M and 12M, respectively. In the case of constant low or high molarity (6M or 12M) and at a constant ratio of GGBS to fly ash (0.67), increasing the A/B ratio from 0.45 to 0.64 resulted in a percentage increase in flexural strength of geopolymer concrete, which was between 51% and 70%.

The effect of the ratio of GGBS to fly ash and molarity of alkaline activator on the compressive strength of geopolymer concrete at a certain ratio of alkaline activator solution to binder content is analyzed. The compressive strength of the geopolymer concrete increased with an increase in the ratio of GGBS to fly ash. However, the rate of increase in compressive strength was higher when the ratio of GGBS to fly ash was less than 1.0, as indicated by a larger increase in compressive strength with a change in molarity.

The effect of GGBS to fly ash ratio and alkaline activator molarity on the flexural strength of geopolymer concrete at a certain alkaline activator to binder ratio is analyzed. The flexural strength of the geopolymer concrete increased with an increase in the ratio of GGBS to fly ash. However, the rate of increase in flexural strength compared to the compressive strength of the geopolymer concrete was lower for all GGBS-fly ash ratios.

The “Binder Index (Bi)” includes the effects of the ratio of GGBS to fly ash (G/F), the ratio of alkaline activator solution to binder content (A/B) and the molarity of NaOH solution (M), which affect the strength of geopolymer concrete based on GGBS and fly ash. The compressive strength of geopolymer concrete increased with the increase of the binder index. However, the increase in strength was not proportional to the increase in binder index. There is a nonlinear variation between the binder index and the compressive strength of geopolymer concrete. The relationship between the compressive strength of geopolymer concrete based on fly ash and GGBS after 28 days and the binder index (Bi) is calculated as follows $${}_{\text{fgpc}}=17.70[{}^{bi]0.41}$$

Where f _gpc is the compressive strength of geopolymer concrete after 28 days and Bi is the binder index. The flexural strength of geopolymer concrete increases with increasing binder index and is on a similar line as the compressive strength of geopolymer concrete. The relationship between the flexural strength of the geopolymer concrete based on fly ash and GGBS after 28 days and the binder index (Bi) is given as follows: $${\text{f}}_{\text{flexural}}=1.77{\left[bi\right]}^{0.28}$$

Where f _flexural is the flexural strength of geopolymer concrete after 28 days and Bi is the binder index. The variation of strengths with binder index corresponds to the proposed equation for geopolymer blends and follows the nonlinear power equation.

The compressive strength at a binder index of 5.40 is considered as the reference strength in the phenomenological model. The compressive strength corresponding to each binder index value is calculated using the proposed phenomenological model and listed in Table 1 for comparison with the experimental values. Binder Index (Bi) Experimental compressive strength (N/mm ² ) ( _{fgpc e} ) Predicted compressive strength * (N/mm ² ) ( _{fgpc p} ) 0.96 16.62 18.01 1.65 18.14 20.62 2.57 24.97 April 23rd 3.84 37.82 25.47 5.76 41.69 28.19 8.95 45.67 31.47 1.28 19.27 7:35 p.m 2.20 23.45 22.16 3.43 30.17 24.76 5.12 38.53 27.37 7.68 42.71 30.29 11.93 49.34 29.97 1.60 22.53 20.46 2.75 25.99 23.43 4.29 37.41 26.18 6.40 39.55 28.94 9.60 43.83 32.03 14.91 53.92 30.65 1.92 27.93 21.42 3.30 30.07 24.53 5.15 39.65 27.40 7.68 41.08 30.29 11.52 44.75 29.87 17.89 58.00 31.21 0.83 13.33 17.34 2.21 8:00 pm 22.19

There is a close agreement between the experimental and predicted values, highlighting the applicability of the phenomenological model with a correlation of 0.911. Binder Index (Bi) Experimental compressive strength (N/mm ² ) ( _{fgpc e} ) Predicted compressive strength * (N/mm ² ) ( _{fgpc p} ) 4.95 33.33 27.14 1.10 10/19 18.63 2.95 28.88 23.84 6.60 35.55 29.16 1.38 21.33 19.70 3.69 33.33 25.21 8.25 37.33 30.84 1.65 25.77 20.62 4.42 34.22 26.38 9.90 40.44 32.27 0.68 12.62 16.49 1.81 November 17th 21.10 4.05 28.44 25.81 0.90 02/19 17.72 2.41 25.77 22.67 5.40 28.88 27.74 1.13 08/20 18.74 3.02 28.44 23.98 6.75 30.53 29.33 1.35 24.44 19.61 3.62 31.11 09/25 8.10 36.13 30.69 The drawings and the preceding description provide examples of embodiments. The person skilled in the art will understand that one or more of the elements described can certainly be combined into a single functional element. Alternatively, certain elements can be divided into several functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of the processes described herein may be changed and is not limited to the manner described herein. Additionally, the actions of a flowchart do not have to be performed in the order shown; Not all actions necessarily have to be carried out. The actions that are not dependent on other actions can also be carried out in parallel with the other actions. The scope of the embodiments is in no way limited by these specific examples. Numerous variations are possible, regardless of whether they are explicitly listed in the description or not, such as: B. Differences in structure, dimensions and use of materials. The scope of the embodiments is at least as broad as specified in the following claims.

Advantages, other benefits, and solutions to problems have been described above with respect to particular embodiments. However, the advantages, benefits, solutions and components that may cause an advantage, benefit or solution to occur or become more pronounced are not to be construed as a critical, necessary or essential feature or component of any or all of the claims.

Claims (7)

Composition for controlling the compressive strength of fly ash and slag through a geopolymer concrete: binder index, the composition comprising: a geopolymer concrete such as fly ash and ground granulated blast furnace slag (GGBS); an alkaline activator solution; and a variety of aggregates. Composition according to Claim 1 , where the aggregate consists of coarse and fine aggregates. Composition according to Claim 1 , where the molarity of the alkaline activator is in the range of 6M to 12M. A system (100) for controlling the compressive strength of fly ash and slag through a geopolymer concrete: binder index, the system (100) comprising: a collection unit (102) for collecting at least one silica- and alumina-rich binder for geopolymer concrete; a beaker (104) for preparing an alkaline activator solution by mixing sodium hydroxide (NaOH) and sodium silicate (Na ₂ SiO ₃ ); and a reactor (106) connected to the beaker (104) and the collection unit (102) for performing geopolymerization of the binder and the produced alkaline activator solution to form optimized complex polymers. System after Claim 4 , where the binder consists of aluminosilicates, alkaline activated solution hydroxides and water. System after Claim 4 , wherein the reactor (106) comprises a stirrer (108) for mixing the binder and the alkaline solution, the stirrer (108) being either a magnetic stirrer or a mechanical stirrer. System after Claim 4 , where the ratio of alkaline activator to binder is in the range of 0.64 to 0.67.

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