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GEOPOLYMER BINDERS: REVIEW
ZHAKANOV ALIBEK NURZHANOVICH
PhD student, Faculty of «Engineering and Construction» L.N. Gumilyov Eurasian National University
Scientific adviser - ARUOVA L.B., Doctor of Technical Sciences, Professor
Astana, Kazakhstan
Annotation: In this work, the materials and structural characteristics of geopolymer concrete are considered in order to identify existing gaps in research and determine directions for their further development. The analysis confirmed that geopolymer concrete can become a worthy alternative to traditional materials, due to its excellent mechanical properties, greater strength and improved structural characteristics. applications require additional research aimed at developing design standards, as well as extensive testing of structural elements to confirm their viability in real conditions. This article reviews articles by several authors based on fillers and activators from industry by-products, a review of the articles shows that the use of fillers and aluminosilicate gels shows an improvement in mechanical properties, reduce environmental impact andprovide economic benefits. Further research is needed to optimize the use of fillers from the processing of industrial waste concrete based on geopolymer binders.
In this context, geopolymer concrete has attracted significant attention from scientists and specialists due to its ability to use by-products as a substitute for cement, which reduces greenhouse gas emissions during its production. In addition, this material exhibits improved mechanical properties and increased durability compared to traditional concrete.
Keywords: fillers from industrial waste processing, geopolymer binders, workability, strength, durability, economic efficiency.
Introduction:
In the construction industry, the production of Portland cement mainly causes the emission of pollutants, which leads to environmental pollution. It is widely known that the production of Portland cement consumes a significant amount of energy and at the same time contributes a large amount of CO2 to the atmosphere. which prompts the search for more environmentally friendly materials [1]. One possible alternative is the use of an alkali-activated binder using industrial by-products containing silicate materials.
Geopolymer is an inorganic polymer binder first developed by French scientist Joseph Davidowitz in the 1970s.
Geopolymer concrete is a special type of concrete used for the construction of all civil and structural construction projects. It plays an important role in construction. The combination of various inorganic molecules makes it possible to obtain this type of concrete. It is a good alternative and one of the good innovative materials compared to standard conventional concrete. It may be known for reducing CO2 emissions, which is why it can also be called green concrete.
History of Self-Compacting Concrete:
According to Davidowitz (2013), who invented and pioneered the word "geopolymers", they belong to a family of inorganic polymers similar to naturally occurring zeolite materials (Bachhav & Dubey, 2016), which are formed by the chemical reaction of aluminum oxides and silicates (Si2O5, AhO3) with polymeric polysilicates to form polymeric bonds of silicate oxide aluminate (Si-O-Al).
The activation of aluminium oxide silicate materials such as fly ash, blast furnace slag and metakaolin using alkaline solutions to produce binders without Portland cement is an important step towards increasing the beneficial use of industrial waste and reducing the negative impact of cement production.
Today, geopolymer is widely used in a variety of construction projects, including high-rise buildings, bridges, and tunnels. Its advantages over traditional concrete include improved machinability, higher strength, and reduced labor costs. The development of geopolymer has revolutionized the construction of concrete structures, and it is likely to remain one of the main areas of research in the concrete industry in the coming years. Overview of the research:
Ganapati Naidu et al. (2012) investigated the strength properties of geopolymer concrete using the replacement of low-calcium fly ash with slag in 5 different percent. Sodium silicate (103 kg/m3) and sodium hydroxide 8 molar (41 kg/m3) solutions were used as alkalis in all 5 different mixtures M1, M2, up to M5. The maximum compressive strength of 57 MPa was achieved in 28 days. The same mixture (Mix no5) appears at a pressure of 43.56 MPa after exposure to 500°C for 2 hours. Higher concentrations of GGBS result in higher compressive strength of geopolymer concrete. The mixing of G.G.B.S was tested up to 28.57%, after which direct setting was observed. There is no need to expose geopolymer concrete to a higher temperature to achieve maximum strength if a minimum of 9% fly ash is replaced by GGBS. 90% compressive strength was achieved in 14 days. [2]
Ravindra Singh Shekhawat et al. (2013) the purpose of his thesis was to investigate the possibilities of using LD slag in geopolymer concrete and trying to explore the potential of steel slag as one of the raw materials for the production of M20 grade geopolymer concrete, and steel slag has a lower reactivity in the geopolymer system and has been used in combination with fly ash and granular blast furnace slag. The behavior of geopolymerization has been studied using isothermal heat-conducting calorimeter. The developed geopolymer concrete showed compressive strength similar to M20 concrete. The expected strength is 25 MPa, but not the expected strength. The maximum strength achieved after 28 days is 24.15 N/mm2 and the minimum is 13.45 N/mm2. One of the possible reasons for this decrease in strength is the percentage of binder in the composition.[3] B. Rajini et al. (2014) the aim of his thesis was to study GGBS and fly ash as different levels of substitution (FA0-GGBS100, FA25-GGBS75, FA50-GGBS50; FA75-GGBS25, FA100, GGBS0). The compressive and splitting strength of geopolymer concrete of 54.29 N/mm2 and 2.46 N/mm2 respectively are the maximum for FA0-GGBS100 regardless of the curing period. The rate of increase in compressive strength and tensile strength when splitting geopolymer concrete is very fast with a 7-day curing period and decreases with age.[4]
A. Rajerajeswari et al. (2014) investigated the possibility of silica vapor-based geopolymer concrete to determine its compressive strength, taking into account parameters such as the effect of the Na2SiO3/NaOH ratio, the effect of the AL/SF ratio, and the effect of the age of the concrete. As a result of the experimental study, it was found that out of three different Na2Sio3 ratios, three different AL/SF ratios, four different ages of silica vapor-based geopolymer concrete AL/SF=0.25 and Na2SiO3/NaOH=0.5 gave a better increase in compressive strength. When considering the ratio AL/SF = 0.25, there is an increase in strength of 73% within 3 to 7 days, by 38% within 7 to 28 days, by 15% within 28-56 days for all Na2SiO3/NaOH ratios, similarly, when considering Na2SiO3/NaOH=0.5, there is an increase in strength by 84% within 3 to 7, 38% for 7-28, 15% for 28-56 days for all AL/SF ratios and 60% silica vapor replacement yielded better compressive strength compared to normal concrete under normal curing.[5]
T.V. Srinivas Murthy et al. (2014) studied the production of geopolymer concrete, Portland cement is completely replaced by GGBS (ground granular blast furnace slag), and alkaline liquids are used to bind materials. Curing is carried out in an oven cured at a temperature of 65°C. For this study, M50 concrete mixture was used for experimental work, the test results of which show that the use of GGBS based on geopolymer concrete It increases the compressive strength, tensile strength and flexural strength by 13.82%, 18.23%, 30.19% respectively compared to ordinary concrete.[6]
Extensive research has been carried out on the use of fillers from industrial waste processing in the production of geopolymer concrete. The researchers studied the effects of various industrial waste-based fillers (fly ash, slag) on the properties of geopolymer concrete, including workability, strength, and durability. Studies have shown that the addition of fillers based on industrial waste
processing (fly ash, slag) can significantly improve the mechanical properties of geopolymer concrete, such as compressive strength, flexural strength, and modulus of elasticity. In addition, the use of fillers (fly ash, slag) can eliminate the use of cement required for the production of geopolymer concrete, which can reduce CO2 from concrete production.
In this review article, several articles on the topic "Geopolymer binders based on industrial waste" were considered. These articles review the latest innovations in geopolymer concrete containing industrial waste. The latest achievements in the field of filler application and their impact on the quality of geopolymer concrete concrete are also considered.
Researchers Rao. Anuradha et al., who are students of Civil Engineering at the Faculty of Civil Engineering, Coimbatore, India, in their article "Modified Guidelines for the Calculation of Geopolymer Concrete Mixtures Using the Indian Standard"[7] This experimental study aims to determine the ratio of components for different grades of geopolymer concrete by trial and error. a new design methodology was formulated, which was in accordance with the Indian standard (IS 10262-2009). The applicability of the existing mix project was studied using geopolymer concrete. In this study, two types of systems were considered, using 100% ASTM Class F Grade Ash Cement Replacement and 100% Sand Replacement with M-Sand. Based on the test results, it was analyzed that the Indian standard mixture design itself with some modifications can be used for geopolymer concrete.
An article authored by Kinga Korniejenko and Michal Lach on the topic "Feasibility Study of a Controlled Low-Strength Material Using Co-Incineration of Fly Ash from a Bubbling Fluidized Bed Boiler" [8] presents the results of a study on the reuse of co-firing resources of fly ash co-incineration from a bubbling boiling kettle to produce a controlled low-strength material (CLSM). First, they conducted Pozzolanic activity test to confirm whether fly ash can be used as a raw material for the manufacture of binders. We then produce samples of fly ash co-roasting binders using different weight percentages (5%, 10%, 15% and 20% each) and use them to perform a variety of tests, including initial setup time, drawdown, compression, X-ray diffraction experiments and mercury microstructure on the SEM.
The result shows that the strength activity index (SAI) of co-incineration fly ash exceeds 75 percent of materials that can be used as raw materials and meet ASTM C311 standard. The above results indicate that co-incineration of fly ash from a fluidized bed bubble boiler can be used as a substitute for binders in controlled low-strength materials. The best percentage of substitutions is 15 percent.
Pozzolanic Activity Index Test
Table LPozzolanjc strength index test results. (data taken from [8])
Substitution Ratio Compressive strength (kgf/cm2) RSFC (%)
7 days 28 days 7 days 28 days
0% 31.7 39.3 100.0 100.0
10% 32.5 42.3 101.5 107.6
20% 29.8 36.7 94.0 93.4
According to their research, it was found that the resulting Pozzolanic Strength Activity Index (SAI) value for assessing whether co-firing ash (in a bubble fluidized bed boiler) has BFBB cementitious capacity, and BFBB co-firing ash replaces 10% and 20% of cement material in (Controlled Low-Strength Materials) CLSM for cement slurry mixing and preparation test samples, and the compression test was carried out when the age of the tested body reached 7 days and 28 days.
In accordance with the requirements of the ASTM C311 test specification, the SAI value of the test group should be greater than 75% of the strength of the control group. The test results show that when the test body is 7 days old, 10% and 20% of the cement material is replaced by burnt fly ash. SAI is 101.5% and 94.0%, respectively; When the test samples reach 28 days of age, co-incineration fly ash replaces 10% and 20% of the cement material, and the SAI values are 107.6% and 93.4%,
respectively, as shown in Table 1. The test results confirmed that BFBB co-firing ash has pozzolanic activity and can be used as a binder.
In the article authored by Tang Van Lam et al. from Vietnam "Geopolymer concrete using large-tonnage man-made waste", the main goal of the experiment was to find out how to reduce the consumption of mixing water while maintaining the required workability of a fine-grained concrete mixture by introducing a polycarboxylate superplasticizer into its composition. [9] As a result of the experiment, these authors came to the following conclusion: A composition of geopolymer concrete on an alkaline cementless binder has been developed, which, as a result of heat treatment for six hours at a temperature of 100 °C at the age of 28 days, has a compressive strength of about 60 MPa, which can be used in the hot and humid climate of Vietnam.
In addition, the production of such concrete will contribute to environmental protection by saving natural resources and the possibility of using large-tonnage man-made waste.
The following table 2 shows the general results of the researchers, the chemical composition of geopolymer concrete containing a combination of additives blast furnace slag of the Hoa Phat Metallurgical Plant (Vietnam) with a true density p = 2.67 g/cm3 and a specific surface area of 3600 cm2/g.
Table 2. Chemical composition of blast furnace slag (data taken from [9])
Average chemical composition, % wt.
SiO2 Al2O3 Fe2O3 High SO3 Loss on Ignition
36,38 15,76 0,55 40,12 1,25 5,94
Graph 1. Chemical composition of blast furnace slag (data taken from [9])
Geopolymer concrete based on fly ash with low calcium content has a number of economic advantages over OPC concrete. Fly ash or blast furnace slag is available very cheaply compared to conventional cement. Alkaline mortar constituents are available at some price, but the total production cost of geopolymer concrete is 10 to 30% less than that of conventional cement concrete [10]. According to the previous analysis [11], for M30 concrete, the cost of production is slightly (1.7%)
higher than for M50 concrete, the cost of OPC concrete is 11% higher than for M50 concrete. The use of fly ash reduces the use of Portland cement, so the production of carbon dioxide into the atmosphere is also reduced and hence the monetary benefits of carbon credit trading. Due to properties such as good fire resistance (up to 1000°C), low shrinkage, excellent sulfate resistance, good acid resistance, geopolymer concrete can bring additional economic benefits when used in infrastructure
The article «Environmental and Economic Savings of Using Fly Ash as a Geopolymer» by Katarina Kulkova, Samer Khoury, Martin Straki and Andrea Rosova from the Technical University of Kosice (Slovakia) explores the potential environmental and economic benefits of using fly ash as a raw material for geopolymers. It is published in the Environmental Protection Yearbook (Volume 20, 2018, ISSN 1506-218X) and addresses several important aspects. [13]
Conclusion:
Overall, studies on the use of industrial waste fillers for Geopolymer Concrete have shown promising results in terms of improving the properties of Geopolymer Concrete while reducing the environmental impact. However, further research is needed to optimize the use of these fillers and examine their long-term performance under operating conditions.
These studies have shown that the inclusion of these fillers can improve the workability, compressive strength, flexural strength, tensile strength, durability, thermal conductivity, and other properties of geopolymer concrete. In addition, the use of these fillers can reduce the carbon footprint and cost of geopolymer concrete, making it a more sustainable and cost-effective construction option. Further research is needed to explore the full potential of these fillers and optimize their use in geopolymer concrete. However, the results of the studies reviewed in this article provide a solid basis for continuing the study of geopolymer concrete fillers used in industrial waste processing, with potential benefits for the construction industry and the environment.
[12].
REFERENCES:
1. Malhotra V. M., 2002, Introduction: Sustainable Development and Technology of Concrete, ACI Concrete International, 24(7).
2. Ganapati Naidu. ., A.S.S.N.Prasad, S.Adiseshu, .V.V.Satayanarayana, "Study of the strength properties of geopolymer concrete with the addition of G.G.B.S", International Journal of Engineering Research and Development, eISSN: 2278-067X, pISSN: 2278-800X, Volume 2, Issue 4, pp. 19-28.
3. Ravindra Singh Shekhawat, Ranjit Parsad, Sanjay Kumar, "Mechanical Properties of Geopolymer Concrete Based on Steel Slag," ResearchGate, publication/309742115.
4. B. Rajini, AV Narasimha Rao, "Mechanical properties of fly ash geopolymer concrete and GGBS as starting materials", International Journal of Innovative Research in Science, Engineering and Technology, ISSN: 2319-8753, Volume 3, Issue 9.
5. Rajerajeshwari, G. Dhinakaran, Mohamed Ershad, "Compressive strength of silica vapor-based geopolymer concrete", Asian Journal of Applied Sciences, ISSN: 1996-3343.
6. T.V. Srinivas Murthy, Dr. Ajit Kumar Rai, "Geopolymer Concrete, Green Concrete, Very Prosuminginthe Industry", International Journal of Civil Engineering and Technology, ISSN 0976 - 6308 (print version), ISSN 0976 6316 (online), Volume 5, Issue 7, pp. 113-122.
7. Modified Guidelines for the Design of Geopolymer Concrete Mixtures Using the Indian Standard Rao, Anuradha V. Srividya, R. Venkatasubramania, B.V. Rangana Faculty of Civil Engineering, VLB Janakiammal College of Engineering and Technology, Kokkaduro, Coimbatore - 641 042, Indiab Curtin University of Technology, Perth, Australia Received: 5 January 2011Accepted: 25 April 2011
8. Cheng, A., Korniejenko, K., Lakh, M., Lin, U. T., Chao, S. D., & Xu, H. M. (2023). Feasibility study of a controlled low-strength material using co-firing of fly ash from a bubbling fluidized bed. V Zhusupbekov, A., Sarsembayeva, G., & Kaliakin, A. (Eds.), Smart geotechnics for smart societies (p. XX). Taylor & Francis. https://www.taylorfrancis.com ISBN: 978-1-003-29912-7.
9. UDC 666.97 DOI: 10.22227/2305-5502.2021.2.2 Geopolymer concrete using large-tonnage man-made waste Tang Van Lam1 , Ngo Xuan Hung2 , Woo Kim Dien2 , B.I. Bulgakov2 , S.I. Bazhenova 2 , O.V. Aleksandrova2 1 Hanoi University of Mining and Geology; Hanoi, Vietnam; 2 National Research Moscow State University of Civil Engineering (MGSU); Moscow, Russia.
10. N.A. Lloyd and B.V. Rangan "Geopolymer Concrete with Fly Ash" Second International Conference on Sustainable Construction and Technologies 28 June-30 June 2010.
11. J.Thaarrini & S.Dhivya "Comparative Study of the Cost of Production of Geopolymer and Conventional Concretes" ISSN 2278-3652 Volume 7, Number 2 (2016), pp. 117-124.
12. B. Vijaya Rangan "Geopolymer Concrete for Environmental Protection" Indian Journal of Concrete, April 2014, Volume 88, Issue 4, pp. 41-48, 50-59.
13. Kulkova, K., Khoury, S., Straka, M., & Rosova, A. (2018). Environmental and economic benefits of using fly ash as a geopolymer. Annual Environmental Review, 20, 73-88.
