Статті в журналах з теми "Geopolymer mortars"
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1
Asprogerakas, A., Aristea Koutelia, Glykeria Kakali, and Sotirios Tsivilis. "Durability of Fly Ash Geopolymer Mortars in Corrosive Environments, Compared to that of Cement Mortars." Advances in Science and Technology 92 (October 2014): 84–89. http://dx.doi.org/10.4028/www.scientific.net/ast.92.84.
Повний текст джерелаАнотація:
In the present paper the durability of fly ash geopolymer mortars compared to that of cement mortars is investigated. Geopolymers can improve the ecological image of building materials, especially when their production is based on industrial by-products such as fly ash. Three series of fly ash based geopolymer mortars were prepared using calcareous sand to fly ash ratio (S/FA) varying from 0.5 to 2. In addition, cement mortar specimens were prepared using cement CEM I 42.5 N and CEM II 32.5 N. Durability of geopolymer and cement mortars was evaluated by means of compressive strength development, acid resistance, chloride diffusion and sulfate resistance. It was found that fly ash can be effectively used to produce geopolymer mortars with calcareous sand. Geopolymers exhibit competitive compressive strength compared to that of cement mortars. Geopolymer mortars develop their maximum compressive strength a few days after their casting. Geopolymer and cement mortars exhibit satisfactory resistance to sulphate attack. Cement mortars, generally, show better behaviour (compared to geopolymers) in chloride diffusion. Finally, geopolymers indicate improved performance against acid attack, compared to that of cement mortars.
2
Belmokhtar, Noureddine, Ikram Frar, Mohammed Ammari, and Laïla Ben Allal. "The Behavior of Geopolymer Mortars Based on Industrial Sludge Exposed to Aggressive Mediums." Journal of Solid Waste Technology and Management 48, no. 2 (May 1, 2022): 313–23. http://dx.doi.org/10.5276/jswtm/2022.313.
Повний текст джерелаАнотація:
There is a growing interest in geopolymer materials. One of its advantages is the possibility of reusing a wide range of industrial waste. This paper aims to study the effect of the molar ratio H2O/Na2O(t) on the physical, chemical, and mechanical properties of industrial slurry-based geopolymers mortars and to evaluate the behavior of the synthesized mortar, which has the shortest setting time, in aggressive mediums. Structural changes in geopolymer mortars were monitored by X-ray diffraction (XRD) and Raman spectroscopy. The morphology of the samples was monitored by the Scanning Electron Microscope (SEM). SEM micrographs of geopolymer mortars show an intimate bond between sand grains and geopolymer cement. The compressive strength of geopolymer mortars varies significantly with the molar ratio H2O/Na2O(t). The mass loss of geopolymer mortars immersed in hydrochloric acid and sulfuric acid is more than that immersed in other solutions but lower than that of Portland cement-based mortars immersed in the same solutions.
3
Istuque, D., L. Soriano, M. V. Borrachero, J. Payá, J. L. Akasaki, J. L. P. Melges, and M. M. Tashima. "Evaluation of the long-term compressive strength development of the sewage sludge ash/metakaolin-based geopolymer." Materiales de Construcción 71, no. 343 (July 30, 2021): e254. http://dx.doi.org/10.3989/mc.2021.13220.
Повний текст джерелаАнотація:
This paper aimed to evaluate the long-term compressive strength development of the sewage sludge ash/metakaolin (SSA/MK)-based geopolymer. SSA/MK-based geopolymeric mortars and pastes were produced at 25ºC with different SSA contents (0 - 30 wt.%). Compressive strength tests were run within the 3-720 curing days range. A physicochemical characterisation (X-ray diffraction and scanning electron microscopy) was performed in geopolymeric pastes. All the geopolymeric mortars presented a compressive strength gain with curing time. The mortars with all the SSA evaluated contents (10, 20, 30 wt.%) developed a compressive strength over 40 MPa after 720 curing days at 25ºC. The maximum compressive strength of the mortars with SSA was approximately 61 MPa (10 wt.% of SSA), similarly to the reference mortar (100% MK-based geopolymer). The microstructure analyses showed that the SSA/MK-based geopolymer presented a dense microstructure with N-A-S-H gel formation.
4
Kawalu, Ndapandula, Abdolhossein Naghizadeh, and Jeffrey Mahachi. "The effect of glass waste as an aggregate on the compressive strength and durability of fly ash-based geopolymer mortar." MATEC Web of Conferences 361 (2022): 05007. http://dx.doi.org/10.1051/matecconf/202236105007.
Повний текст джерелаАнотація:
Geopolymers have been introduced to limit the use of ordinary Portland cement (OPC), as its production contributes to the emission of about 7% of the world’s carbon dioxide, which has a negative effect on the environment. The present study aimed to investigate the effect of glass-waste aggregate on the mechanical properties of fly ash-based geopolymer and OPC mortars. In the study, fly ash geopolymer and OPC mortar mixtures were prepared using glass-waste as fine aggregate. In addition, geopolymer and OPC mortars were also prepared using silica sand as control mixes. A blended solution comprising sodium silicate and sodium hydroxide was used as an alkali activator in fly ash geopolymer mixtures. Fresh mixtures were subjected to workability measurements, while 50 mm cubes were made for compressive strength testing. Mortar prisms of 25 x 25 x 285 mm were prepared and subjected to drying shrinkage test. From the results, the use of glass-waste aggregate negatively affected the compressive strength of the mortars, regardless of the binder type. Geopolymer mortars made using glass-waste aggregate gave 55% lower compressive strength than those made using silica sand. However, mixtures made using glass waste aggregate exhibited better performance in drying shrinkage than those made using silica sand.
5
Samadhi, Tjokorde Walmiki, Pambudi Pajar Pratama, and Nurhidayati Muan. "Development of Geopolymer Utilizing Inorganic Waste Materials." Advanced Materials Research 896 (February 2014): 553–56. http://dx.doi.org/10.4028/www.scientific.net/amr.896.553.
Повний текст джерелаАнотація:
Geopolymers, which are produced by the reaction between aluminosilicate solid precursors and concentrated alkali solutions, is an environmentally attractive construction material due to its much smaller carbon footprint compared to ordinary Portland cement (OPC), and its ability to consume a wide range of solid inorganic waste materials. This work describes the synthesis of geopolymers utilizing local aluminosilicate materials and the evaluation of several key engineering properties of the geopolymer product as a construction cement. A simple 22factorial experiment is undertaken to measure the effect of types aluminosilicate solids (metakaolin produced by calcining a Belitung kaolin at 750 °C, and coal fly ash from an East Java baseload powerplant) and alkali activators (NaOH and KOH solutions) on the initial and final setting time of the geopolymer cement mortar. All geopolymer mortar samples exhibit longer setting times compared to OPC mortars. Statistical analysis indicates that KOH produces faster initial setting than NaOH, while fly ash produces faster setting times compared to metakaolin. A 23factorial experiment is conducted subsequently, adding curing temperature (60 and 80 °C) to the experimental factors. The key engineering property measured in the second experiment is the compressive strength of geopolymer mortars. ANOVA treatment of the measured data indicates that all three experimental factors significantly impacts the compressive strength. Consistent with the preceding experiment, the use of fly ash and KOH significantly increases the strength of the geopolymer mortar. Higher curing temperature is also found to increase the strength. The use of metakaolin as geopolymer precursor produces compressive strength approximately 50% than that of the OPC mortar, while fly ash produces a geopolymer mortar strength that is at least as good as OPC.
6
Vasconcelos, Eduardo, Sérgio Fernandes, Barroso de Aguiar, and F. Pacheco-Torgal. "Concrete Retrofitting Using CFRP and Geopolymer Mortars." Materials Science Forum 730-732 (November 2012): 427–32. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.427.
Повний текст джерелаАнотація:
A new development in the repair and strengthening of reinforced concrete systems is the use of carbon fiber reinforced polymers (CFRP) strips bonded to concrete substrate with epoxy resins. It has been reported that epoxy adhesive are extremely sensitive to high temperatures. Some authors conclude that the epoxy temperature should not exceed 70 °C in order to safeguard the adhesiveness of the epoxy and, thus, the integrity and adequate functioning of CFRP. It is noted that even frequently exposure to direct sunlight causes temperatures higher than 70 °C. Since geopolymers are known to possess high stability at high temperature, these materials can be an alternative to epoxy resins. This papers presents results about the use of metakaolin based geopolymers mortars to insure the adhesion between the CFRP and the concrete substrate. Several compositions of geopolymer mortars were executed by varying the percentage of binder, sand/binder ratio and the concentration of sodium hydroxide. It was found that geopolymer mortars demonstrate very promising performances, having obtained a high mechanical resistance and a good adhesion to concrete. On the other hand the adhesion between CFRP and geopolymer mortars proved to be smaller than expected which could be due, to the fact that the composition of the mortar was not optimized or even to the nature of the CFRP.
7
Pareek, Sanjay, Hiroo Kashima, Ippei Maruyama, and Yoshikazu Araki. "Adhesion characteristics of geopolymer mortar to concrete and rebars." MATEC Web of Conferences 258 (2019): 01012. http://dx.doi.org/10.1051/matecconf/201925801012.
Повний текст джерелаАнотація:
In recent years, geopolymers have gained a wide attention as highly ecological-friendly building materials, having a capability to cut down 70% of CO2 emissions in comparison to the ordinary cement concrete. In this study, geopolymer mortars are proposed as repair materials for reinforced concrete structures, due to their superior acid resistance, heat resistance and high strength in comparison to the existing repair materials. The objective of this study is to investigate the adhesion properties of geopolymer mortars to concrete substrates with different surface treatments, steel plates and rebars. As a result, the geopolymer mortars are found to have excellent adhesion properties to dry concrete substrates, steel plates and rebars. Concrete substrates treated with grinder, further enhanced the adhesion properties of geopolymer mortars. On the other hand, poor adhesion of geopolymer mortars to wet concrete substrates was observed due to the presence of water on the interfacial zone, which decreased the alkali concentration of the geopolymer, resulting in lower adhesion strength. In general, geopolymer mortars are found to have suitable adhesion properties to the concrete substrates, steel plates and rebars and can be applied as repair materials for reinforced concrete structures.
8
Schwaab, S., O. K. Ueno, D. Ganasini, M. V. Folgueras, and Sivaldo L. Correia. "Physical Properties, Mechanical Strength and Microstructure of Fired Clay Brick Waste and Metakaolin Geopolymer Mortars." Materials Science Forum 930 (September 2018): 170–75. http://dx.doi.org/10.4028/www.scientific.net/msf.930.170.
Повний текст джерелаАнотація:
This paper presents a study related to the application of geopolymers cements as a binder on production of mortars for construction and building materials. Geopolymeric cements were produced from metakaolin, clay brick waste and activator consisting of potassium hydroxide and potassium silicate. The mixtures were prepared using standard production processes according Brazilian standards. Hardened properties of density, water absorption, 7-day and 28-day compressive strength were evaluated on samples of cured mortars. Selected samples of fractured specimens were subjected to microstructural characterisation via scanning electron microscopy, X-ray diffraction and thermal analysis. The results for the 7-day and 28-day compressive strength of geopolymer mortars showed that these materials have properties as good as those obtained from Portland cement mortars. Microstructural characterization of fractured pieces showed a morphology usually found in the category of geopolymers product structures.
9
Bringas-Rodríguez, V. C., G. P. Rodríguez-Guillén, F. A. Cuzziramos-Gutiérrez, D. L. Mayta-Ponce, and F. A. Huamán-Mamani. "Study of Mechanical Behavior of Geopolymeric Mortars Reinforced with Ichu Fibers." Key Engineering Materials 931 (September 9, 2022): 167–74. http://dx.doi.org/10.4028/p-0570co.
Повний текст джерелаАнотація:
Reinforced geopolymeric mortars were manufactured by mixing mining tailings, fine sand, Ichu fibers (in variable percentages), sodium hydroxide and water. The microstructure of the obtained mortars consisted of a continuous geopolymer binder phase with sand particles and Ichu fibers dispersed within the binder phase. The real density and average porosity of the reinforced mortars was 2.74 g/cm3 and 34%, respectively. It was possible to verify the influence of the addition of Ichu fibers on the mechanical response in uniaxial compression of the studied mortars, due to the poor interface between the geopolymer and the fibers. The mechanical results revealed a systematic reduction of the maximum compressive strength when the volume of Ichu fibers in the mortar mixtures was increased. On the other hand, a higher degree of deformation was evidenced in mortar mixtures containing a greater amount of Ichu fibers, reaching deformation values of up to 5%. The maximum resistance values found were from 2.87 to 20.76 MPa for samples with 8 and 0 vol.% of Ichu fibers added, respectively.
10
Aziz, Mohamad Abdul Zahari, A. Z. Norzeity, I. Johari, and Shah Rizal Kasim. "Effect of Adding Hydrogen Peroxide (H<sub>2</sub>O<sub>2</sub>) and Sodium Dodecyl Sulphate (SDS) to the Properties of Fly Ash (FA)-Based Geopolymer Mortar." Key Engineering Materials 908 (January 28, 2022): 658–63. http://dx.doi.org/10.4028/p-b9umsp.
Повний текст джерелаАнотація:
Geopolymer is an alternative cementitious material produced by rich aluminosilicate mineral materials (Si-Al) combine with an alkaline activator. The objectives of this study are to study the effect of adding hydrogen peroxide (H2O2) and sodium dodecyl sulphate (SDS) as foaming and stabilizing agents, respectively to the fly ash (FA)-based geopolymer mortar properties. The geopolymer mortars were synthesized with a mixture of FA, alkaline activator and SDS with different H2O2 content. The geopolymer mortars were analyzed using compressive strength test, porosity test and Scanning Electron Microscopy (SEM) analysis. Geopolymer mortar with 1 wt% H2O2 content and 0.5 wt% SDS has the lowest compressive strength (8.67 N) compare to the other geopolymer mortar composition. As H2O2 content increase with presence of SDS, the formation of the pores also increased hence resulting in the low compressive strength of geopolymer mortar.
11
Satya, Yudhi Salman Dwi, Edy Saputra, and Monita Olivia. "Performance of Blended Fly Ash (FA) and Palm Oil Fuel Ash (POFA) Geopolymer Mortar in Acidic Peat Environment." Materials Science Forum 841 (January 2016): 83–89. http://dx.doi.org/10.4028/www.scientific.net/msf.841.83.
Повний текст джерелаАнотація:
This paper presents performance of blended geopolymer mortars prepared from fly ash (FA) and palm oil fuel ash (POFA). Both materials are used their Si and Al elements were activated by alkaline solution. The alkaline solution was prepared by mixing sodium silicate and sodium hydroxide. The optimum mix proportion of geopolymer mortar with FA:POFA mass ratio was 90:10. The ratio of sodium silicate solution to sodium hydroxide solution by mass was 2.5:1. The mass ratio of sand to blended ashes was 2.75:1. The mortar specimens were prepared using 5×5×5 cm cube and cured at room temperature (28oC) for 3 days before subsequently heat-cured at 110oC for 24 hours. The specimens were immersed in distilled water and peat water with pH 4-5 for 120 days. The compressive strength change, porosity, and sorptivity tests were taken. In general, the results shows there was a decrease in strength, an increase in porosity and sorptivity of the blended geopolymer mortars. Fourier Transform Infra Red (FTIR) test revealed that interaction of geopolymers mortar with the acidic peat water can also cause replacement of the exchangeable cations (Na, K) in polymers by hidrogen or hydronium ions. Formation of some new zeolitic phases in blended FA-POFA geopolymer mortar exposed to acidic peat water were observed.
12
Mohamed Rashid, Mohamad Rohaidzat, Hazman Seli, Megat Azmi Megat Johari, and Zainal Arifin Ahmad. "Sago Pith Waste Ash as an Addition to Fly Ash-Based Geopolymer Mortar." Materials Science Forum 888 (March 2017): 462–65. http://dx.doi.org/10.4028/www.scientific.net/msf.888.462.
Повний текст джерелаАнотація:
This paper presents the effects of Sago pith waste ash (SPWA) as a replacement material in fly ash (FA) based geopolymer mortar (from 0 to 40%), from the aspect of mineral composition and compressive strength. The geopolymers were prepared and synthesized using a combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as activator whilst SPWA and FA (by percentage) as high silica-alumina resources. The compressive strength of geopolymer mortar utilizing SPWA/FA was investigated together with the quantitative chemical characteristic via X-ray fluorescence (XRF) and the X-ray diffractometer (XRD). It was observed that by substituting SPWA to partially replacing FA in geopolymer mortar affects the compressive strength as well as the chemical compositions of the mortars. SPWA can increase 5% of the compressive strength (at 10 wt% SPWA, GSPWA10) compared to the FA geopolymer based sample (control). Furthermore, the increment in the percentages of SPWA increased the silica/alumina (SiO2/Al2O3) ratio and that resulted in reduction of compressive strength for other geopolymer mortar samples.
13
Hattaf, Rabii, Abdelilah Aboulayt, Azzedine Samdi, Nouha Lahlou, Mohamed Ouazzani Touhami, Moussa Gomina, and Redouane Moussa. "Reusing Geopolymer Waste from Matrices Based on Metakaolin or Fly Ash for the Manufacture of New Binder Geopolymeric Matrices." Sustainability 13, no. 14 (July 20, 2021): 8070. http://dx.doi.org/10.3390/su13148070.
Повний текст джерелаАнотація:
The increasing use of geopolymer materials in the construction and civil engineering sectors generates a large amount of non-biodegradable waste that will end up in landfills. It is therefore necessary to anticipate solutions for the proper management of this waste. In this work, new geopolymer materials were fabricated by partially replacing the reactive raw minerals (fly ash, FA, or metakaolin, MK) with used geopolymers (fully fly ash-based, FAref, or metakaolin-based, MKref), in order to develop a strategy to reuse geopolymer waste. Their workability and setting behavior were studied in the fresh state, and the geopolymerization process was investigated by calorimetry and by electrochemistry. Mechanical properties and the ability for coating mineral aggregates were assessed, and the resulting adhesion properties were analyzed using matrix/sand mortars. It appears that the new geopolymer materials as well as the mortars are endowed with good performances. The compressive strengths are above 50 MPa and therefore meet the requirements of different construction materials. This demonstrates the recyclability of geopolymer materials. Moreover, an analysis of the influence of the substitution of recycled geopolymers on the setting and on the mechanical performances of mortars makes it possible to propose a binder-recycled geopolymer interaction model for the formation of new binding matrices.
14
Sitarz, Mateusz, Maciej Urban, and Izabela Hager. "Rheology and Mechanical Properties of Fly Ash-Based Geopolymer Mortars with Ground Granulated Blast Furnace Slag Addition." Energies 13, no. 10 (May 21, 2020): 2639. http://dx.doi.org/10.3390/en13102639.
Повний текст джерелаАнотація:
Geopolymers are less energy-demanding alternatives to Portland cement binders. The subject of geopolymer rheology has not yet been fully explored, and the available literature is limited to a narrow range of material compositions. This paper presents the rheological and mechanical response of fly-ash based geopolymer mortars. Investigations were made of the effect of different levels of ground granulated blast furnace slag (GGBFS) addition levels on the rheological properties of fresh geopolymers as well as their mechanical performances at 2, 14 and 28 days. The aim of the study was to obtain flow curves and to establish the correlation between shear stress and shear rate. The results have shown that geopolymer mortar is a pseudoplastic liquid presenting shear thinning behavior, moreover, with the increase of GGBFS content, higher material strengths were obtained and the total porosity was reduced.
15
Abdollahnejad, Z., F. Pacheco-Torgal, J. B. Aguiar, and C. Jesus. "Durability Performance of Fly Ash Based One-Part Geopolymer Mortars." Key Engineering Materials 634 (December 2014): 113–20. http://dx.doi.org/10.4028/www.scientific.net/kem.634.113.
Повний текст джерелаАнотація:
Environmental concerns regarding the high CO2 emissions related to the production of ordinary Portland cement (OPC) led to research efforts on the development of eco-efficient alternative binders. Geopolymers constitute promising inorganic binders alternative to OPC which are based on aluminosilicates by-products and alkali activators. The geopolymerization technology of aluminosilicates is a complex chemical process evolving dissolution of raw materials, transportation, orientation and polycondensation of the reaction products. Classical two part geopolymers could become more eco-efficient with a lower CO2 footprint if sodium silicate usage is avoided. Besides current geopolymeric mixes can suffer from efflorescence originated by the fact that alkaline or soluble silicates that are added during processing cannot be totally consumed during geopolymerisation. Therefore, new and improved geopolymer mixes are needed. One-part geopolymers (sodium silicate free) were first proposed in 2007. However, very few papers were published on these materials. This paper presents experimental results on the durability performance of one-part geopolymers concerning water absorption, penetration of chloride, carbonation resistance and resistance to acid attack. Hydration products results assessed by FTIR spectra are also presented.
16
Nikolov, Aleksandar, Borislav Barbov, and Elena Tacheva. "Geopolymer mortars based on natural zeolite." Review of the Bulgarian Geological Society 82, no. 3 (December 2021): 25–27. http://dx.doi.org/10.52215/rev.bgs.2021.82.3.25.
Повний текст джерелаАнотація:
Geopolymers based on Bulgarian natural zeolite (clinoptilolite) were synthesized using alkaline activators in order to prepare plaster/render mortar. The influence of the alkali concentrations of the activator solution was examined in regard to tensile strength and adhesion to concrete. Microstructure of the obtained geopolymer pastes was analysed by XRD, FTIR, SEM. The results showed adhesive strength to concrete up to 3.6 MPa and tensile strength up to 5.44 MPa. The present study shows a promising potential of the geopolymers as coating material for concrete.
17
Liu, Jie, and Chun Lv. "Properties of 3D-Printed Polymer Fiber-Reinforced Mortars: A Review." Polymers 14, no. 7 (March 24, 2022): 1315. http://dx.doi.org/10.3390/polym14071315.
Повний текст джерелаАнотація:
The engineering applications and related research of fiber-reinforced cement and geopolymer mortar composites are becoming more and more extensive. These reinforced fibers include not only traditional steel fibers and carbon fibers, but also synthetic polymer fibers and natural polymer fibers. Polymer fiber has good mechanical properties, good bonding performance with cement and geopolymer mortars, and excellent performance of cracking resistance and reinforcement. In this paper, representative organic synthetic polymer fibers, such as polypropylene, polyethylene and polyvinyl alcohol, are selected to explore their effects on the flow properties, thixotropic properties and printing time interval of fresh 3D-printed cement and geopolymer mortars. At the same time, the influence of mechanical properties, such as the compressive strength, flexural strength and interlaminar bonding strength of 3D-printed cement and geopolymer mortars after hardening, is also analyzed. Finally, the effect of polymer fiber on the anisotropy of 3D-printed mortars is summarized briefly. The existing problems of 3D-printed cement and polymer mortars are summarized, and the development trend of polymer fiber reinforced 3D-printed mortars is prospected.
18
Harmaji, Andrie, and Bambang Sunendar. "Utilization of Fly Ash, Red Mud, and Electric Arc Furnace Dust Slag for Geopolymer." Materials Science Forum 841 (January 2016): 157–61. http://dx.doi.org/10.4028/www.scientific.net/msf.841.157.
Повний текст джерелаАнотація:
Geopolymer is an aluminosilicate material that can be prepared from thermal activation of solid material containing alumina and silica as precursor and alkali activator solution. The precursor is an eco-friendly material and has a potency to replace Portland cement (cementless material). In this work, cementless geopolymer mortar was prepared by mixing fly ash as main precursors, red mud, and electric arc furnace dust slag, followed by addition of activator solution containing sodium hydroxide solution and waterglass. X-ray diffraction and Fourier transform infra-red spectroscopy demonstrated the formation of albite in geopolymer mortars, indicating that geopolymer mortars have been successfully formed. The best compressive strength of mortars was 72.80 MPa achieved by using fly ash and red mud with NaOH 12M under ambient curing.
19
Junior, Jacob, Ashish Kumer Saha, Prabir Kumar Sarker, and Alokesh Pramanik. "Workability and Flexural Properties of Fibre-Reinforced Geopolymer Using Different Mono and Hybrid Fibres." Materials 14, no. 16 (August 8, 2021): 4447. http://dx.doi.org/10.3390/ma14164447.
Повний текст джерелаАнотація:
The effects of mono (single type) and hybrid (mixed types) fibres on the workability, compressive strength, flexural strength, and toughness parameters of fly ash geopolymer mortar were studied. The ratio of sand to geopolymer paste of the mortar was 2.75. It was found that workability of mortar decreased more with the use of PP fibres due to its higher dispersion into individual filaments in geopolymer mortar compared to the bundled ARG and PVA fibres. Compressive strength increased by 14% for using 1% steel with 0.5% PP fibres compared to that of the control mixture, which was 48 MPa. However, 25 to 30% decrease of compressive strength was observed in the mortars using the low-modulus fibres. Generally, flexural strength followed the trend of compressive strength. Deflection hardening behaviours in terms of the ASTM C1609 toughness indices, namely I5, I10 and I20 were exhibited by the mortars using 1% steel mono fibres, 0.5% ARG with 0.5% steel and 1% PVA with 0.5% steel hybrid fibres. The toughness indices and residual strength factors of the mortars using the other mono or hybrid fibres at 1 or 1.5% dosage were relatively low. Therefore, multiple cracking and deflection hardening behaviours could be achieved in fly ash geopolymer mortars of high sand to binder ratio by using steel fibres in mono or hybrid forms with ARG and PVA fibres.
20
Liban, Roble İbrahim, Ülkü Sultan Keskin, and Oğuzhan Öztürk. "Mechanical strength variation of zeolite-fly ash geopolymer mortars with different activator concentrations." Challenge Journal of Concrete Research Letters 12, no. 3 (September 15, 2021): 96. http://dx.doi.org/10.20528/cjcrl.2021.03.003.
Повний текст джерелаАнотація:
Zeolite is of a significance for geopolymers as it is a natural precursor and does not require additional heat treatment for activation. However, aluminosilicates sourced from natural sources require additional handling for the best use of exploitation. In this study, geopolymers were synthesized by binary use of zeolite and fly ash as main binding material and sodium silicate and sodium hydroxide as alkaline activator. The influence of alkaline activator ratios and sodium hydroxide concentrations on the compressive strength and flexural strength of the zeolite-fly ash based geopolymers were studied. In this research, zeolite-fly ash based geopolymer mortars were produced by using 50% of natural zeolite (clinoptilolite) and 50% of C-type fly ash. Four different activator ratios (Na2SiO3/NaOH: 1, 1.5, 2 and 2.5) and two sodium hydroxide molarities (10M and 12M) was utilized to activate zeolite and fly ash in order to determine the effect of these parameters on the mechanical strengths of the produced geopolymer mortars. The results indicated that as the alkaline activator ratio and NH molarity were increased the compressive strength of the zeolite-fly ash based geopolymers also increased. The maximum compressive and flexural strength values obtained after 28 days of curing were 20.1 MPa and 5.3 MPa respectively and corresponds when used activator ratio of 2.5 and sodium hydroxide concentration of 12 molarity. The obtained results indicated that both the alkaline activator ratio and sodium hydroxide concentration affected the compressive and flexural strengths of zeolite-fly ash based geopolymer mortar specimens.
21
El Moustapha, Bouha. "Effect of Metakaolin Addition on The Mechanical Performance and Durability of Granulated Blast Furnace Slag Based Geopolymer Mortar with Micro-Encapsulated Phase Change Materials." Journal of Cement Based Composites 2, no. 1 (January 5, 2021): 23–31. http://dx.doi.org/10.36937/cebacom.2021.001.005.
Повний текст джерелаАнотація:
Incorporating microcapsule phase change materials (MPCM) into geopolymer is one of the most successful solutions for enhancing building thermal comfort and replacing Portland cement-based materials. Although MPCM improves the thermal capacity of the cementitious matrix, whether it's made of cement or geopolymer, it presents a number of disadvantages in terms of mechanical and physical performance. Several researchers have pointed out that this scientific subject remains unresolved. The purpose of this study is to investigate the influence of 10% and 20% metakaolin (MK) inclusions on the mechanical properties and durability of geopolymer-MPCM mortars based on granulated blast furnace slag (GBFS) and to compare them with Portland cement-MPCM based mortars. The results show that the addition of two proportions of metakaolin is able to compensate well for the loss of mechanical strength associated with the addition of MPCM. Thus, up to 20% MPCM, the addition of metakaolin increases compressive strength by approximately 10 MPA. Compared to Portland-MPCM cement mortars, all geopolymer-MPCM mortars show higher compressive strength, better workability and lower porosity. Finally, in terms of durability evaluation, the resistivity measurements reveal that the risk of corrosion of the cement-based mortar on the steel bars is negligible, while the risk of corrosion of the geopolymer-based mortar on the steel bars is low.
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Gencel, Osman, Aliakbar Gholampour, Hayrettin Tokay, and Togay Ozbakkaloglu. "Replacement of Natural Sand with Expanded Vermiculite in Fly Ash-Based Geopolymer Mortars." Applied Sciences 11, no. 4 (February 22, 2021): 1917. http://dx.doi.org/10.3390/app11041917.
Повний текст джерелаАнотація:
Increasing the thermal insulation of building components to reduce the thermal energy loss of buildings has received significant attention. Owing to its porous structure, using expanded vermiculite as an alternative to natural river sand in the development of building materials would result in improvement of the thermal performance of buildings. This study investigates the properties of fly ash (FA)-based geopolymer mortars prepared with expanded vermiculite. The main aim of this study was to produce geopolymer mortar with lower thermal conductivity than conventional mortar for thermal insulation applications in buildings. A total of twelve batches of geopolymers were prepared for evaluating their different properties. The obtained results show that, at a given FA and expanded vermiculite content, the geopolymers prepared with a 10 molar NaOH solution exhibited a higher flowability, water absorption and porosity, as well as a lower dry unit weight, compressive strength, ultrasound pulse velocity and thermal conductivity compared with those prepared with a 15 molar NaOH solution. As is also shown, the geopolymers containing expanded vermiculite (15%) developed a lower flowability (~6%), dry unit weight (~6%), compressive strength (~7%), ultrasound pulse velocity (~6%) and thermal conductivity (~18%), as well as a higher apparent porosity (~6%) and water absorption (~9%) compared with those without expanded vermiculite at a given FA content and NaOH concentration. The findings of this study suggest that incorporating expanded vermiculite in FA-based geopolymer mortar can provide eco-friendly and lightweight building composites with improved sound and thermal insulation properties, contributing toward the reduction of the environmental effects of waste materials and conservation of natural sand.
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Alakara, Erdinç Halis, Özer Sevim, İlhami Demir, and Gazi Günel. "Effect of waste concrete powder on slag-based sustainable geopolymer composite mortars." Challenge Journal of Concrete Research Letters 13, no. 3 (September 29, 2022): 101. http://dx.doi.org/10.20528/cjcrl.2022.03.003.
Повний текст джерелаАнотація:
In this study, the effect of waste concrete powder (WCP) on slag-based geopolymer composite mortars was investigated. Blast furnace slag (BFS) and WCP were used as binders in geopolymer mortars. WCP was substituted into the geopolymer mortar composites at rates of 10%, 20%, 30%, and 40% by weight of slag. Sodium hydroxide (NaOH) solution was used as the alkali activator in the mixtures and the solution activator concentration was chosen as 16 molars (M). After the prepared mortars were cured at 100°C for 24 hours, they were subjected to flexural strength (ffs), compressive strength (fcs), and ultrasonic pulse velocity (UPV) tests. When the obtained results were examined, it was observed that ffs, fcs, and UPV results decreased with the increase in WCP replacement ratio. These decrements were seen clearly, especially after the 20% replacement ratio. However, despite these decrements, the compressive strengths of all groups were found to be above 50 MPa. In addition, it is thought that environmental pollution can be reduced by using WCP in geopolymer composite mortars.
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ÖZKUL, Işılay, Adil GÜLTEKİN, and Kambiz RAMYAR. "Effect of cement and lime on strength and high-temperature resistance of class F and C fly ash-based geopolymer mortars." Journal of Sustainable Construction Materials and Technologies 7, no. 2 (June 28, 2022): 62–69. http://dx.doi.org/10.47481/jscmt.1120446.
Повний текст джерелаАнотація:
Geopolymers have advantages such as good high-temperature, acid and sulfate resistance. Recently, researchers have been working on cement-geopolymer hybrid materials. According to these studies, it is possible to adjust the setting times, to gain strength at ambient temperature and to increase the strength with the use of cement. However, it is known that the structural stability of cement deteriorates at high temperatures, lowering its strength. In this study, the effect of slaked lime and cement inclusion on the strength and high-temperature resistance of Class F and Class C fly ash-based geopolymer mortars was investigated. For this purpose, fly ash was replaced with 10, 20 and 30% cement or 5, 10, 15 and 20% slaked lime. The lime and cement substitutions decreased the compressive strength by 8.9-24.4% in Class F fly ash-based geopolymer mortars. In Class C fly ash, however, the cement addition increased the compressive strength up to 46.6%, but the lime inclusion decreased the strength slightly. There was no significant change in the high-temperature resistance of cement or lime-included Class F fly ash geopolymer mortars exposed to 900°C. However, serious decrease was recorded in the high-temperature resistance of Class C fly ash geopolymers upon partial replacement of the fly ash with either cement or lime.
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Warid Wazien, A. Z., Mohd Mustafa Al Bakri Abdullah, Rafiza Abd Razak, M. A. Z. Mohd Remy Rozainy, Muhammad Faheem Mohd Tahir, and Kamarudin Hussin. "Potential of Geopolymer Mortar as Concrete Repairing Materials." Materials Science Forum 857 (May 2016): 382–87. http://dx.doi.org/10.4028/www.scientific.net/msf.857.382.
Повний текст джерелаАнотація:
Geopolymer mortars which produced by the reaction of fly ash with an alkaline activator and added with sand is going to be developed for use as concrete repair material. Thus, the typical and standard requirement as repair material is reviewed. This paper also discusses the efficiency of geopolymer mortar which is mainly dependent on the excellent bond between the sand and geopolymer binder. Based on the determined formulation of geopolymer mortar, the standard for testing is determined making it potentially becoming as an excellent repair materials.
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Janowska-Renkas, Elżbieta, and Agnieszka Kaliciak. "Properties of geopolymers from conventional fly ash activated at increased temperature with sodium hydroxide containing glass powder obtained from the recycling of waste glass." MATEC Web of Conferences 322 (2020): 01018. http://dx.doi.org/10.1051/matecconf/202032201018.
Повний текст джерелаАнотація:
This paper presents test results of the physical and mechanical properties of geopolymers based on conventional fly ash activated at increased temperature with sodium hydroxide, containing glass powder obtained from the recycling of waste glass. Tests were performed on mortars of a geopolymer binder containing glass powder of various levels of fineness, at quantities ranging from 5 to 95% of the mass of the conventional fly ash. The properties of the geopolymer binder with and without the content of glass powder were determined on the basis of the heat of hydration. The suitability of the application of glass powder in geopolymers was confirmed by results of testing the following parameters using a scanning electron microscope (SEM) and analysis of micro areas (EDS) in geopolymer materials: particle size distribution, density, porosity, X-ray diffraction (XRD). Testing of the compressive strength of the geopolymer mortars was performed after: 1, 7, 14 and 28 days of curing in air-dry conditions. Results of microstructure tests confirm that the glass powder coming from recycled waste glass in presence of the geopolymer binder undergoes reactions of alkaline activation at increased temperature, the products of which are zeolite minerals and sodium silicate gel. On the basis of test results of physical and mechanical properties of the geopolymers, it was proven that the content of glass powder had a beneficial effect on the utility parameters of the obtained material. The aforementioned research confirms the possibility of using waste glass for the production of geopolymer materials applied in the construction industry.
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Dufka, Ámos, Jana Kosíková, and Lenka Mészárosová. "The Use of Geopolymers in Rehabilitation of Reinforced Concrete Structures." Advanced Materials Research 785-786 (September 2013): 224–30. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.224.
Повний текст джерелаАнотація:
The subject of this paper is option analysis of the use of geopolymers as matrixes to repair mortars designated for rehabilitation of reinforced concrete structures. Due to their specific properties, geopolymers show a high potential mainly for special applications. Rehabilitation of reinforced concrete structures exposed to extreme conditions is a field in which it is possible to effectively take advantage of geopolymers ́ exceptional properties. In this particular case, we focus on comparing the behaviour of polymer-cement materials commonly used in the rehabilitation of reinforced concrete structures and the one of geopolymer-based mortars.
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Kaya, Mehmet, and Fuat Köksal. "Influences of high temperature on mechanical properties of fly ash based geopolymer mortars reinforced with PVA fiber." Revista de la construcción 20, no. 2 (August 2021): 393–406. http://dx.doi.org/10.7764/rdlc.20.2.393.
Повний текст джерелаАнотація:
In this study, a geopolymer composite containing PVA fiber was produced to recycle waste fly ash and obtain an eco-friendly binder. Mechanical properties of geopolymer mortars, produced by using F class fly ash which was activated with NaOH (sodium hydroxide), and reinforced by PVA (polyvinyl alcohol) fiber were investigated after high temperature effect. Geopolymer mortar samples produced by mixing with fly ash, sand, water and NaOH were placed in standard molds of 40×40×160 mm3. PVA fibers were used at percentages of 0,5%, 1% and 1,5% by volume in the experiment. Tests were performed on mortars exposed to high temperatures of 200°C, 400°C, 600°C and 800°C for physical and mechanical properties. For the specimens not subjected to high temperatures, an increase in the compressive strength of mortars containing PVA fibers was observed in comparison to mortar without PVA fiber. On the other hand, it was concluded that losses in compressive strength were less for mortar without PVA fiber when compared with the mortars containing PVA fibers. As a result of the modeling, the PVA ratio, which gives the optimum flexural and compressive strength, was determined as 1,47%. As a result of melting of PVA fibers under the effect of high temperature, 83,58% loss of compressive strength was determined in samples containing 1,5% PVA after 800ºC temperature.
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Zhang, Peng, Xu Han, Jinjun Guo, and Hongsen Zhang. "Fractal Characteristics of Geopolymer Mortar Containing Municipal Solid Waste Incineration Fly Ash and Its Correlations to Pore Structure and Strength." Fractal and Fractional 6, no. 11 (November 15, 2022): 676. http://dx.doi.org/10.3390/fractalfract6110676.
Повний текст джерелаАнотація:
Compression and mercury intrusion porosimetry (MIP) tests were conducted to analyze the effect of municipal solid waste incineration fly ash (MSWIFA) content on the mechanical performance and pore structure of geopolymer mortar. The MSWIFA weight contents were 0%, 5%, 15%, 25%, and 35% and the pore diameter distribution, specific surface area, and pore volume were considered to assess the pore structure of the geopolymer mortars. The popular fractal model was used to investigate the fractal features of the geopolymer mortars. Additionally, mathematical models of fractal dimension with pore structural parameters and compressive strength were established. The results showed that the compressive strength of geopolymer mortars decreased while the total pore volume and total specific surface area of mortars increased with the increase in MSWIFA content. As the MSWIFA content increased, the harmless pores (pore diameter < 20 nm) were refined. Specifically, the pores with a diameter of 5–10 nm increased in number but the pores with a diameter of 10–20 nm decreased in number with the increase in MSWIFA content. The pore structure in the mortars showed scale-dependent fractal characteristics. All fractal curves were divided into four segments according to the pore diameter, namely, Region I (<20 nm), Region II (20–50 nm), Region III (50–200 nm), and Region IV (>200 nm). The surface fractal dimension (DS) in Region I and Region IV was between 2 and 3. However, the DS in Region II and Region III was greater than 3, indicating the pores in Region II and Region III were non-physical according to the surface geometry because of the presence of ink bottle pores which distorted the result of the MIP. The complexity of pores in Region I and Region IV was reduced by the addition of MSWIFA. The DS is a comprehensive parameter that well describes the spatial and morphological distribution of pores in geopolymer mortars and exhibited a good correlation with the specific surface area, pore volume, and compressive strength. A mathematical model based on the DS was established to predict the compressive strength of the geopolymer mortar containing MSWIFA.
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Sitarz, Mateusz, João Castro-Gomes, and Izabela Hager. "Strength and Microstructure Characteristics of Blended Fly Ash and Ground Granulated Blast Furnace Slag Geopolymer Mortars with Na and K Silicate Solution." Materials 15, no. 1 (December 28, 2021): 211. http://dx.doi.org/10.3390/ma15010211.
Повний текст джерелаАнотація:
Mineral geopolymer binders can be an attractive and more sustainable alternative to traditional Portland cement materials for special applications. In geopolymer technology the precursor is a source of silicon and aluminium oxides, the second component is an alkaline solution. In the synthesis of geopolymer binders the most commonly used alkaline solution is a mixture of sodium or potassium water glass with sodium or potassium hydroxide or silicate solution with a low molar ratio, which is more convenient and much safer in use. In this paper, we present the influence of sodium or potassium silicate solution on the physical and mechanical properties of fly ash and ground granulated blast furnace slag-based geopolymer mortars. Mercury intrusion porosimetry and microstructural observation allowed for comparing the structure of materials with a different type of alkaline solution. The evolution of compressive and flexural tensile strength with time determined for composites using 10%, 30% and 50% slag contents (referring to fly ash mass) was analysed. The tests were performed after 3, 7, 14 and 28 days. It was observed that, as the amount of slag used increases in the precursor, the strength of the material grows. Mortars with the sodium alkaline solution were characterised by a higher strength at a young age. However, the values of strength 28 days were higher for geopolymers with potassium alkaline solution reaching 75 MPa in compression. Geopolymer mortar microstructure observation indicates a high matrix heterogeneity with numerous microcracks. Matrix defects may be caused by the rapid kinetics of the material binding reaction or shrinkage associated with the drying of the material.
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Pawluczuk, Edyta, Katarzyna Kalinowska-Wichrowska, and Mahfooz Soomro. "Alkali-Activated Mortars with Recycled Fines and Hemp as a Sand." Materials 14, no. 16 (August 15, 2021): 4580. http://dx.doi.org/10.3390/ma14164580.
Повний текст джерелаАнотація:
Nowadays, effective and eco-friendly ways of using waste materials that could replace natural resources (for example, sand) in the production of concrete composites are highly sought. The article presents the results of research on geopolymer composites produced from two types of waste materials—hemp and fine fractions recovered from recycled cement concrete, which were both used as a replacement for standard sand. A total of two research experiments were conducted. In the first experiment, geopolymer mortars were made using the standard sand, which was substituted with recycled fines, from 0% to 30% by weight. In the second study, geopolymers containing organic filler were designed, where the variables were (i) the amount of hemp and the percent of sand by volume (0%, 2.5%, and 5%) and(ii) the amount of hydrated lime and the percent of fly ash (by weight) (0%, 2%, and 4%) that were prepared. In both cases, the basic properties of the prepared composites were determined, including their flexural strength, compressive strength, volume density in a dry and saturated state, and water absorption by weight. Observations of the microstructure of the geopolymers using an electron and optical microscope were also conducted. The test results show that both materials (hemp and recycled fines) and the appropriate selection of the proportions of mortar components and can produce composites with better physical and mechanical properties compared to mortars made of only natural sand. The detailed results show that recycled fines (RF) can be a valuable substitute for natural sand. The presence of 30% recycled fines (by weight) as a replacement for natural sand in the alkali-activated mortar increased its compressive strength by 26% and its flexural strength by 9% compared to control composites (compared to composites made entirely of sand without its alternatives). The good dispersion of both materials in the geopolymer matrix probably contributed to filling of the pores and reducing the water absorption of the composites. The use of hemp as a sand substitute generally caused a decrease in the strength properties of geopolymer mortar, but satisfactory results were achieved with the substitution of 2.5% hemp (by volume) as a replacement for standard sand (40 MPa for compressive strength, and 6.3MPa for flexural strength). Both of these waste materials could be used as a substitute for natural sand and are examples of an eco-friendly and sustainable substitution to save natural, non-renewable resources.
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Ahmed, Hemn Unis, Aso A. Abdalla, Ahmed S. Mohammed, Azad A. Mohammed, and Amir Mosavi. "Statistical Methods for Modeling the Compressive Strength of Geopolymer Mortar." Materials 15, no. 5 (March 2, 2022): 1868. http://dx.doi.org/10.3390/ma15051868.
Повний текст джерелаАнотація:
In recent years, geopolymer has been developed as an alternative to Portland cement (PC) because of the significant carbon dioxide emissions produced by the cement manufacturing industry. A wide range of source binder materials has been used to prepare geopolymers; however, fly ash (FA) is the most used binder material for creating geopolymer concrete due to its low cost, wide availability, and increased potential for geopolymer preparation. In this paper, 247 experimental datasets were obtained from the literature to develop multiscale models to predict fly-ash-based geopolymer mortar compressive strength (CS). In the modeling process, thirteen different input model parameters were considered to estimate the CS of fly-ash-based geopolymer mortar. The collected data contained various mix proportions and different curing ages (1 to 28 days), as well as different curing temperatures. The CS of all types of cementitious composites, including geopolymer mortars, is one of the most important properties; thus, developing a credible model for forecasting CS has become a priority. Therefore, in this study, three different models, namely, linear regression (LR), multinominal logistic regression (MLR), and nonlinear regression (NLR) were developed to predict the CS of geopolymer mortar. The proposed models were then evaluated using different statistical assessments, including the coefficient of determination (R2), root mean squared error (RMSE), scatter index (SI), objective function value (OBJ), and mean absolute error (MAE). It was found that the NLR model performed better than the LR and MLR models. For the NLR model, R2, RMSE, SI, and OBJ were 0.933, 4.294 MPa, 0.138, 4.209, respectively. The SI value of NLR was 44 and 41% lower than the LR and MLR models’ SI values, respectively. From the sensitivity analysis result, the most effective parameters for predicting CS of geopolymer mortar were the SiO2 percentage of the FA and the alkaline liquid-to-binder ratio of the mixture.
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Aboshia, Ali Mohamed Ali, Riza Atiq Rahmat, Muhammad Fauzi Mohd Zain, and Amiruddin Ismail. "Enhancing mortar strengths by ternary geopolymer binder of metakaolin, slag, and palm ash." International Journal of Building Pathology and Adaptation 35, no. 5 (November 13, 2017): 438–55. http://dx.doi.org/10.1108/ijbpa-03-2017-0014.
Повний текст джерелаАнотація:
Purpose The purpose of this paper is to develop an alternative new ternary geopolymer mortar (MKSP) to resolve a traditional mortar problem which exhibits several disadvantages, including poor strengths and surface microcracks and the CO2 air pollution. Design/methodology/approach The MKSP ternary binder was produced using metakaolin (MK), slag (S), and palm oil fuel ash (POFA) activated with an alkaline mixture of sodium silicate (Na2SiO3) and 10 M NaOH in a mass ratio of 2.5. Seven different mix proportions of MK, slag, and POFA were used to fabricate MKSP mortars. The water-to-binder ratio was varied between 0.4 and 0.5. The mortars were heat cured for 2 h at 80°C and then aged in air. Flexural stress and strain, mortars flow and compressive strength were tested. Furthermore, the mortars were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses. Findings The results showed that the sample MKSP6, which contained 40 percent MK, 40 percent slag, and 20 percent POFA, exhibited high compressive strength (52 MPa) without any cracks and flexural strength (6.9 MPa) at 28 days after being cured for 2 h at 80°C; however, the MKSP7 mortar with optimal strength of 55 MPa showed some surface cracks . Further, the results of the XRD, SEM, and FTIR analyses indicated that the MKSP mortars primarily consisted of a crystalline (Si+Al) phase (70 percent) and a smaller amorphous (Si+Ca) phase (30 percent). Research limitations/implications The MKSP ternary geopolymer mix has three limitations as an importance of heat curing for development early strength, POFA content less than 20 percent to gain high normal strength and delaying the sitting time by controlling the slag content or the alkali activator type. Practical implications The use of geopolymer materials binder in a real building is limited and it still under research, Thus, the first model of real applied geopolymer cement in 2008 was the E-Crete model that formed by Zeobond company Australia to take the technology of geopolymer concrete to reality. Zeobond Pty Ltd was founded by Professor Jannie S.J. van (van Deventer et al., 2013), it was used to product precast concrete for the building structure. The second model was PYRAMENT model in 2002 by American cement manufacturer Lone Star Industries which was produced from the development carried out on inorganic alumino-silicate polymers called geopolymer (Palomo et al., 1999). In 2013 the third model was Queensland’s University GCI building with three suspended floors made from structural geopolymer concrete containing slag/fly ash-based geopolymer (Pathak, 2016). In Australia, 2014, the newly completed Brisbane West Wellcamp airport becomes the greenest airport in the world. Cement-free geopolymer concrete was used to save more than 6,600 tons of carbon emissions in the construction of the airport. Therefore, the next century will see cement companies developing alternative binders that are more environmentally friendly from a sustainable development point of view. Originality/value Production of new geopolymer binder of mortar as alternative to traditional cement binder with high early and normal strength from low cost waste materials, less potential of cracking, less energy consumption need and low carbon dioxide emission.
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Chindaprasirt, Prinya, and Kiatsuda Somna. "Improved Acid Rain Resistance of High Calcium Fly Ash-sodium Hydroxide Geopolymer Mortar Cured at Ambient Temperature by Incorporating Rice Husk Ash." Journal of Solid Waste Technology and Management 47, no. 2 (May 1, 2021): 324–31. http://dx.doi.org/10.5276/jswtm/2021.324.
Повний текст джерелаАнотація:
Geopolymer is an aluminosilicate material, synthesized from source materials rich in silica and alumina and alkali solution. This product provides similar strength to Portland cement concrete. Geopolymer exhibits a wide variety of properties and characteristics, including high compressive strength, low shrinkage, acid resistance, fire resistance and low thermal conductivity. In term of acid resistance, acid rain is an important consideration due to global warming. Structures deteriorate as a result of persistence contact with acid rain with of pH less than 5. Thus, this research aims to improve acid resistance of fly ash-NaOH geopolymer mortars by incorporating rice husk ash (RHA). Artificial acid rain solution was prepared by mixing nitric acid and sulfuric acid at the ratio of 70:30 v/v. The geopolymer mortars were immersed in 5% nitric acid, 5% sulfuric acid, and 5% synthetic acid rain solutions for 36 weeks. The evaluations of its resistance to acid solution was investigated with surface corrosion, compressive strength, and microstructure. The results showed that the incorporation of RHA improved the acid rain resistance of geopolymer mortar through pore refinement and increase in strength. The mortar with fly ash to RHA ratio of 90:10 provided the highest compressive strength and good resistance to acid rain.
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Xu, Shengtang, Chaofan Wu, Jinchao Yue, and Zikai Xu. "Shrinkage and Mechanical Properties of Fibre-Reinforced Blast Furnace Slag-Steel Slag-Based Geopolymer." Advances in Civil Engineering 2022 (April 8, 2022): 1–10. http://dx.doi.org/10.1155/2022/8931401.
Повний текст джерелаАнотація:
Geopolymer materials have several obvious advantages such as energy conservation, emission reduction, and waste reuse, so they can become substitutes for cement materials. In this study, geopolymer mortars made from blast furnace slag and steel slag reinforced by basalt fibre and polyvinyl alcohol (PVA) fibre were prepared to explore the effect on their strength and shrinkage properties. Scanning electron microscopy (SEM) was employed to characterize the reaction mechanism of the geopolymer mortars. The results show that both PVA fibre and basalt fibre can improve the mechanical properties of geopolymer mortars during the late curing period. The geopolymer reinforced by basalt fibre manifested a better toughness. A proper content of PVA fibres and basalt fibres can effectively reduce the drying and autogenous shrinkage of geopolymer mortars. The optimal content of basalt fibres and PVA fibres to reduce the drying shrinkage was 0.4%. The SEM results show that the fibres can effectively alleviate the stress concentration and prevent crack propagation.
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Tippayasam, Chayanee, Sarochapat Sutikulsombat, Jamjuree Paramee, Cristina Leonelli, and Duangrudee Chaysuwan. "Development of Geopolymer Mortar from Metakaolin Blended with Agricultural and Industrial Wastes." Key Engineering Materials 766 (April 2018): 305–10. http://dx.doi.org/10.4028/www.scientific.net/kem.766.305.
Повний текст джерелаАнотація:
Geopolymer is a greener alternative cement produced from the reaction of pozzolans and strong alkali solutions. Generally, the cement industry is one of largest producers of CO2that caused global warming. For geopolymer mortar usage, Portland cement is not utilized at all. In this research, geopolymer mortars were prepared by mixing metakaolin, various wastes (fly ash, bagasse ash and rice husk ash) varied as 80:20, 50:50 and 20:80, 15M NaOH, Na2SiO3and sand. The influence of various parameters such as metakaolin to ashes ratios and pozzolans to alkali ratios on engineering properties of metakaolin blended wastes geopolymer mortar were studied. Compressive strength tests were carried out on 25 x 25 x 25 mm3cube geopolymer mortar specimens at 7, 14, 21, 28 and 91 air curing days. Physical and chemical properties were also investigated at the same times. The test results revealed that the highest compressive strength was 20% metakaolin - 80% fly ash geopolymer mortar. When the curing times increases, the compressive strength of geopolymer mortar also increases. The mixing of metakaolin and bagasse ash/rice husk ash presented lower compressive strength but higher water absorption and porosity. For FTIR results, Si-O, Al-O and Si-O-Na+were found. Moreover, the geopolymer mortar could easily plastered on the wall.
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El-Mir, Abdulkader, Hilal El-Hassan, Amr El-Dieb, and Abdelrahman Alsallamin. "Development and Optimization of Geopolymers Made with Desert Dune Sand and Blast Furnace Slag." Sustainability 14, no. 13 (June 27, 2022): 7845. http://dx.doi.org/10.3390/su14137845.
Повний текст джерелаАнотація:
This study assesses the effect of mix design parameters on the fresh and hardened properties, cost, and carbon footprint of geopolymer mortar made with desert dune fines (DDF) and blast furnace slag (BFS). Taguchi method was employed in designing the experiments. Four factors were considered, each having three levels, leading to a total of nine geopolymer mortar mixes. The factors comprised the DDF replacement percentage, alkali-activator solution to binder ratio (AAS/B), sodium silicate-to-sodium hydroxide ratio (SS/SH), and sodium hydroxide (SH) molarity. Ten performance criteria were evaluated, including the flowability, final setting time, hardened density, 1, 7, and 28-day compressive strengths, water absorption, sorptivity, cost, and carbon footprint. ANOVA was carried out to estimate the contribution of each factor towards the response criteria. Further, TOPSIS analysis was utilized to optimize the mixture proportions of DDF-BFS blended geopolymer mortar. Experimental results showed that up to 25% DDF replacement enhanced the density, strength, and durability of the geopolymers with minor impact on the flowability and setting time. Higher replacement percentages had a detrimental impact on the performance but could still be utilized in specific mortar construction applications. The other factors had more limited contributions to the performance, evidenced by the ANOVA. TOPSIS method revealed the optimum mix to be made with DDF replacement of 25%, AAS/B of 0.5, SS/SH of 1.5, and SH molarity of 10 M. Different multivariable regression models were also developed to predict the fresh and hardened properties of the DDF-BFS geopolymer mortars using the mix design parameters.
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Ismail, Salwa, Mohammad Faizal Mohd Razali, Izwan Johari, Zainal Arifin Ahmad, and Shah Rizal Kasim. "Effect of Curing Time and Sintering to the Properties of Geopolymer Mortars." Materials Science Forum 888 (March 2017): 184–87. http://dx.doi.org/10.4028/www.scientific.net/msf.888.184.
Повний текст джерелаАнотація:
In this study, the geopolymer mortars were synthesized with fly ash (FA) and silica powder as aluminosilicate sources and a combination of sodium hydroxide (NaOH) solution, sodium silicate (Na2SiO3) solution and distilled water as alkaline activator. Commercial sago was used as a pore former in the mortars. The percentage of sago used were 10, 20 and 30 wt% of FA. The amount of added water used in each mixture was 5% by weight of FA, NaOH solution and Na2SiO3 solution. The formed geopolymer mortars were cured for 1, 3 and 7 days and sintered at 1000 °C. X-ray fluoresence (XRF) shown that FA contains higher amount of silica (SiO2) and alumina (Al2O3) which is important as aluminosilicate sources. The properties of the geopolymer mortars before and after sintered at 1000 °C have been investigated. The results show that geopolymer mortars with 10% of sago content with curing time of 7 days and sintered at 1000 °C give the highest compressive strength of 13.5 MPa.
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Gurung, Deepa Humbahadur, and Vinay Kumar Jha. "Synthesis of Geopolymer from Coal Fly Ash and its Comparative Study with Fly Ash Based Ordinary Nepalese Cement." Scientific World 13, no. 13 (August 5, 2020): 24–28. http://dx.doi.org/10.3126/sw.v13i13.30502.
Повний текст джерелаАнотація:
The world cement industry is responsible for 5-8 % of the total CO2 emission. Thus, the cement industry has a crucial role in global warming. The search for an alternative green inorganic binder with improved durability led to the discovery of alkali-activated binder termed “geopolymer”. In this study, geopolymer was synthesized from coal fly ash (CFA) with the parameters such as particle size ≤ 53 μm, NaOH concentration 8 M and the mass ratio of CFA/Na2SiO3 was 0.75. For the comparative study with fly ash based cement, the cement mortars were prepared by varying the cements and mass ratio. The highest compressive strength (14.16 MPa) of the cement mortar was however obtained with 1:3 cement sand ratio after 7 days of curing, the ratio of 1:4 was considered for comparison. The cement and geopolymer mixture mortars were also prepared with varying (cement + sand) and (CFA+ NaOH+ Na2SiO3) mass ratio. The maximum compressive strength of 3.84 MPa was obtained for 1:2 mass ratio with 7 days of curing. The maximum compressive strengths of CFA based geopolymer, CFA added cement and cement and geopolymer mixture were 17.06, 21.3 and 11.42 MPa with 90 days of curing respectively.
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Łaźniewska-Piekarczyk, Beata, Monika Czop, and Dominik Smyczek. "The Comparison of the Environmental Impact of Waste Mineral Wool and Mineral in Wool-Based Geopolymer." Materials 15, no. 6 (March 10, 2022): 2050. http://dx.doi.org/10.3390/ma15062050.
Повний текст джерелаАнотація:
Waste generated in fine wool production is homogeneous and without contamination, which increases its chances of reuse. Waste mineral wool from demolition sites belongs to the specific group of waste. However, the storage and collection require implementing restrictive conditions, such as improper storage of mineral wool, which is highly hazardous for the environment. The study focuses on the leachability of selected pollutants (pH, Cl−, SO42−) and heavy metals (Ba, Co, Cr, Cu, Ni, Pb, Zn) from the waste mineral wool. As a solution to the problem of storing mineral wool waste, it was proposed to process it into wool-based geopolymer. The geopolymer, based on mineral wool, was also assessed regarding the leaching of selected impurities. Rock mineral wool is very good for geopolymerisation, but the glass wool needs to be completed with additional components rich in Al2O3. The research involved geopolymer prepared from mineral glass wool with bauxite and Al2O3. So far, glass wool with the mentioned additives has not been tested. An essential aspect of the article is checking the influence of wool-based geopolymer on the environment. To investigate the environmental effects of the wool-based monolith and crushed wool geopolymers were compared. Such research has not been conducted so far. For this purpose, water extracts from fragmented geopolymers were made, and tests were carried out following EN 12457-4. There is no information in the literature on the influence of geopolymer on the environment, which is an essential aspect of its possible use. The research results proved that the geopolymer made on the base of mineral wool meets the environmental requirements, except for the pH value. As mentioned in the article, the geopolymerisation process requires the dissolution of the starting material in a high pH (alkaline) solution. On the other hand, the pH minimum 11.2 value of fresh geopolymer binder is required to start geopolymerisation. Moreover, research results analysed in the literature showed that the optimum NaOH concentration is 8 M. for the highest compressive strength of geopolymer. Therefore, the geopolymer strength decreases with NaO concentration in the NaOH solution. Geopolymers glass wool-based mortars with Al2O3 obtained an average compressive strength of 59, the geopolymer with bauxite achieved about 51 MPa. Thus, Al2O3 is a better additional glass wool-based geopolymer than bauxite. The average compressive strength of rock wool-based geopolymer mortar was about 62 MPa. The average compressive strength of wool-based geopolymer binder was about 20–25 MPa. It was observed that samples of geopolymers grout without aggregate participation are characterised by cracking and deformation.
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Amouri, M. S., and N. M. Fawzi. "The Mechanical Properties of Fly Ash and Slag Geopolymer Mortar with Micro Steel Fibers." Engineering, Technology & Applied Science Research 12, no. 2 (April 9, 2022): 8463–66. http://dx.doi.org/10.48084/etasr.4855.
Повний текст джерелаАнотація:
In this study, experimental mortar combinations with 1% micro steel fibers, were examined to create geopolymer mortars. To test the effect of the fibers on the mortar's resistance, the geopolymer mortar was designed with various proportions of more environmentally friendly materials fly ash and slag. The percentage of fly ash by weight was 50, 60, and 70% of the slag. The best results were obtained when a 50:50 ratio of fly ash and slag were mixed with 1% micro steel fibers. The results showed that the mixtures containing fibers performed better in the considered tests (toughness index, ductility index, and resilience index). In the impact resistance test, the mixture contained 50% fly ash by weight of the slag with a temperature of 240°C and a curing period of 28 days, with and without micro steel fibers. Water absorption test results and void content increased when adding micro steel fibers after 7 and 28 days of curing at 24°C.
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Mizerová, Cecílie, Ivo Kusák, Pavel Rovnaník, and Patrik Bayer. "Conductive Metakaolin Geopolymer with Steel Microfibres." Solid State Phenomena 321 (July 26, 2021): 59–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.321.59.
Повний текст джерелаАнотація:
Research of alkali-activated materials and geopolymers suggests their increased ability to transfer the electric charge thus indicating their suitability for self-sensing and other multifunctional composites. In this paper, the electrical properties of metakaolin geopolymer are enhanced by the incorporated steel microfibres that also improve the mechanical and fractural properties of the composite. Selected electrical properties of metakaolin geopolymer mortars with steel microfibres (up to 30 % of metakaolin wt.) were assessed via impedance spectroscopy analysis and followed by testing their compressive and flexural strength. Mercury intrusion porosimetry and SEM imaging enabled to characterize the binder microstructure and quality of fibre-matrix bonding.
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Kiventerä, Jenni, Juho Yliniemi, Lukasz Golek, Jan Deja, Victor Ferreira, and Mirja Illikainen. "Utilization of sulphidic mine tailings in alkali-activated materials." MATEC Web of Conferences 274 (2019): 01001. http://dx.doi.org/10.1051/matecconf/201927401001.
Повний текст джерелаАнотація:
Disposal of mine tailings is one of the most important environmental issues during the mining lifetime. Especially sulphidic tailings can cause environmental and ecological risks because of their tendency to oxidize in the presence of water or air. Because of small particle size and harmful chemical properties, utilization possibilities of sulphidic mine tailings are limited. The aim of the present study was to develop technologies to utilize sulphidic mine tailings in alkali activated materials. Alkali-activated materials also known as geopolymers are nanosized zeolite type or slightly amorphous materials comparable to traditional Portland cement concrete, which can physically encapsulate or chemically stabilize the hazardous elements such as heavy metals into the 3D structure. Mine tailing based geopolymer aggregates were successfully produced from sulphidic mine tailings with good physical properties. The geopolymer aggregates performed as a concrete aggregate comparable to commercial lightweight aggregates. In addition, geopolymer mortars were prepared from mine tailings. In mortar application, there is a need to add some co-binder such as blast furnace slag in order to achieve high strength for the material. The mine tailing based geopolymer structure has an ability to stabilize a large number of cationic species into the structure while some anionic species were not able to immobilize by alkaline activation.
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Naghizadeh, Abdolhossein, Stephen O. Ekolu, and Fitsum Solomon. "Challenges and Problems of Geopolymer Brick Masonry: A Review." Key Engineering Materials 916 (April 7, 2022): 136–44. http://dx.doi.org/10.4028/p-68r15a.
Повний текст джерелаАнотація:
Geopolymers are known to be environmentally – friendly construction materials that can be used in different applications including concretes and mortars, fire – resistant coating materials, road pavements and masonry units. Despite the economic and environmental – related benefits of utilizing geopolymer products, the production of these materials is also associated with some challenges and difficulties that need to be resolved for the technology to gain recognition and acceptability in the construction industry. In this paper, publications were reviewed to provide some understanding of the problems and challenges of geopolymer brick production. Composition of alkali activator along with curing temperature, are major factors that significantly influence the production cost of geopolymer bricks. Also, incorporation of calcium - rich co - binders into geopolymer mixtures, may lead to reduction in durability resistance of the brick product.
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Olivia, Monita, Chrisfela Wulandari, Iskandar R. Sitompul, Lita Darmayanti, and Zulfikar Djauhari. "Study of Fly Ash (FA) and Palm Oil Fuel Ash (POFA) Geopolymer Mortar Resistance in Acidic Peat Environment." Materials Science Forum 841 (January 2016): 126–32. http://dx.doi.org/10.4028/www.scientific.net/msf.841.126.
Повний текст джерелаАнотація:
Peat is superficial deposit or soil with high organic content. The soil is highly compressible and acidic. The organic acidic water in swampy peat soil consists humic acid that is potentially corrosive to concrete and metal structures. Geopolymer is a material using waste from agro-industry such as fly ash (FA) and palm oil fuel ash (POFA) that is activated with alkaline solution. In this research, the acid resistance of geopolymer mortars from fly ash and palm oil fuel ash was measured by change in compressive strength and porosity. The samples were subjected to distilled water and acidic peat water. The OPC mortars showed a considerable decrease in compressive strength after subjected in peat water for up to 180 days. There was a fluctuated trend of geopolymer FA and a high decrease in compressive strength of geopolymer POFA after subjected to the peat water. The porosity of the geopolymer specimens was higher than the control mortars. However, it was observed that the geopolymer FA is more resistant to the acidic peat water than the geopolymer POFA due to stable aluminosilicate bonding.
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Yodsudjai, Wanchai. "Application of Fly Ash-Based Geopolymer for Structural Member and Repair Materials." Advances in Science and Technology 92 (October 2014): 74–83. http://dx.doi.org/10.4028/www.scientific.net/ast.92.74.
Повний текст джерелаАнотація:
The applications of using fly ash-based geopolymer as a structural member and a repair materials in reinforced concrete structure was conducted. The optimum mix proportion of fly ash-based geopolymer concrete using for structural beam and fly ash-based geopolymer mortar using for repair material were developed. The flexural behavior of fly ash-based geopolymer reinforced concrete and the durability aspect namely the corrosion of steel reinforcement were investigated using the electrical acceleration. For the repair purpose, the fundamental properties; that is, compressive strength, flexural strength, bonding strength between fly ash-based geopolymer mortar and mortar substrate, setting time and chloride penetration were investigated. Also, the durability of conventional reinforced concrete beam repaired by the fly ash-based geopolymer mortar comparing with the comercial repair mortar was investigated. The behavior of the fly ash-based geopolymer reinforced concrete beam was similar to that of the conventional reinforced concrete beam; however, the corrosion of the steel reinforcement of the fly ash-based geopolymer reinforced concrete beam was higher than that of the conventional reinforced concrete beam. The fundamental properties of the fly ash-based geopolymer mortar were not different from that of the commercial repair materials; however, the durability of the reinforced concrete beam repaired by the fly ash-based geopolymer mortars performed a little lower than that of repaired with the commercial repair motar and also the control reinforced concrete with no repair. As a result, even there will be still a need of improvement there was a good tendency for using the fly ash-based geopolymer as the structural member and the repair materials.
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Oleiwi, Safie M., Jinan L. Abbas, Yahyia M. Hameed, Abbas H. Mohammed, and Ali K. Hussein. "Effect of Different Proportions of Fly Ash and GGBFS on the Compressive Strength of Geopolymer Mortar." Annales de Chimie - Science des Matériaux 46, no. 5 (December 14, 2022): 229–33. http://dx.doi.org/10.18280/acsm.460501.
Повний текст джерелаАнотація:
Nowadays, geopolymer plays a significant role in developing eco-friendly materials to avoid the pollution caused by the Portland cement industry. Geopolymer is a developed industrial by-product-based alternative concrete binder. The aim of this study to evaluate the effect of different proportions of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) on the strength properties of geopolymer mortar. In this study, GGBFS was added as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the total binder with NaOH concentrations 12 M and sodium silicate to sodium hydroxide ratio 2.5. The compressive strength was investigated experimentally in this study. The combination of FA and GGBFS were tested in a total of eleven geopolymer mix mortars, and the results show that combining the above constituents at 70℃ improves the compressive strength of geopolymer mortar. The result show that the mixture with 100% GGBFS replacement have maximum compressive strength (78.25 MPa) at 7-days age.
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Luhar, Ismail, and Salmabanu Luhar. "A Comprehensive Review on Fly Ash-Based Geopolymer." Journal of Composites Science 6, no. 8 (July 27, 2022): 219. http://dx.doi.org/10.3390/jcs6080219.
Повний текст джерелаАнотація:
The discovery of an innovative category of inorganic geopolymer composites has generated extensive scientific attention and the kaleidoscopic development of their applications. The escalating concerns over global warming owing to emissions of carbon dioxide (CO2), a primary greenhouse gas, from the ordinary Portland cement industry, may hopefully be mitigated by the development of geopolymer construction composites with a lower carbon footprint. The current manuscript comprehensively reviews the rheological, strength and durability properties of geopolymer composites, along with shedding light on their recent key advancements viz., micro-structures, state-of-the-art applications such as the immobilization of toxic or radioactive wastes, digital geopolymer concrete, 3D-printed fly ash-based geopolymers, hot-pressed and foam geopolymers, etc. They have a crystal-clear role to play in offering a sustainable prospect to the construction industry, as part of the accessible toolkit of building materials—binders, cements, mortars, concretes, etc. Consequently, the present scientometric review manuscript is grist for the mill and aims to contribute as a single key note document assessing exhaustive research findings for establishing the viability of fly ash-based geopolymer composites as the most promising, durable, sustainable, affordable, user and eco-benevolent building materials for the future.
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Ridzuan, A. R. M., A. A. Khairulniza, M. A. Fadzil, and J. Nurliza. "Effect of Alkaline Activators Concentration to the Strength and Morphological Properties of Wastepaper-Based Geopolymer Mortars." Materials Science Forum 803 (August 2014): 88–92. http://dx.doi.org/10.4028/www.scientific.net/msf.803.88.
Повний текст джерелаАнотація:
Waste paper sludge ash (WPSA) is a byproduct that has potential to replace Ordinary Portland Cement (OPC) as a building material. The purpose of this study is to investigate the effect of NaOH concentration on the strength of Waste Paper Sludge Ash (WPSA)-based geopolymer mortar. Initially, the WPSA samples were been analyzed using X-ray Fluorescence (XRF) to determine the chemical composition. From the XRF analysis, the by-product WPSA containing higher amount of calcium, silica and alumina. Alkaline solution are from soluble sodium-based used in geopolymerization are combination of Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3). The mortars samples were cast with various concentration of NaOH and ratio of Na2SiO3 /NaOH which is 2.5. The specimens were carried out on size 50x50x50 mm cube and fresh mortar were been cured at 70 ̊c oven temperature and ambient temperature. The compressive strength tests were conducted after aging the specimen at 3, 7, 14, and 28 days. The results revealed that as the concentration of NaOH increased, the compressive strength of geopolymer mortar increases. However, the optimum NaOH concentration of geopolymer mortar is at 12M. More than 12M concentrations of NaOH were produced high porosity and decreasing the strength. Moreover, curing of fresh geopolymer mortar is performed mostly at an oven temperature compared to ambient temperature due to heat being a reaction accelerator. This paper also present on the morphology, and Energy dispersive x-Ray (EDX) composition analysis of WPSA based geopolymer mortar.
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Sun, Zengqing, and Anya Vollpracht. "Leaching of monolithic geopolymer mortars." Cement and Concrete Research 136 (October 2020): 106161. http://dx.doi.org/10.1016/j.cemconres.2020.106161.
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