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Geopolymer Flat Slabs with Synthetic Coarse Aggregate under Punching
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This paper experimentally analyzed the behavior of steel fibers reinforced geopolymer with red mud synthetic coarse aggregates. Eight flat slabs were manufactured and subjected to symmetrical punching tests until failure. The results were compared with the estimates of the prescriptions of seven models in the literature. The results show a considerable increase in the punching shear capacity in the group with steel fiber addition; the strength gains in steel fiber reinforcement concrete were 9% and 36% for natural and synthetic aggregates, respectively, and 3% and 27% in geopolymer-reinforced concrete. However, the highlight of the post-peak behavior improvement was with the geopolymer concrete, while the slabs with synthetic aggregate showed similar behavior to conventional concrete slabs, and the theoretical models showed satisfactory predictions in favor of safety and can be applied to geopolymer concrete.
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Tailings from bauxite extraction are worldwide of environmental concern, due to their open-air disposal in landfill dams. Although numerous studies have been dedicated to the application and reuse of wastes from bauxite processing tailings, there is still an important gap regarding the identification of properties that may, enable its application in the development of materials, especially as construction elements. The objective of this research is to characterize environmentally and microstructurally the bauxite waste from processing tailings produced in the state of Pará, Brazil, aiming at a combined characterization and discussion that evaluates its potential applications, as possible alternative to simple disposal in landfills. Chemical characterization analyzes were performed by X-ray fluorescence (XRF), mineralogical by X-ray diffraction (XRD), morphological by Scanning Electron Microcopy (SEM) and Transmission Electron Microscopy (TEM) combined with Energy Dispersive Spectroscopy (EDS). In addition, physical analyzes were performed by granulometry, surface area measurement (BET) and Luxán pozzolanicity. Environmental analyzes were carried out through solubilization and leaching. The results obtained by chemical and mineralogical analyzes indicate that the material is an aluminosilicate with a high content of amorphous components, which allows it to be used as a pozzolan in either cementitious materials or as a precursor in alkali activated materials or else as a plasticity reducer in red ceramics. The results were confirmed by thermal analysis and by pozzolanicity test. Thus, it is possible to conclude, based on the characterization of the bauxite waste, that the material has potential for use in alternative construction materials, contributing to the sustainable development of civil construction.
This experimental investigation presents results and a discussion on a series of four reinforced concrete pile caps with and without steel fibers, measuring 400 × 400 × 1000 mm³, which were tested under concentric loading. The study set the steel fiber and the inclined shear reinforcement as variables. The fiber volume fraction was 1.5%, and the concrete compressive strength was 25 MPa. The results showed a tendency to increase ductility and ultimate strength with the use of inclined shear reinforcement; the same behavior was observed with the addition of steel fibers, improving the performance of the tested pile caps. This study opens the possibility of designing slender pile caps, especially when associated with both analyzed parameters.
This research investigates the properties of alkali-activated materials (AAMs) using sodium metasilicate, with the ratio of SiO2:Na2O equals 1. This study was conducted to achieve the following three aims. Firstly, to understand the solubility mechanism of granular sodium metasilicate pentahydrate (Na2SiO3.5H2O) when used in a one-part mixing method. Secondly, to investigate the properties of AAMs when a sodium metasilicate aqueous solution is used as an alkaline material and as a source of silica. Lastly, to study the retardation effect of sucrose on AAMs. This research used aluminum silicate precursors, such as low-calcium fly ash, slag, and micros silica, alkali activators, such as NaOH pellets and Na2SiO3.5H2O, and standardized sand. The alkaline activators were first dissolved in water using a water bath shaker to achieve the alkaline solution. Sucrose, which is about 2% of the weight of the solid precursors, was added to modify the reaction process between the precursors and the alkaline materials. Four types of samples were prepared: M1, M2, M3, and M4, with the fly ash, slag, and silica fume ratios of 80:20:0, 70:30:0, 75:20:5, and 100:0:0, respectively. The research conducted solubility test of the alkaline materials, flowability, 7-, 28-, 56-day compressive and flexural tests, drying shrinkage test of mortar samples, and the setting tests of pastes with and without sucrose. The results show that the dissolution time of the NaOH was much shorter, whereas Na2SiO3.5H2O needed a solvent with a temperature of around 40°C to be fully dissolved. This problem of solubility decreases the quality of AAMs formed using the one-part mixing method. Among the mortar samples, the M4 had the highest flow rate, while M3 had the lowest flow rate. M2 had the highest compressive and flexural strength of 43.4 MPa and 6.1 MPa, respectively. The setting time test shows that sucrose retards the reaction process in AAM.
This paper presents an experimental study on the behaviour of the bond stress of steel reinforcing bars embedded in steel-fibre-reinforced concrete. In total, 27 specimens were subjected to pull-out tests. The main variables included the volumetric fraction of the fibre, the diameter of the reinforcing bars and the anchorage length. The results showed that the introduction of steel fibres had a significant effect on improving the bond stress performance in terms of the failure load resistance, the tensile resistance of the concrete and the reduction in the anchorage length, resulting in a more ductile bonding behaviour of reinforcing bars with smaller tested diameters. An equation to estimate the ultimate bond stress was proposed based on the prescriptions of the Brazilian design code NBR 6118, which is more accurate and considers the observed effects of the fibre addition.
Alkali-activated materials (AAM) are recognized as potential alternatives to ordinary Portland cement (OPC) in order to limit CO2 emissions as well as beneficiate several wastes into useful products. However, the alkali activation process involves concentrated aqueous alkali solutions, which are corrosive, viscous, and, as such, difficult to handle and not user friendly. Consequently, the development of so-called one-part or "just add water" AAM may have greater potential than the conventional two-part AAM, especially in cast-in-situ applications. One-part AAM involves a dry mix that consists of a solid aluminosilicate precursor, a solid alkali source, and possible admixtures to which water is added, similar to the preparation of OPC. The dry mix can be prepared at elevated temperatures to facilitate the reactivity of certain raw materials. This review discusses current studies of one-part AAMs in terms of raw materials, activators, additives, mechanical and physical properties, curing mechanisms, hydration products, and environmental impacts.
Geopolymer cement, high-alkali (K-Ca)-Poly(sialate-siloxo) cement, results from an inorganic polycondensation reaction, a so-called geopolymerisation yielding three dimensional zeolitic frameworks. High-tech Geopolymer K-Poly(sialate-siloxo) binders, whether used pure, with fillers or reinforced, are already finding applications in all fields of industry. These applications are to be found in the automobile and aeronautic industries, non-ferrous foundries and metallurgy, civil engineering, plastics industries, etc. Geopolymer cement hardens rapidly at room temperature and provides compressive strengths in the range of 20 MPa, after only 4 hours at 20°C, when tested in accordance with the standards applied to hydraulic binder mortars. The final 28-day compres- sion strength is in the range of 70-100 MPa.The behaviour of geopolymeric cements is similar to that of zeolites and feldspathoids; they immobilize hazardous materials within the geopolymeric matrix, and act as a binder to convert semi-solid wastes into adhesive solids. Their unique properties which include high early strength, low shrinkage, freeze-thaw resistance, sulphate resistance and corrosion resistance, make them ideal for long term containment in surface disposal facilities. These high-alkali cements do not generate any Alkali-Aggregate-Reaction. Preliminary study involving 27Al and 29Si MASNMR spectroscopy and the proposed structural model, reveal that geopolymeric cements are the synthetic analogues of natural tecto-alumino-silicates.
The use of column
capitals is one way to increase the punching strength of slab-column connections.
Recommendations presented by codes of practice for defining the geometry and
checking the resistance of slab-column connections with capitals are not comprehensive,
with few experimental studies available on the topic. This paper discusses important
aspects of the historical development of mushroom slabs and also presents experimental
results of 4 tests, with 1 test in a reference flat slab and 3 tests in mushroom
slabs with circular column capitals. These results are compared with theoretical
results estimated using Eurocode 2 (2004) and NBR 6118 (2007). They were also
compared with a series of non-linear finite element analysis in order to get
insight of the stress distribution and of the failure mechanism of mushroom
slabs.
The Bayer process is used for refining bauxite to smelting grade alumina (Al 2 O 3), the precursor to aluminium. The process was developed and patented by Karl Josef Bayer 110 years ago, and has become the cornerstone of the aluminium production industry worldwide. Production of alumina reached 46.8 megatonnes (Mt) worldwide by the end of 1997, with Australia the worlds largest producer of bauxite and refiner of alumina with just under 30% of world production. Although the refining process is well established and the basic theories underpinning it are well defined, the fundamental chemistry of the Bayer process is not well understood. Of particular interest to industrial and academic researchers alike, is the chemistry of the Bayer process solids — aluminium trihydroxide, 'red mud' and sodium oxalate. The surface chemistry of these solids is of great industrial importance as the refining industry experiences significant restrictions due to limitations imposed on the process by surface chemical reactions. Of scientific interest is the conceptual advancement of our knowledge and understanding of the nature of surfaces under extreme (non-ideal) conditions. A review of the current literature relating to these important Bayer process solids is thus presented. While not exhaustive, the review is thorough and aims to familiarise the reader with current levels of understanding regarding the nature of Bayer process solids surfaces under Bayer process conditions, and the significant roles these solids play in the overall efficiency of the refining process. It is hoped that this review will provide a useful starting point for researchers new to the area of Bayer process research, whilst also stimulating further fundamental research in this economically and scientifically significant area. © 1999 Elsevier Science B.V. All rights reserved.
Red mud (RM) is a mineral waste, residue of the Bayer process used to obtain alumina from bauxite. While the exploration of rolled pebble damages the environment and is much more controlled by the government, the huge RM disposal areas do not stop increasing and polluting soil, rivers and groundwater sources in Amazon. In this work, the material mixtures used to produce coarse aggregates presented up to 80% of RM, 30% of metakaolin and 30% of active silica as recycled waste. Several tests were carried out to determine the aggregates physical properties and to evaluate the mechanical performance of the concretes with the new aggregates, including hydraulic abrasion strength, and the results were compared to the reference ones, i.e. rolled pebble concretes. Additionally, the sintering process neutralizes any toxic substance as occur in some RM products like tiles and bricks, and these results have encouraged an industrial or semi-industrial production of RM aggregates for concretes.
The study was directed towards determining the usability of clay and fine wastes (CW and FW) of boron from the concentrator plant in Kirka (Turkey) as a fluxing agent in production of red mud (RM) brick. Both laboratory studies on the characterization of materials and industrial-scale tests for production of bricks were carried out. CW and FW, which have similar chemical composition but include different types and amounts of oxides, were added in amounts of 5, 10 and 15wt% to RM, which consists of high amounts of Fe2O3, Al2O3, SiO2 and alkalies. Six different sets of samples have been produced and fired at 700, 800 and 900°C. Dry shrinkage of green body, bending and compressive strength, firing shrinkage, water absorption, frost resistance and harmful magnesia and lime tests on heat-treated bodies have been performed. The mineralogical and mechanical tests showed that usability of boron wastes as a fluxing agent in the production of RM bricks was possible. In addition, the samples obtained by adding 15wt% CW and FW to RM showed the best mechanical characteristic.
Red mud (RM), the digestion by-product of bauxite processing from "Aluminum Hellas", was dewatered by means of a filter press. The filtrand with water content from 28 to 32 wt% was named ferroalumina (FA). In order to utilize it as a raw material in the production of Ordinary Portland Cement (OPC), mixtures were prepared with limestone, sandstone and 1, 3 and 5 wt% FA addition, respectively. The design of the mixtures was based on the cement's compositional indexes LSF, AM and SM. Burnability tests showed that less than 1 wt% free lime can be obtained in all cases for firing at 1450 degrees C, except for the mixture with 1 wt% FA addition, which requires 1550 degrees C. XRD analysis and optical microscopy examination showed that FA addition did not affect the mineralogical phases of the produced clinkers. The characterisation of the produced Portland cements indicated that differences on surface area, water requirement and setting time are negligible. Compressive strength results after 28 days of curing varies from 55 to 63 MPa, which ranks the produced cements in CEM I 42.5N category. More specifically, the cements with FA addition due to their relatively high 2-day strengths (>20 MPa) can be ranked in CEM I 52.5N category. Addition of FA increases the amount of water-soluble chromium proportionally to the amount of total chromium to the mixture; however, conversion of total Cr to hexavalent Cr remains practically constant, in the range of 32-35 wt%. The results indicate that FA can be used as raw material in the production of OPC up to 5 wt% according to the chemical composition of the other raw materials.
This paper treats an experimental study of shear problems in steel fiber reinforced concrete beams without shear reinforcement, where a specific groove in the shear span is used to specify the location of diagonal cracks, aiming to reduce the arch effect, controlling the critical crack inclination at 30◦, and evaluating the assertiveness of the normative shear strength predictions. The experimental program includes four (4) beams, varying the steel fiber ratio. The results showed that the mechanism was satisfactorily induced shear failure, as expected. Also, it was observed that the ratio av/d did not influence the proposed model significantly, such behavior was expected because the shear cracks observed in the beams were more pronounced after distance av/4, making the arching action and dowel action less effective in the ultimate shear strength value. The proposed model excelled in the accuracy of the normative predictions, with a coefficient of variability between 4 and 8 %, probably to eliminate any arch effect for the ratio av/d = 1.86. However, a simplified calculation model based on the fiber residual stress distribution along the considered inclined section was proposed, and it was noted that the proposal presented better results, with an average value of 1.0 and a coefficient of variation (CoV) of only 3 %. It also showed a mean of 1.02 and a CoV of 8 % compared to the experimental results from the literature. Thus, the proposed predetermined shear failure surface and the calculation model are viable alternatives to evaluate estimates for shear resistance even with shear reinforcement or steel fibers.
Many studies have recently been conducted to reduce the environmental influences of construction in industrial sectors. Recycling rubber as aggregate in concrete helps to reduce the environmental effects of waste automobile tires, and enhances the deformability of the concrete in structural applications such as slabs on grade and concrete pavements. This study aims at examining the reinforcement of rubberized concrete by a hybrid system of fibers comprising industrial steel fibers and steel fibers from waste tires. Six concrete mixtures with/without steel fibers were investigated, using 0, 20% and 40% by volume of waste tire rubber (WTR) particles as a substitute for natural aggregates. The fresh properties of these concrete mixes were evaluated using concrete slump and air content tests, as well as unit weight. Compressive and splitting tensile strengths at 7 and 28 days and flexural strength at 28 days were used to evaluate the hardened concrete properties. Concrete porosity and rapid chloride permeability tests were conducted to evaluate the concrete’s permeability, and its volume stability was assessed by examining free-drying shrinkage and restrained shrinkage. The results showed that, although the mechanical properties of the concrete were negatively impacted when a portion of the crushed rock and sand aggregates were replaced by rubber particles, it was possible to produce rubberized concrete with comparable mechanical properties and durability to conventional concrete when 40 kg/m³ of steel fibers was used in conjunction with 20% rubber. The flexural strain capacity and post-peak properties of the rubberized concrete containing 20% rubber and 40 kg/m³ steel fibers were substantially better than conventional concrete. In addition, the free drying shrinkage strain after 56 days for all mixes was low, below 457 micro-strain or 0.046%, and the presence of high quantities of rubber particles and/or steel fibers in the concrete ring specimens subjected to restrained shrinkage testing prevented the initiation and propagation of cracks. The outcome of this study highlights the potential of these combinations for use in concrete pavement and slab on grade applications.
Red mud (RM) and municipal solid waste incineration bottom ash (MSWIBA) are continually generated in large amounts all over the world. In this study, RM and MSWIBA were made into pellets by a disc pelletizer and then transformed to lightweight aggregate ceramsites by high-temperature sintering. The sintering mechanism and optimal production process were revealed from evaluation of the performance of ceramsites produced under different production processes. The results showed that as the proportion of RM increased, the required sintering temperature increased at least by 7.34%, while the apparent density, bulk density, strength, porosity, proportion of macropores and pH of ceramsites reduced up to 9.46%, 9.45%, 68.56%, 77.36%, 93.75% and 3.43%, respectively. On the other hand, with the increase in sintering temperature, the apparent density and bulk density of ceramsites made from calcium-rich red mud (CRM) generally increased while the water absorption and pH generally decreased. The strength, however, first increased up to 27.11 MPa and then decreased to 17.48 MPa. When the ratio of MSWIBA and CRM was 1:1 and the sintering temperature was 1070 °C, the ceramsites produced could achieve the best performance with a bulk density of 1046.73 Kg/m3, an apparent density of 1783.44 Kg/m3, a particle strength of 27.11 MPa, a 1-hour water absorption rate of 0.8%, and a pH of 8.9. The ceramsites, for use as lightweight aggregates, can be a promising construction material in particular counting the benefits of waste recycling.
Shortage of aggregates is becoming a prominent issue in the construction industry due to rapid urbanization. In this study, artificial aggregates were produced with high-volume red mud and fly ash as blended aluminosilicate precursors. The mechanical properties, densities, and internal structures of the fabricated artificial aggregates were characterized, as well as the microstructure analysis and product identification. Through the quantitative analysis of X-ray computed tomography (XCT) images, the obtained pore data indicated that there was a hollow structure inside the artificial aggregates. The results showed that the optimal artificial aggregates could be possible candidates for mortar and concrete preparation.
The International Federation for Structural Concrete (fib) is a pre-normative organization. 'Pre-normative' implies pioneering work in codification. This work has now been realized with the fib Model Code 2010. The objectives of the fib Model Code 2010 are to serve as a basis for future codes for concrete structures, and present new developments with regard to concrete structures, structural materials and new ideas in order to achieve optimum behaviour. The fib Model Code 2010 is now the most comprehensive code on concrete structures, including their complete life cycle: conceptual design, dimensioning, construction, conservation and dismantlement. It is expected to become an important document for both national and international code committees, practitioners and researchers. The fib Model Code 2010 was produced during the last ten years through an exceptional effort by Joost Walraven (Convener; Delft University of Technology, The Netherlands), Agnieszka Bigaj-van Vliet (Technical Secretary; TNO Built Environment and Geosciences, The Netherlands) as well as experts out of 44 countries from five continents. © 2013 fédération internationale du béton/International Federation for Structural Concrete (fib). All rights reserved.
This paper presents a review of alkali-activation technology, moving from the atomic scale and chemical reaction path modelling, towards macroscopic observables such as strength and durability of alkali-activated concretes. These properties and length scales are intrinsically interlinked, and so the chemistry of both low-calcium (‘geopolymer’) and high-calcium (blast furnace slag-derived) alkali-activated binders can be used as a starting point from which certain engineering properties may be discussed and explained. These types of materials differ in chemistry, binder properties, chemical structure and microstructure, and this leads to the specific material properties of each type of binder. The secondary binder products formed during alkali-activation (zeolites in low-Ca systems, mostly layered double hydroxides in alkali-activated slags) are of significant importance in determining the final properties of the materials, particularly in the context of durability. The production of highly durable concretes must remain the fundamental aim of research and development in the area of alkali-activation. However, to enable the term ‘highly durable’ to be defined in a satisfactory way, the underlying mechanisms of degradation—which are not always the same for alkali-activated binders as for Portland cement-based binders, and cannot always be tested in precisely the same ways—need to be further analysed and understood. The process of reviewing a topic such as this will inevitably raise just as many questions as answers, and it is the intention of this paper to present both, in appropriate context.
As part of the research effort to develop cementless alkali-activated concrete using 100% fly ash as a binder, this paper aims to examine the effects of chemical changes of alkaline activators on the compressive strength of mortar and to analyze the microstructure of the mortar through SEM, EDS, XRD, FT-IR and by porosity assessments. The results showed that chemical changes of the alkaline activators had a significant effect on the early strength with higher molarity. In addition, the analysis of the structure through SEM and EDS indicated that the components having a considerable influence on the structure of the mortar were the Al and Si components. The XRD results revealed that there were no practical differences in the intensity according to the differences in the chemical components of the alkaline activators. On the other hand, the FT-IR analysis made it possible to identify changes in the chemical combination of SiOSi and SiOAl compared to fly ash and hardened mortar. The analysis of the porosity enabled us to verify indirectly the remarkable mechanical performance which was obtained by the activation of polymerization according to the chemical components of the alkaline activators. A relationship between the compressive strength and the splitting tensile strength of fly ash-based geopolymer concrete is proposed.
An experimental test program has provided the basis for the mechanical model presented here to estimate the punching resistance of axisymmetric reinforced concrete slabs subjected to concentrated loads or reactions. The proposed model has the advantages of describing the slab behavior beyond the cracking stage and of estimating both punching and flexural capacities of such slabs. Material characteristics are defined by generally accepted stress-strain relationships for uniform stress states and a formulation dependent on the stress gradient for the stress concentration region near the column or load. Failure criteria are expressed in terms of limiting strains or the limit at which tension is developed in the critical region of concrete. The dependence of the theoretical punching resistance on the influential parameters is illustrated and compared with the predictions of codes of practice. Finally, calculated and experimental punching strengths are compared and shown to correlate very well for a wide range of test slabs.
Bauxite residue (also called red mud) is the solid remainder of the bauxite industrial treatment by the Bayer process, which is universally applied for the aluminum production. The increasing public awareness for the environment is an incentive for establishment of alternative practices prescribing the use of this material. A wide range of applications exists for re-use of bauxite residue, more or less systematic with significant beneficial effects. In this paper, the outline of an extremely successful pilot project of a road embankment construction using bauxite residue is given. Furthermore the laboratory investigation of the physical and strength properties of bauxite residue throughout the research project and the quality control tests during construction are presented.
Double-layer glass-ceramic/ceramic tiles made from bauxite tailings and red mud were prepared using a single firing powder processing route. The influence of the preparation method used for the green bodies on the microstructure and mechanical properties of the final products was investigated. The macroscopic appearance, microstructure, and mechanical properties indicated that the production of double-layer glass-ceramic/ceramic tiles may be an attractive method for recycling industrial waste into building materials.
Red mud (bauxite waste) emerge as by-product from the caustic leaching of bauxites to produce alumina and it causes serious problems such as storing and environmental pollution. In this study, red mud, which is the industrial waste of Seydişehir Aluminium Plant (Turkey), was investigated for use in the making of ceramic glazes in the ceramic industry. The chemical and the mineralogical investigations indicated that major constituents of the red mud were hematite (α-Fe2O3) and sodium aluminium silicate hydrate (1.01 Na2O.Al2O3.1.68 SiO2.1.73 H2O). The production of the porcelain, vitreous (sanitary ware glazes), tile and electroporcelain glazes was done using the red mud. The glazes, which contain different compositions and properties, were examined. Their surface properties, the chemical strength of glazes in 3% HCI and 3% NaOH and abrasion resistance were investigated experimentally. It was found that the addition of up to 37 wt% of the red mud waste was possible in the production of the glazes.
Some potential uses of red mud as a raw component in clay mixtures for ceramic bodies production are presented. The influence of increasing amounts of red mud on the forming procedure, sintering and final properties was analyzed. Samples were produced by uniaxial pressing and slip casting. Two different clays are used as basic materials, the former being currently employed for the production of bricks by extrusion, the second — almost pure Kaolin — for high quality ceramic manufacturing. In both cases the addition of red mud led to more deflocculated solid–water systems and an increase of the critical moisture content. Mixtures prepared with the first clay and red mud loads up to 50% were fired at 850°C. The red mud content did not influence the sample porosity while determining a strength decrease attributed to the inertness of red mud at the working temperature. Samples produced using the second clay and red mud (0 – 20%) were fired at 950 and 1050°C. The addition of red mud determined increases of density and flexural strength which can be accounted for by the formation of a larger amount of glassy phase at higher red mud contents. The results of this work indicate excellent perspectives for using ‘red mud’ as raw material in mixtures with clay for the production of ceramic bodies.
Twelve sets of small scale fiber reinforced concrete (FRC) slab-column connections were tested to investigate the effect of fiber reinforcement on the punching shear resistance of flat slabs. The parameters studied included type, content and aspect ratio of fibers, and span-depth ratio of the slab.The results indicate that the use of hooked steel fibers improves substantially the ductility of shear failure of slab-column connections, modifies their failure mode, favorably, from pure punching to flexural, and leads to a significant increase in their ultimate shear capacity. The increase in ultimate shear resistance varied almost linearly with the steel fiber content. While polypropylene fibers increase the ductility of shear failure, they are not as effective as steel fibers in increasing the punching shear resistance.Based on evaluation of the current test results and other experimental data reported in the technical literature, a design equation is proposed to predict the ultimate punching shear strength of slab-column connections containing deformed steel fiber reinforcement.
Cover title. Prepared as part of an investigation conducted by the Engineering Experiment Station, University of Illinois at Urbana-Champaign.
The aim of the present research work was to investigate the possibility of adding red mud, an alkaline leaching waste, which is obtained from bauxite during the Bayer process for alumina production, in the raw meal for the production of Portland cement clinker. For that reason, two samples of raw meals were prepared: one with ordinary raw materials, as a reference sample ((PC)Ref), and another with 3.5% red mud ((PC)R/M). The effect on the reactivity of the raw mix was evaluated on the basis of the unreacted lime content in samples sintered at 1350, 1400 and 1450 degrees C. Subsequently, the clinkers were produced by sintering the two raw meals at 1450 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the red mud did not affect the mineralogical characteristics of the so produced Portland cement clinker. Furthermore, both clinkers were tested by determining the grindability, setting time, compressive strength and expansibility. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of the red mud did not negatively affect the quality of the produced cement.
Investigating 21st Century Cement Production in Interior Alaska Using Alaskan Resources
- C Sonafrank
Shrinkage and Geopolymers
- Le Talludec
- C Phelipot-Mardelé
- A Lanos
Effect of Aggregate Types on Mortar Properties Produced with Geopolymer Binders
- K.-J Huenger
- D Kurth
- M Brigzinsky
Performance of Fly Ash Geopolymer Mortar Containing Clay Blends
- Lekshmi
Ambient Cured Geopolymer Binder in Road Pavement-Subgrade Stabilization as a Replacement of Conventional Cement
- D S Cheema
Concentrated Loads on Concrete Slabs
- C Forsell
- A Holmberg
Análise dos Mecanismos de Resistentes e das Similaridades de Efeitos da Aadição de Fibras de Aço na Resistência e na Ductilidade à Punção de Lajes-Cogumelo e ao Cisalhamento de Vigas de Concreto
- K M A Holanda
Analyse von Hochreinen Tonerden und der Einfluss von Verunreinigungen auf das Sinterverhalten
- Mörtel