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Journal articles on the topic 'Pozzolanic materials'
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1
Santana, Juan J., Natalia Rodríguez-Brito, Concepción Blanco-Peñalver, Vicente F. Mena, and Ricardo M. Souto. "Durability of Reinforced Concrete with Additions of Natural Pozzolans of Volcanic Origin." Materials 15, no. 23 (November 24, 2022): 8352. http://dx.doi.org/10.3390/ma15238352.
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In this work, the properties of concrete modified with dosages of natural pozzolans (NP) in substitution of cement or superfine aggregates were evaluated. Proportions of 20/80 pozzolan/cement or pozzolan/superfine aggregates were selected for the additions of quarry and tuff pozzolans. Pozzolanic activity, durability, compressive strength, characteristic resistance, settling consistency, density, electrical resistivity, depth of water penetration, accessible porosity, and carbonation and chloride penetration were determined for the resulting concrete mixtures, and they were subsequently compared to the values obtained for the reference concrete batches without additions. The results of the cementitious mixtures supplemented with tuff (PZT) and quarry (PZQ) pozzolans, expressed in mmol/L, are consistent with the pozzolanism test, with [Ca(OH)2]/[OH−] ratios at 7 days are 6.03/60.19 for PZQ and 1.78/92.78 PZT. In addition to the pozzolanic activity at these dosages, the characteristic resistance and durability parameters required by EHE-08 were verified. Particular attention was given to the determination of the diffusion of chloride ions, introducing an instrumental modification of the accelerated integral method. The modification provides values of diffusion coefficients similar to those obtained by the other methods with the advantage of greater stability and quality of the measurement.
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Villar-Cociña, Ernesto, Moisés Frías, Holmer Savastano, Loic Rodier, María Isabel Sánchez de Rojas, Isabel Fuencisla Sáez del Bosque, and César Medina. "Quantitative Comparison of Binary Mix of Agro-Industrial Pozzolanic Additions for Elaborating Ternary Cements: Kinetic Parameters." Materials 14, no. 11 (May 29, 2021): 2944. http://dx.doi.org/10.3390/ma14112944.
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In this research work, the quantitative characterization of a binary blend comprised of two pozzolans (sugar cane straw (SCSA)–sugar cane bagasse ashes (SCBA), bamboo leaf ash (BLAsh)–SCBA and paper sludge (PS)–fly ash (FA)) taking into account the calculated values of the kinetic parameters of the reaction in the pozzolan/calcium hydroxide system is shown. The paper shows the most significant and important results obtained by the authors in the quantitative assessment (calculation of kinetic parameters) of the pozzolanic reaction of different mixtures of pozzolanic materials that are residues from agriculture or industrial processes. This allows a direct and rigorous comparison of the pozzolanic activity of the binary combinations of materials. The values of the kinetic parameters (reaction rate constant or activation free energy) constitute a very precise quantitative index of the pozzolanic activity of the binary combinations of materials, which is very useful for its employment in the elaboration of ternary cements. This paper shows that the binary blends 1SCBA60Blash40, 1SCBA50Blash50, 1SCBA70Blash30 have a very high pozzolanic reactivity followed by PSLSFA, 2SCBA50SCSA50, PSISFA and SCWI.
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Seleem, H. H., A. M. Rashad, and B. A. El-Sabbagh. "Performance of Blended Cement Concrete against Seawater Attack." Advances in Science and Technology 64 (October 2010): 19–24. http://dx.doi.org/10.4028/www.scientific.net/ast.64.19.
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The current work reports the influence of synthetic seawater on some of the durability aspects of an ordinary concrete mixture (control) and six pozzolan-concrete mixtures. Three types of pozzolanic materials were employed; silica fume (SF), ground granulated blast furnace slag (GGBS) and metakaolin (MK). The pozzolanic materials were employed as an addition to cement in binary and ternary combinations. All mixtures were tested for strength deterioration ratio (SDR) after 3, 6, and 12 months of exposure to synthetic seawater, permeability was measured after 6 and 12 months of exposure. It was found through this investigation that pozzolans increase the ability of concrete to withstand aggressive environment and prevent most of the deterioration signs. The pozzolanic materials serve also to increase the strength and to minimize the strength loss (SDR) upon exposure to seawater. The pozzolanic materials led to reduce concrete permeability compared to control.
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Shi, Caijun. "An overview on the activation of reactivity of natural pozzolans." Canadian Journal of Civil Engineering 28, no. 5 (October 1, 2001): 778–86. http://dx.doi.org/10.1139/l01-041.
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Natural pozzolan is one of the oldest construction materials. Lime-pozzolan cements have been used for several thousands of years and have an excellent reputation for their durability. Pozzolans are being widely used as a cement replacement in Portland cement concrete. The use of pozzolans has the advantage of lower costs and better durability, but the disadvantage of a longer setting time and a slower early strength development. Different techniques have been tried to increase the reactivity of natural pozzolans to overcome these disadvantages. This paper has reviewed various methods used to activate the pozzolanic activity of natural pozzolans. All activation methods can be classified into three catalogues: thermal, mechanical, and chemical activation. A comparison based on strengthcost relationship indicates that the chemical activation method is the most effective and cheapest one.Key words: activation, reactivity, natural pozzolans, pozzolanic reaction, calcination, elevated temperature curing, chemical activators, strength, cost.
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Yagüe García, Santiago, and Cristina González Gaya. "Reusing Discarded Ballast Waste in Ecological Cements." Materials 12, no. 23 (November 25, 2019): 3887. http://dx.doi.org/10.3390/ma12233887.
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Numerous waste streams can be employed in different cement production processes, and the inclusion of pozzolans will, moreover, permit the manufacture of concrete with improved hydraulic properties. Pozzolanic materials can be added to Ordinary Portland Cement (OPC) in the range of 10%–20% by mass of cement. One such example is the phyllosilicate kaolinite (K), and its calcined derivative metakaolin (MK), incorporated in international cement manufacturing standards, due to its high reactivity and utility as a pozzolan. In the present paper, discarded ballast classed as Construction and Demolition Waste (C&DW) is reused as a pozzolanic material. Various techniques are used to characterize its chemical, mineralogical, and morphological properties, alongside its mechanical properties, such as compressive and flexural strength. Discarded ballast in substitution of cement at levels of 10% and 20% produced type II or IV pozzolanic cements that yielded satisfactory test results.
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Pontes, Jorge, António Santos Silva, and Paulina Faria. "Evaluation of Pozzolanic Reactivity of Artificial Pozzolans." Materials Science Forum 730-732 (November 2012): 433–38. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.433.
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Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability. This property results from the reaction between calcium hydroxide and silica and alumina based materials. Different types of natural and artificial pozzolans show pozzolanic activities that differ depending on the materials characteristics. Therefore, the study of this property, namely its reactivity with calcium hydroxide, reveals itself to be important in the selection of the type and content of these materials. This paper presents the results of several pozzolanic reactivity methods, applied to different pozzolanic materials. The selected pozzolanic methods include Chapelle method, Fratinni method and Strength Activity Index. Those tests have been applied to evaluate the reactivity of various kinds of artificial pozzolans. The correlation between the test methods are presented and discussed.
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Záleská, Martina, Milena Pavlíková, and Zbyšek Pavlík. "Classification of a-SiO2 Rich Materials." Materials Science Forum 824 (July 2015): 33–38. http://dx.doi.org/10.4028/www.scientific.net/msf.824.33.
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The powder materials containing active SiO2, which are used as pozzolanic active materials in cement mixtures, can be classified in consideration of their pozzolana activity, particle size or reactivity. In this paper, several types of metakaoline are studied using Frattini and modified Chapelle test for pozzolanic activity determination. The particle size analysis is measured using the laser diffraction analyser and the differences in the chemical composition are characterized by FTIR spectroscopy. The obtained data show influence of particle size and chemical composition of tested powders on their pozzolanic activity, which corresponds with the results of Frattini and modified Chapelle test.
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Sierra, Oscar M., Jordi Payá, José Monzó, María V. Borrachero, Lourdes Soriano, and Javier Quiñonez. "Characterization and Reactivity of Natural Pozzolans from Guatemala." Applied Sciences 12, no. 21 (November 3, 2022): 11145. http://dx.doi.org/10.3390/app122111145.
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The possibility of using pozzolanic materials as a partial substitute for Portland cement (PC) to develop mortars and concretes promotes environmental and economic benefits. The present paper includes an in-depth investigation into the characterization of natural pozzolans from Guatemala for the valorization of these materials. An exhaustive physico-chemical characterization of the starting materials was first carried out. Second, an analysis of the pozzolanic reactivity of both pozzolans was performed using an evolution test of the pH and electrical conductivity measurements and a Frattini test. Finally, pastes and mortars were manufactured with pozzolans T and R as a substitute for PC. The results of the pH and electrical conductivity measurements confirmed that natural pozzolans can be classified as low-reactivity. The Frattini test and the thermogravimetric analysis confirmed the pozzolanic behavior of natural pozzolans at 28 curing days. In the cement pastes, lime fixation was positive for a long curing period, which demonstrated that these pozzolans had medium–long-term pozzolanic activity, similar to fly ash (FA). The results were confirmed by mechanical assays. The mortars with 15%, 25%, and 35% substitutions of cement for pozzolans had strength gain percentages of around 13–15% at 90 curing days.
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Juimo Tchamdjou, Willy Hermann, Sophie Grigoletto, Frédéric Michel, Luc Courard, Toufik Cherradi, and Moulay Larbi Abidi. "Effects of Various Amounts of Natural Pozzolans from Volcanic Scoria on Performance of Portland Cement Mortars." International Journal of Engineering Research in Africa 32 (September 2017): 36–52. http://dx.doi.org/10.4028/www.scientific.net/jera.32.36.
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The aim of this paper is to assess the possibility of using natural pozzolans (NPs) from Cameroonian volcanic scoria as supplementary cementitious materials (SCMs) in the production of Portland cement mortars. Four natural pozzolans (Black Natural Pozzolan: BNP, Dark-Red Natural Pozzolan: DRNP, Red Natural Pozzolan: RNP and Yellow Natural Pozzolan: YNP) with 3600, 4500, 4700 and 5200 cm2/g Blaine fineness respectively were produced from different colors (Black, Dark red, Red and Yellow) volcanic scoria in a laboratory mill. Natural pozzolans were characterized with regard to particle size distribution, particle shape, electrical conductivity, X-ray fluorescence (XRF) and X-ray diffraction (XRD). The calcium hydroxide consumption by NPs was assessed firstly by electrical conductivity measurements of calcium hydroxide/NPs suspensions with calcium hydroxide excess. Evidence of pozzolanic reactivity of NPs is revealed in hydrated lime pastes, and low reactivity was observed in aqueous suspensions. The effects of 15, 25, and 35 wt.% of NPs as cement substitution on the properties of Portland cement mortars were investigated. Different properties were studied such as setting time, consistency, mechanical strength, pozzolanic activity, absorption by capillarity and resistance to carbonation. The reactivity of NPs was also assessed by means of the mechanical strength development of mortars. The results obtained show that pozzolanic and hydraulic reactions take place in OPC systems. The correlation between mechanical strengths and physical properties of NPs has been established. The study concludes that using DRNP and RNP at 15 wt. % cement replacement can ameliorate globally the performance of mortar. Using all NPs at 35 wt. % has negative effect on the fundamental properties of cementitious mortars.
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Nguyen, Hoang Canh. "STUDY OF THE EFFECTS OF GYMPSUM, POZZOLANIC ADDITIVE MIXTURES AND THEIR FINENESS ON THE STRENGTH OF PCB50 FICO CEMENT." Vietnam Journal of Science and Technology 56, no. 1A (May 4, 2018): 159. http://dx.doi.org/10.15625/2525-2518/56/1a/12517.
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In the study, raw materials including clinker, gypsum, pozzolan were separately milled on a ball mill (the ball mill size: φ500 mm × L500 mm, productivity: 5 kg / grinding time) to achieve the desired blaine fineness. A mixture is mixed at the calculated ratio includes of 90 % fineness clinker, 5 % fineness gypsum and 5 % fineness pozzolan (In it, pozzolanic additive is mixed at different fineness levels). The effects of the mixture of gypsum and fineness pozzolanic additive as well as the fineness of pozzolanic additive to strength of PCB50 Fico cement were investigated. The study shows that, pozzolanic additive have reduced the strength of cement. But, when pozzolanic additive is mixed with gypsum, this additive mixture has increased the strength of the cement at the late time (at the age of 28 days). The fineness of pozzolan has little effected on the early strength of cement.
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A. Ahmedai, Mutasim, Salih A. M. Ahmed, Yousif H. Ahmed, and El-Sharif M. Ibrahiem. "Tagabo Volcanic Ash as Cement Replacing Materials." FES Journal of Engineering Sciences 9, no. 2 (February 22, 2021): 35–39. http://dx.doi.org/10.52981/fjes.v9i2.674.
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This paper aims to assess the pozzolanic characteristics of the volcanic ash obtained from Jebal Tagabo (Tagabo Mountains) in western Sudan (North Darfur State) as potential Supplementary Cementitious Materials for use in blended cement and concrete. Four natural Pozzolanic materials samples have been obtained; the first is volcanic ash from the Garma region (TG1VA), the second from the Mabo region (TG2VA), the third from the Mawo region (TG3VA) and the last from the Daim Sanosi region (TG4VA). This study has investigated the chemical and physical characteristics of the samples and their pozzolanic activities with Ordinary Portland cement (OPC) at different substitution levels of cement by weights, which are 10, 20, 30, 40, and 50%. And the results of chemical analysis show that all samples can be classified as Class N according to the American standard ASTM C618. The strength activity indices of the four samples at 20% level were found to be 75, 84, 89, and 83% respectively. These results indicate that the Jebal Tagabo Pozzolans are potential supplementary cementitious materials for use in blended cement.
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Embong, Rahimah, Andri Kusbiantoro, Azrina Abd Wahab, and Khairunisa Muthusamy. "Soluble Pozzolanic Materials from Coal Bottom Ash as Cement Replacement Material." Key Engineering Materials 879 (March 2021): 68–80. http://dx.doi.org/10.4028/www.scientific.net/kem.879.68.
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Nowadays, intensive research in production of highly reactive pozzolanic materials from industrial waste to replace cement is crucial. This action expected to increase industrial waste recycling rate and at the same time reduce extraction of non-renewable resources of limestone. Unique characteristics of coal bottom ash as one of the industrial based pozzolan gained less popularity because of its low reactivity and heavy metal leaching due to conventional method used for disposal. Therefore, an alternative approach was deliberated in this research to utilize coal bottom ash into soluble form and enhance the quality of bottom ash as pozzolanic material. Coal bottom ash after the acid washing with optimum parameter was then undergoes solution-gelification process with various alkali based solution for 2 hours soaking durations. The conversion of coal bottom ash into soluble silica in this study demonstrates good pozzolanic performance in a state of siliceous gel pozzolan compared to the raw ones. 5% of cement replacement by soluble silica from CBA shows good strength development from early and later age. The physical dispersion effect is the cumulative effect of enhancement cement hydration due to the availability of increased the nucleation sites on soluble silica particles.
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Quarcioni, V. A., F. F. Chotoli, A. C. V. Coelho, and M. A. Cincotto. "Indirect and direct Chapelle's methods for the determination of lime consumption in pozzolanic materials." Revista IBRACON de Estruturas e Materiais 8, no. 1 (February 2015): 1–7. http://dx.doi.org/10.1590/s1983-41952015000100002.
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In this work, comments are made about indirect methods and direct Chapelle's method applied to the determination of the reactivity of pozzolanic materials. The Chapelle's method is based on the lime-pozzolan reaction and quantifies the pozzolanic reactivity of any material intended to be applied by the cement industry. This lime consumption determination by the pozzolan through this reaction can be made with mass proportions - lime:pozzolan 1:1, as originally proposed by Chapelle or 2:1, as specified in Brazilian and French Standards. Comparative results with both proportions are presented for sugar cane bagasse ash, rice rusk ash, silica fume, fly ash, and metakaolin, commonly studied in our country. Statistical calculations showed that for some materials of similar characteristics to the researched RHA, FA e MK at issue, essays carried out with only 1g of CaO may be underestimating the amounts of CaO consumed per gram of pozzolanic material that can be obtained. Comments were made about the Brazilian and French Standards based on this method and emphasized the expression of lime consumption per mass of the amorphous phase of these materials, as determined by X ray diffraction analysis with the Rietveld refinement method.
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Pavlíková, Milena, Pavla Rovnaníková, Martina Záleská, and Zbyšek Pavlík. "Diatomaceous Earth—Lightweight Pozzolanic Admixtures for Repair Mortars—Complex Chemical and Physical Assessment." Materials 15, no. 19 (October 3, 2022): 6881. http://dx.doi.org/10.3390/ma15196881.
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The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana active admixtures applicable in the concrete industry and the production of repair mortars applicable for historical masonry. The comprehensive experimental campaign comprised chemical, mineralogical, microstructural, and physical testing of raw materials, followed by the analyses and characterization of pozzolanic activity, rheology and heat evolution of fresh blended pastes, and testing of macrostructural and mechanical parameters of the hardened 28-days and 90-days samples. The obtained results gave evidence of the different behavior of researched diatomaceous earth when mixed with water and Portland cement. The differences in heat evolution, initial and final setting time, porosity, density, and mechanical parameters were identified based on chemical and phase composition, particle size, specific surface, and morphology of diatomaceous particles. Nevertheless, the researched mineral admixtures yielded a high strength activity index (92.9% to 113.6%), evinced their pozzolanic activity. Three fundamental factors were identified that affect diatomaceous earth’s contribution to the mechanical strength of cement blends. These are the filler effect, the pertinent acceleration of OPC hydration, and the pozzolanic reaction of diatomite with Portland cement hydrates. The optimum replacement level of ordinary Portland cement by diatomaceous earth to give maximum long-term strength enhancement is about 10 wt.%., but it might be further enhanced based on the properties of pozzolan.
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Y Priyanka,, V. Venkatadurga Raju and V. Bhargavi. "Study on Pervious Concrete by Partial Replacement of Silica Fume and GGBS with Cement and Addition of Glass Fibers." International Journal for Modern Trends in Science and Technology, no. 8 (August 7, 2020): 66–71. http://dx.doi.org/10.46501/ijmtst060813.
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Pervious Concrete for the pavements proves to be an effective and along- term solution for the universal problem of abnormal decrease of ground water table. Pervious Concrete has a unique mix design and giving special properties to the concrete which makes the concrete porous , allowing water from precipitation and other sources to pass directly through , there by reducing run off volume and increasing ground water table. Inorder to reduce the damage being caused to the environment by the use of cement , inpervious concrete , cement is replaced with pozzolanic materials such as GGBS , silica fume sand to increase strength and durability , glass fibers in stipulated ratio are added to the concrete mixture. In this study ,the mix designs such as M30 and PC30 are considered . The fine aggregate is replaced with coarseaggregate by different ratios like 0% , 5% , 10% ,15%. by adding different pozzolanic matrals like GGBS, silicafume with glassfibers. To find the effectiveness of the use of pozzolancic and glassfibes, compressive strength conducted. The following Conclusions can be summarized by analyzing tests performed on PC specimens. A significant reduction of workability. And A progressive addition in compressive strength by increasing the percentage of fine aggregates and pozzolanic materials in mix. The conclusion of fine aggregate content in the specimen increases the density and increase the pozzolanic materials addition. And addition of silica fume and GGBS in the mixtures improve strength , compressive strength increases even after adding pozzolanic materials. Due to increase of fine aggregate content. For all replacement levels of PC with other mixes goes on decreasing in strength when compared with parent grade ofM30. While comparing with PC with Pozzolanic materials, For 7 days there is a drastic change for same replacement, and for 28 days itshowssimilar trend for 25% pozzolanic concrete and goes on decreasing for strength for compressive strength. For all replacement levels of PC with pozzolanic goes on decreasing in strength when compared with parent grade of M30. Compressive strength slightly increased by adding glass fibers to the allmixes.
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Kim, Jae Jun, Sang Heum Youn, M. J. Cho, H. T. Shin, Jeong Bae Yoon, Kyu Hong Hwang, and D. S. Lee. "The Recycled Aggregates with Surface Treatment by Pozzolanics." Key Engineering Materials 287 (June 2005): 63–68. http://dx.doi.org/10.4028/www.scientific.net/kem.287.63.
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To improve the mechanical properties of concretes containing recycled aggregates, pozzolanic materials were used to decrease the porosity of the recycled aggregates. These pozzolanic materials were adhered on the surface of recycled aggregates and closed the open pores so that the water absorption was decreased 1~2% as the amount of adsorption was increased. Compressive strength of cement mortars and concretes using surface treated recycled aggregates reaches above 95% of the strength of its natural counterparts. Investigation of the microstructures using the scanning electron micrographs showed the formation of dense interface after the adsorption treatment of pozzolanics to recycled aggregates.
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Martín, Domingo A., Jorge L. Costafreda, Leticia Presa, José Zambrano, and Jorge L. Costafreda. "A New Study of the Lower Levels of the Los Frailes Caldera (Spain) for the Location and Characterisation of Pozzolans as Construction Materials." Construction Materials 2, no. 1 (January 25, 2022): 40–52. http://dx.doi.org/10.3390/constrmater2010004.
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Over the last two decades, there was been intensive study of pozzolans on the surface of the Los Frailes Caldera (Spain) for possible use as construction materials; however, research into the deepest underlying horizons has not yet been done. The main object of this paper is to present the results of the research carried out at different levels of depth, down to 30 m, to locate and demonstrate the presence of pozzolans in the depths of the Los Frailes Caldera. To achieve this, a series of analyses were carried out to classify the samples extracted from the various levels of depth, starting at the surface and continuing down to 30 m, which consisted of XRD, XRF, and SEM. Other technological tests were also performed such as chemical analysis of pozzolanic quality (CAQP) and pozzolanicity (PT) tests, at 8 and 15 days. Lastly, a geophysical study using electrical resistivity tomography (ERT) was developed to define the thickness and physical properties of the horizons of pozzolanic materials at depth, as well as to establish the depth of the deposit. The results obtained by XRD, XRF, and SEM confirmed the presence of pozzolans consisting of strongly zeolitized and bentonitised tuffs (ZBVT) in the lower levels of the Los Frailes Caldera, indicating that these horizons continue uninterruptedly beyond 30 m deep. The results of the CAQP and PT established that the ZBVTs that lie in the depths have pozzolanic qualities. On the other hand, the ERT study showed that ZBVT levels continue into the depths, thus proving that the lower limit of the deposit is even deeper. The results obtained in this work could have a positive impact on an increase in the reserves of pozzolanic raw materials in the researched area and could be used in the manufacture of light aggregates for mortars, concretes, and pozzolanic cements, consistent with the environment and effective in reducing CO2 emissions during the production process.
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Liguori, Barbara, Paolo Aprea, Bruno de Gennaro, Fabio Iucolano, Abner Colella, and Domenico Caputo. "Pozzolanic Activity of Zeolites: The Role of Si/Al Ratio." Materials 12, no. 24 (December 17, 2019): 4231. http://dx.doi.org/10.3390/ma12244231.
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A great challenge of research is the utilization of natural or synthetic zeolites, in place of natural pozzolans, for manufacturing blended cements. The difficulties of interpretation of the pozzolanic behavior of natural zeolite-rich materials and the role played by their nature and composition can be overcome by studying more simple systems, such as pure synthetic zeolites. This study aims at investigating the pozzolanic ability of isostructural zeolites with different framework compositions, such as three sodium zeolites of the faujasite (FAU) framework type: LSX, X, and Y. The pozzolanic activity has been estimated by thermogravimetry and X-ray diffraction analysis. The overall outcome of the investigation is that the zeolite structure affects its pozzolanic activity, as zeolites with similar framework densities exhibit distinct abilities to fix lime. Moreover, the framework composition is effective either from a kinetic point of view or on the total amount of fixed lime. Zeolite X appears to possess the best average features.
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Waghmare, Jagruti Dattatraya, Samruddhi Sampatrao Patil, Sheha Mahadeo Patil, and M. Maske. "Study and Review of Properties and Applications of Portland Pozzolana Cement." ASEAN Journal of Science and Engineering 1, no. 1 (August 23, 2021): 13–18. http://dx.doi.org/10.17509/ajse.v1i1.37980.
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Portland Pozzolana Cement (PPC) is prepared by adding Pozzolanic materials to ordinary Portland Cement. The artificial pozzolana materials used in the manufacturing of PPC such as fly ash, silica fume, rice husk, blast furnace slag, are actually industrial waste, which is produced in large amounts. These artificial pozzolana materials when used in concrete can reduce consumption of natural resources, diminish the effect of pollutants in the environment and it is economical and reliable. The main objective of this paper is to focus on the properties and applications of Portland Pozzolana Cement and make effective use of different industrial by-products in the manufacturing of cement. We found that both PPC and ordinary portland cement (OPC) are commonly used types of cement in construction. Nowadays, PPC is used as a substitute for ordinary Portland cement (OPC cement). Since PPC contains pozzolanic materials, it helps to enhance the strength of concrete. The quantity of PPC required in making the concrete is less when compared to OPC. PPC is a green material that contributes towards sustainable development.
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Qi, Gui Hai, and Xiao Qin Peng. "Analysis on the Pozzolanic Effects of Phosphorus Slag Powder in Concrete." Key Engineering Materials 477 (April 2011): 112–17. http://dx.doi.org/10.4028/www.scientific.net/kem.477.112.
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Phosphorous slag, one of the pozzolanic active materials, is a by-product from the production of yellow phosphorous. In this paper, phosphorous slag was ground and adopted to prepare concrete as a mineral admixture. Specific strength method was used to assess the influences of phosphorous slag content on the pozzolannic effects in concrete with different age. The results indicated that with the increase of phosphorous slag content and age, the pozzolanic effects were enhanced in concrete. Phosphorous slag powder is beneficial to the development of long-term strength of concrete.
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Kalinowska-Wichrowska, Katarzyna, Edyta Pawluczuk, Michał Bołtryk, and Adam Nietupski. "Geopolymer Concrete with Lightweight Artificial Aggregates." Materials 15, no. 9 (April 21, 2022): 3012. http://dx.doi.org/10.3390/ma15093012.
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This article presents the physical and mechanical properties of geopolymer concrete with lightweight artificial aggregate. A research experiment where the influence of fly ash–slag mix (FA-S), as part of a pozzolanic additive, on the properties of geopolymers was carried out and the most favorable molar concentration of sodium hydroxide solution was determined. The values of three variables of the examined properties of the geopolymer lightweight concrete (GLC) were adopted: X1—the content of the pozzolanic additives with fly ash + flay ash–slag (FA + FA-S) mix: 200, 400 and 600 kg/m3; X2—the total amount of FA-S in the pozzolanic additives: 0, 50 and 100%; X3—the molarity of the activator NaOH: (8, 10 and 12 M). In order to increase the adhesion of the lightweight artificial aggregate to the geopolymer matrix, the impregnation of the NaOH solution was used. Based on the obtained results for the GLC’s compressive strength after 28 days, water absorption, dry and saturated density and thermal conductivity index, it was found that the most favorable parameters were obtained with 400 kg/m3 of pozzolanic additives (with 50% FA-S and 50% FA) and 10 NaOH molarity. Changes in the activator’s concentration from 8 to 10 M improved the compressive strength by 54% (for a pozzolana content of 200 kg/m3) and by 26% (for a pozzolana content of 600 kg/m3). The increase in the content of pozzolanic additives from 200 to 400 kg/m3 resulted in a decrease in water absorption from 23% to 18%. The highest conductivity coefficient, equal to 0.463 W/m·K, was determined, where the largest amount of pozzolanic additives and the least lightweight aggregate were added. The structural tests used scanning electron microscopy analysis, and the beneficial effect of impregnating the artificial aggregate with NaOH solution was proved. It resulted in a compact interfacial transition zone (ITZ) between the lightweight aggregate and the geopolymer matrix because of the chemical composition (e.g., silica amount), the silica content and the alkali presoaking process.
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Kim, Jung J., Kwang-Soo Youm, and Jiho Moon. "A Study on Conversion Fraction and Carbonation of Pozzolan Blended Concrete through 29Si MAS NMR Analysis." Applied Sciences 10, no. 19 (September 29, 2020): 6855. http://dx.doi.org/10.3390/app10196855.
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The object of this paper is to investigate the carbonation resistance of concretes containing different pozzolanic materials. Three concrete mixtures that included fly ash, silica fume, and nanosilica were prepared, and the mixtures were designed to have similar mechanical properties to exclude the effect of mechanical properties on the carbonation. These pozzolanic materials in concretes have different silicate contents and grain size distributions. Rapid carbonation tests were conducted to investigate the durability of pozzolan blended concretes for carbonation, and the carbonation depth was measured at one, two, four, and eight weeks after 28-day water curing. 29Si NMR (nuclear magnetic resonance) experiments were performed, and the conversion fractions for each pozzolan blended concrete were extracted. The degree of carbonation was also assessed based on the Nuclear magnetic resonance (NMR) results.
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Xiao, Huigang, Fengling Zhang, Rui Liu, Rongling Zhang, Zhiguo Liu, and Hongxia Liu. "Effects of pozzolanic and non-pozzolanic nanomaterials on cement-based materials." Construction and Building Materials 213 (July 2019): 1–9. http://dx.doi.org/10.1016/j.conbuildmat.2019.04.057.
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Wong, John Kok Hee, Sien Ti Kok, and Soon Yee Wong. "Cementitious, Pozzolanic And Filler Materials For DSM Binders." Civil Engineering Journal 6, no. 2 (February 1, 2020): 402–17. http://dx.doi.org/10.28991/cej-2020-03091479.
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Deep Soil Mix (DSM) is a proven method of ground improvement for deeper underlying soft soil layers which are otherwise impractical to reach using conventional shallow soil stabilization and replacement methods. The predominant binder materials used are Ordinary Portland cement (OPC) and Lime (CaO) but negative effects to the environment from manufacture and increasing construction cost have prompted research into alternative materials. This review identifies pozzolans and filler materials as possible supplements or partial substitutes for better results. The DSM method and binder reaction processes during treated soil strength development are outlined and effectiveness of different pozzolans (Fly Ash, Silica Fume, Ground Granulated Blast Furnace Slag, Rice Husk Ash, Kaolin, and Metakaolin) and filler materials (e.g. fine sand) discussed together with their influence factors. With many pozzolans, a clear optimum dosage is observed where improved strength peaks. Aluminosilicate pozzolans perform better over siliceous pozzolans with Metakaolin (MK) identified as the most effective pozzolan for enhancing compressive strength. Up to date research results on these materials are compiled. MK blended cements are readily available and can be readily applied for initial field tests. Treated soil strength may be regulated with addition of filler materials to further reduce reliance on cement.
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Kim, Jae Jun, Sang Heum Youn, M. J. Cho, H. T. Shin, Jeong Bae Yoon, Kyu Hong Hwang, and D. S. Lee. "The Effect of Pozzolanics on the Recycled Aggregates by Surface Treatment." Materials Science Forum 486-487 (June 2005): 305–8. http://dx.doi.org/10.4028/www.scientific.net/msf.486-487.305.
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To improve the mechanical properties of concretes containing recycled aggregates, pozzolanic materials such as Silica Fume and Meta Kaolin were used to decrease the porosity of the recycled aggregates. These pozzolanic aterials were adhered on the surface of recycled aggregates and closed the open pores so that the water absorption was decreased 1~2% as the amount of adsorption was increased. Compressive strength of cement mortars and concretes using surface treated recycled aggregates reached above 95% of the strength of its natural counterparts. Investigation of the microstructures using the scanning lectron micrographs showed the formation of dense interface after the adsorption treatment of pozzolanics to recycled aggregates.
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Olonade, K. A., M. B. Jaji, and O. A. Adekitan. "Experimental comparison of selected pozzolanic materials." African Journal of Science, Technology, Innovation and Development 9, no. 4 (June 19, 2017): 381–85. http://dx.doi.org/10.1080/20421338.2017.1327931.
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Agarwal, S. K. "Pozzolanic activity of various siliceous materials." Cement and Concrete Research 36, no. 9 (September 2006): 1735–39. http://dx.doi.org/10.1016/j.cemconres.2004.06.025.
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Zaffar, Suhail, Aneel Kumar, Naeem Aziz Memon, Rabinder Kumar, and Abdullah Saand. "Investigating Optimum Conditions for Developing Pozzolanic Ashes from Organic Wastes as Cement Replacing Materials." Materials 15, no. 6 (March 21, 2022): 2320. http://dx.doi.org/10.3390/ma15062320.
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This research was performed to investigate the optimum conditions for developing pozzolanic ashes from organic wastes to be used as cement replacement materials. The organic wastes explored in the research are rice husk ash (RHA), wheat straw ash (WSA), and cow dung (CDA). When the organic waste is turned into ash, it develops a pozzolanic character due to the presence of silica. However, the presence of reactive silica and its pozzolanic reactivity depends on the calcination temperature, duration, and grinding. In this research, the organic wastes were calcined at three different calcination temperatures (300 °C, 400 °C, and 800 °C) for 2, 4, 6, and 8 h duration. The obtained ashes were ground for 30 min and replaced by 20% with cement. The samples containing ashes were tested for compressive strength, X-ray diffractometry (XRD), weight loss, and strength activity index (SAI). It was observed that the RHA calcinated at 600 °C for 2 h showed better strength. However, in the case of WSA and CDA, the most favorable calcination condition in terms of strength development was obtained at 600 °C for 6 h duration. The highest SAI was achieved for the mortar samples containing CDA calcinated at 600 °C for 6 h duration (CDA600-6H). The other two ashes (RHA and WSA) did not qualify as pozzolan according to the ASTM C618 classification. This was due to the presence of silica in crystalline form and lower surface area of the ash material. In this research, the ash was ground only for 30 min after calcination which did not contribute to an increase in the specific surface area and thus the pozzolanic activity. The materials ground for the higher duration are recommended for higher SAI.
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Madhkhan, Morteza, Armin Hamidi, and Navid Salehi. "Study on the Effects of Natural Pozzolan and Limestone Powder on Mechanical Properties of Roller Compacted Concrete Pavements." Advanced Materials Research 250-253 (May 2011): 3619–23. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.3619.
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Due to high maintenance and production costs of conventional asphalt pavements in recent years, substitution of concrete pavements has been taken into account. One important factor of such pavements is the long-term performance. The substitution of pozzolanic materials with existing cement in the mixture is a common choice to improve the durability factors and to increase the long term compressive strength. Owing to this change in cementitious materials, a general anticipation of the pozzolanic behavior to be observed is that the early age compressive strength gets decreased. On the other hand, this defect will be compensated in the long-term compressive strength. Furthermore, as conventional loads of road pavements are concerned, the tensile and flexural strengths have their own importance. Regarding these two factors, the related tests were also performed and the results were analyzed. The main purpose is to find the optimum material among these 2 types of pozzolanic supplements and its percentage of substitution with the preference of having the best average strength in both long and short term performances. Altogether, the natural pozzolan had better performance than limestone powder.
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Martín, Domingo A., Jorge L. Costafreda, Leticia Presa, Elena Crespo, José Luis Parra, Beatriz Astudillo, and Miguel Ángel Sanjuán. "Ignimbrites Related to Neogene Volcanism in the Southeast of the Iberian Peninsula: An Experimental Study to Establish Their Pozzolanic Character." Materials 16, no. 4 (February 13, 2023): 1546. http://dx.doi.org/10.3390/ma16041546.
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The speed at which climate change is happening is leading to a demand for new pozzolanic materials that improve the quality of cements and, at the same time, limit the emission of greenhouse gases into the atmosphere. The main objective of this work is the detailed characterization of an ignimbrite sample (IGNS) to demonstrate its effectiveness as a natural pozzolan. To meet this objective, a series of tests were carried out. In the first stage, mineral and chemical analyses were performed, such as petrographic analysis by thin section (TSP), X-ray diffraction (XRD), oriented aggregate (OA), scanning electron microscopy (SEM) and X-ray fluorescence (XRF). In the second stage, the following technical tests were carried out: chemical quality analysis (QCA), pozzolanicity test (PT) and mechanical compressive strength (MS) at 7, 28 and 90 days, using mortar specimens with ignimbrite/cement formulation (IGNS/PC): 10, 25 and 40% to establish the pozzolanic nature of the ignimbrite. The results of the mineral and chemical analyses showed that the sample has a complex mineralogical constitution, consisting of biotite mica, potassium feldspar, plagioclase, smectite (montmorillonite), quartz, volcanic glass, iron, titanium and manganese oxides, chlorite and chlorapatite. On the other hand, the technological tests revealed the pozzolanic nature of the sample, as well as visible increases in the mechanical compressive strengths in the three proportions, the most effective being IGNS/PC:10% and IGNS/PC:25% at 7, 28 and 90 days of setting. The results obtained could be applied in the formulation of new pozzolanic cements with ignimbrite as a natural pozzolanic aggregate.
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Belbachir, B., A. S. Benosman, and H. Taïbi. "Mineral-Based Composite Materials for Energy Efficiency in Buildings." Key Engineering Materials 678 (February 2016): 123–34. http://dx.doi.org/10.4028/www.scientific.net/kem.678.123.
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Degradation of building materials is an important phenomenon influencing their design and utilization. Mineral-based polymer-mortar composites (PMC) are often used as inexpensive promising materials to prevent the deterioration of constructions or remedy various reinforced concrete structures and they are used as materials for energy efficiency in buildings. In repair applications, polymer addition allows improving the adhesion properties of materials used in coating. With the intention of improving the sustainability of these composites, the influence of latex polymer and supplementary cementitious materials (natural pozzolan and silica fume) additions on the characteristics of these composites was investigated in aggressive media, such as acids. Mortars made with local pozzolanic mineral admixtures, obtained by substituting cement by different proportions of polymer (0, 5, 7.5, 10, 12.5 and 15%) were conserved in acidic solutions for 56 days. The microstructural analysis of these mortars was performed, using the X-ray diffraction technique, after 56 days of exposure to acid attack. The obtained results enable to bring out the beneficial effect of adding a latex polymer and other pozzolanic additives into modified materials on resistance to acid attacks. So, these composite materials can be recommended as materials for energy efficiency in buildings.
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Jia, Qiong, Jinsuo Lu, and Jing Yang. "Investigation on the feasibility of resource utilizing drinking water treatment sludge as a pozzolan to prepare cement-based materials." E3S Web of Conferences 267 (2021): 02006. http://dx.doi.org/10.1051/e3sconf/202126702006.
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The characteristics of four kinds of sludge obtained from different drinking water treatment plants in Australia and China were contrastively analyzed in this study using x-ray fluorescence, scanning electron microscopy, and x-ray diffraction. The conducted SAI test determined the pozzolanic reactivity of drinking water sludge ash (DWSA), which was derived from the grinding and calcination of drinking water treatment sludge (DWTS). The results indicated that the Al2O3 and SiO2 were the main components of DWTS, and the main crystalline minerals in DWTS were quartz, kaolinite, and aluminum sulfate hydroxide hydrate, which can be transformed into the reactive amorphous state after calcination at 800 ºC. Also, the SAI index of DWSA-derived mortar samples met the requirement, indicating a satisfying pozzolanic reactivity. Therefore, the DWTA was possible to be recycled as a pozzolan in cement-based materials.
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Cordeiro, Guilherme Chagas, Mônica Nunes Lemos, Kristian Vinco Xavier, and Charles Prado Ferreira de Lima. "Production of agroindustrial ashes with pozzolanic activity via acid leaching, conjugated burning and ultrafine grinding." Ambiente Construído 20, no. 4 (December 2020): 189–203. http://dx.doi.org/10.1590/s1678-86212020000400467.
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Abstract This paper aims to study the production and the physical and chemical characterization of rice husk, sugarcane bagasse, corn straw, and bamboo leaf ashes to use as pozzolans. The ash production steps basically consisted of raw material collection, chemical treatment by citric acid leaching, conjugated burning (thermal processing) and ultrafine grinding (mechanical processing) of the produced ashes. The results indicated that all ashes could be classified as pozzolanic additions based on specific standards. The high pozzolanicity of the ashes was confirmed by testing the electrical conductivity, mechanical performance index, and hydration kinetics of cement pastes by isothermal calorimetry. Therefore, the production processes used in this work were effective in producing highly reactive pozzolanic materials.
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Lin, Dung Hung, Huang Hsing Pan, Chang Geng Jiang, and Hui Chuan Hung. "Effect of Pozzolanic Materials and Poling Field on Electromechanical Coupling Coefficient of Cement-Based Piezoelectric Composites." Advanced Materials Research 512-515 (May 2012): 2867–72. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.2867.
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Electromechanical coupling coefficient of cement-based piezoelectric composites affected by pozzolanic materials and poling field are investigated. Specimens, through a pressure approach, are manufactured by combining PZT powders and cement-based binder with the same volume fraction. Pozzolanic materials including fly ash, slag and silica fume replace 20% cement in the binder. Three poling fields are considered to induce piezoelectricity of 0-3 cement-based composites. Results show that electromechanical coupling coefficients do not have many fluctuations in terms of material ages for any cement-pozzolanic piezoelectric composites. With the same volumetric substitutes of pozzolanic materials, the electromechanical coupling coefficient with pozzolanic materials except fly ash is lower than that with plain cement, especially for silica fume having a 7.9% decrease. Raising poling field can increase electromechanical coupling coefficients. Polarization of cement-based piezoelectric composites containing silica fume in low poling fields such as 0.5kV/mm and 1kV/mm is not easy to complete.
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Arroudj, Karima, Saida Dorbani, Mohamed Nadjib Oudjit, and Arezki Tagnit-Hamou. "Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials." International Journal of Engineering Research in Africa 34 (January 2018): 48–58. http://dx.doi.org/10.4028/www.scientific.net/jera.34.48.
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Much of the current research on concrete engineering has been focused on including siliceous additions as supplementary cementitious materials (SCMs). Silica reacts with Calcium hydroxide release during cement hydration, and produces more C-S-H. The latter contributes to increase compactness, mechanical strengths and sustainability of concrete. This paper explores the hydration characteristics of cement paste based on various natural mineral additions, that are very abundant in Algeria and present a high silica content (ground natural pozzolana “PZ” and ground dune sand “DS”). For this purpose, several analyses were carried out on modified cement pastes and mortars. TheseSCMswere introduced by replacement levels of 15, 20 and 25 by weight of cement. We first, studied the effect of these SCMs on the heat of hydration and mechanical strength of mortars at different ages. The evolution of hydration of modified paste was studied, by using Thermal analysis (TG/TDA) at different ages, to analyze the Calcium Hydroxide (CH) content of the modified pastes. It is shown that the CH content of the mixes including SCMs is lower than that of the plain cement paste, indicating that silica reacts with the cement paste through a pozzolanic reaction. Increased pozzolanic activity results in higher amounts of Calcium Silicate Hydrate in the paste, which in turn results in higher compressive strength for modified cement mortars. Due to its crystalline morphology, the ground DS particles present a partial pozzolanic effect, compared to PZ which is semi-crystalline. Modified mortars by 20% DS can be the optimal composition. It presents satisfactory results: good mechanical strength and low heat of hydration. It can lead to an economic and sustainable concrete. Ground DS is very abounded in Africa and free of any impurities and can be a good alternativeSCMsin cement industry.
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Rodríguez Bucio, J. L., José Luis Reyes-Araiza, Elia Mercedes Alonso Guzmán, Alejandro Manzano-Ramirez, R. Ramírez-Jiménez, W. Martínez Molina, C. Cobreros-Rodríguez, and L. Pérez Rea. "Study on the Pozzolanic Effect of Sugarcane Bagasse Ash from Taretan, Michoacán, Mexico, on a Portland Cement Mortar." Key Engineering Materials 668 (October 2015): 367–74. http://dx.doi.org/10.4028/www.scientific.net/kem.668.367.
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Since the construction industry is responsible for 30% of the CO2 emissions, one way to reduce the impact of the construction activity is to substitute ordinary Portland cement by pozzolanic materials. The application of using agricultural waste in the production of pozzolanic material is technically feasible, due to the calcination of organic materials and leaving ashes with a fine particle size and high SiO2 content. In the present, it is discussed the pozzolanic effect of sugarcane bagasse ash (SCBA) from Taretan, Michoacán, Mexico, on the physical and mechanical properties of a portland cement mortar. Test specimens were prepared based on replacing sugarcane bagasse ash percentages of 5, 10, 15, 20 and 30 %, relative to the weight of cement. To validate the mechanical properties of the specimens, tensile, flexural and compressive strength was determine. The porosity of the mortar was determined by means of non-destructive ultrasonic testing of pulse rate and electrical resistivity. The contribution of this paper was determine the bond strength of an overlay mortar with SCBA bonded to the concrete substrate by pull-out tests. The results showed that the addition of the sugarcane bagasse ash improved the mechanical strength, adherence of the mortar to concrete, and decreases the porosity on large curing times. Hence, it is suggested the use of Portland pozzolan cement containing sugarcane bagasse ash pozzolan, with the added benefit on the use of agricultural waste.
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Al-Kalili, Ahmed, Ahmed S. Ali, and Abbas J. Al-Taie. "A Review on Expansive Soils Stabilized with Different Pozzolanic Materials." Journal of Engineering 28, no. 1 (January 1, 2022): 1–18. http://dx.doi.org/10.31026/j.eng.2022.01.01.
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Soils that cause effective damages to engineer structures (such as pavement and foundation) are called problematic or difficult soils (include collapsible soil, expansive soil, etc.). These damages occur due to poor or unfavorited engineering properties, such as low shear strength, high compressibility, high volume changes, etc. In the case of expansive soil, the problem of the shrink-swell phenomenon, when the soil reacts with water, is more pronounced. To overcome such problems, soils can be treated or stabilized with many stabilization ways (mechanical, chemical, etc.). Such ways can amend the unfavorited soil properties. In this review, the pozzolanic materials have been selected to be presented and discussed as chemical stabilizers. The selected pozzolanic materials are traditional, industrial, or byproducts, ashes of agricultural wastes, and calcined-clay types. They are lime, cement, blast furnace slag, fly ash, silica fume, rice husk ash, sugarcane straw ash, egg ash, coconut husk ash, and metakaolin. In general, the stabilization of expansive soils with pozzolanic materials has an essential impact on swelling and Atterberg-limits and positively affects compaction and strength parameters. However, there is a wide range for the percentages of pozzolanic materials used as stabilizers. The content (15% to 20%) is the most ratios of the stabilizers used as an optimal percentage, and beyond this ratio, the addition of the pozzolanic materials produces an undesirable effect.
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Cheng, An Shun, Chung Ho Huang, Tsong Yen, and Yong Lin Luo. "Influences of Slag and Fly Ash on the Microstructure Property and Compressive Strength of Concrete." Advanced Materials Research 146-147 (October 2010): 1690–97. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1690.
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This research aims to investigate the pore structures and the interfacial transition zone (ITZ) of concrete containing both slag and fly ash. Test variables include three water-to-binder ratios (0.35, 0.50, 0.70) and four substitute ratios of cement with pozzolanic materials (20%, 30%, 50% and 60%). The specimens were tested to determine compressive strength, MIP porosity measurement and ITZ microhardness. Test results show that concrete containing slag and fly ash produce evident filling effect and the pozzolanic reaction after 28 days. At the age of 91 days the pozzolanic materials has provided prominent contribution to the strength, the porosity and the ITZ of concrete, making the pore volume smaller and ITZ property of pozzolanic concrete better than that of normal concrete. The concrete that adds suitable amount of pozzolanic materials (ex. 10% slag + 10% fly ash) has the optimum microstructure and mechanical property. Too much pozzolanic materials (ex. 40% slag + 20% fly ash) may be disadvantage to the concrete, and the suggested substitute ratio is under 50%. It is found that the compressive strength has the closest relationship with the total pore volume, so we use the total pore volume to predict the compressive strength of pozzolanic concrete and establish a prediction model as follow: S= -662.68Vt+87.29, R2=0.946.
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Wu, Ya Lei, Jun Jie Yang, Si Chen Li, and Man Wang. "Experimental Study on Mechanical Properties and Micro-Mechanism of All-Solid-Waste Alkali Activated Binders Solidified Marine Soft Soil." Materials Science Forum 1036 (June 29, 2021): 327–36. http://dx.doi.org/10.4028/www.scientific.net/msf.1036.327.
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Utilizing granulated blast furnace slag (GBFS), coal fly ash (FA), and furfural residue incineration ash (FRIA) as pozzolanic materials, then activated with calcium carbide residue (CCR) respectively to prepare all-solid-waste alkali activated binders (ASW binders). The laboratory tests were performed to research the effects of pozzolanic materials with different reactivity on the macro- and micro- characteristics of solidified marine soft soil. Results show that the mechanical properties and alkali-activation process of ASW binders solidified soil was determined mainly by the reactivity of pozzolanic materials, the higher reactivity of the pozzolanic materials in ASW binders couldn’t change the main hydration products, however, it would accelerate the hydrate reaction. The degree of hydrate reaction increased, the microstructure became denser with the increase of the reactivity of the pozzolanic materials in ASW binders solidified soil, on the macro- side, the strength and deformation modulus of the solidified soil increased, meanwhile, the brittleness of the solidified soil will be more obvious during the deformation resistance process. ASW binders (CCR:GBFS=1:1) solidified soil could reach the strength of cemented soil under the same conditions.
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Fard, Saeid Golizadeh. "HYBRID FIBER REINFORCED CONCRETE WITH POZZOLANIC MATERIALS." Journal of Cement Based Composites 1, no. 1 (March 11, 2020): 16–24. http://dx.doi.org/10.36937/cebacom.2020.001.004.
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This paper investigates the possibility of combining steel fibers with different weight percentages along with their functions in increasing compressive strength, indirect tensile strength and bending strength. It`s been considered an important economic issue for a long time the ability to service and increase the load-bearing capacity of structural materials. Concrete as a widely used structural material is widely used today. Despite its remarkable properties including high ductility, high durability, longevity, availability and low cost, concrete is a brittle material and performs extremely poor under flexural and tensile loads. In general, the breakdown and destruction of concrete is strongly dependent on the formation of cracks and micro-cracks. As the loading increases, the micro-cracks interconnect and form cracks. In order to address this problem and to create homogeneous conditions, a series of thin filaments has been used throughout the concrete in recent decades; They are called fibers. Steel fiber is one of the most commonly used fibers in concrete. In this study, the compressive strength of concrete was investigated which in some specimens reinforced with steel and containing pozzolanic materials, the compressive strength of control samples increased with the use of fiber etc. In the present study, the flexural and tensile strength of steel fiber reinforced specimens were investigated. According to the results, flexural strength increases with increase in steel fibers. The designs contain 1%, 1.5% and 2% of the Dramix hooked steel fibers used in the research. By reinforcing the specimens with steel fibers, the behavior of tensile concrete is much more flexible than that of non-steel specimens.
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Hanna, Kaissar M., and Aly Afify. "Evaluation of the activity of pozzolanic materials." Journal of Applied Chemistry and Biotechnology 24, no. 12 (April 25, 2007): 751–57. http://dx.doi.org/10.1002/jctb.5020241206.
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Bonavetti, V. L., V. F. Rahhal, F. Locati, E. F. Irassar, S. Marfil, and P. Maiza. "Pozzolanic activity of argentine vitreous breccia containing mordenite." Materiales de Construcción 70, no. 337 (February 17, 2020): 208. http://dx.doi.org/10.3989/mc.2020.04019.
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A vitreous breccia with variable amount of mordenite was studied for its use as pozzolan. The raw material was characterized by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and the zeolite content was estimated by the methylene blue staining technique. After being ground, physical characteristics, cation exchange capacity (CEC), pozzolanicity, and the compressive strength activity index (SAI) were determined. The staining technique and the CEC measurement were used to evaluate the average content of zeolite. The vitreous breccia has pozzolanic activity after 7 days, the water demand increases slightly, and its addition stimulates the early hydration of portland cement. At later ages, the pozzolanic reaction around the grains, as revealed by SEM studies, improves the compressive strength of blended cements having a SAI > 0.85 at 28 days.
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Lima, Cristian Jonathan Franco de, Francisco Roger Carneiro Ribeiro, Geraldo Cechella Isaia, and Mauricio Mancio. "Concretes with binary mixtures of artificial pozzolans and concrete demolition waste." Ambiente Construído 20, no. 4 (December 2020): 177–88. http://dx.doi.org/10.1590/s1678-86212020000400466.
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Abstract The objective of this study is to analyse the use of binary mixtures of pozzolanic materials and concrete demolition waste in concrete mixtures, especially the resulting mechanical properties and durability. A total of ten concrete formulations were produced distinguishing them in different types using different Portland cements, different artificial pozzolans and coarse aggregates from concrete demolition. The particular properties of each formulation were verified by testing the axial compressive strength, longitudinal modulus of elasticity and penetration of chloride under immersion. Substitutions were of 15% w.t. and 30% w.t. natural coarse aggregate substituted with concrete demolition waste and, in the case of binary mixtures, additional 25% w.t. of the binder agglomerate substituted with rice husk ash or fly ash. Results showed that the final strength to axial compression and modulus of elasticity of concrete mixtures were negatively affected by utilising demolition waste, but this effect was balanced by adding supplementary cementitious materials. Regarding the durability test, it was found that the lowest coefficients occurred in the mixtures using CP V-ARI, together with artificial pozzolans, in mixtures with 15% w.t. substitution of natural aggregate with recycled aggregate. It was concluded that using recycled aggregates in concrete is viable but conditioned to the concomitant use of pozzolanic materials.
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García Giménez, Rosario, Raquel Vigil de la Villa Mencía, Moises Frías, Sagrario Martínez Ramírez, Iñigo Vegas Ramiro, and Lucía Fernández Carrasco. "Cements based on kaolinite waste." Advances in Geosciences 45 (August 10, 2018): 133–38. http://dx.doi.org/10.5194/adgeo-45-133-2018.
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Abstract. The cement industry involves high-energy consumption that generates high CO2 emissions into the atmosphere. Environmental concerns can be addressed by replacing parts of Portland cement clinkers with pozzolanic materials in mortars and concrete. Slag, fly ash and silica fume are materials considered for the planned replacement. Research studies on clay minerals, such as kaolinite, are being followed with special attention by the scientific community and the cement industry. It is well known that these minerals require an activation process to transform kaolinite (K) into metakaolinite (MK). MK is an amorphous material from the transformation of K with high pozzolanic activity, which is its capacity to react with the portlandite released during the hydration of Portland cement, generating compounds such as C–S–H gels and some aluminum-phase hydrates. One of the MK production methods is heat treatment controlled by kaolinite at temperatures in the range of 600–900 ∘C. Different residues have been used (coal mining, paper sludge and waste from a drinking water treatment plant) activated at 600 ∘C for 2 h to elaborate blended cements. Due to their good behaviour as future eco-efficient additions, this research is a study by x-ray fluorescence (XRF), x-ray diffraction (XRD) and scanning electron microscopy (SEM) of their influence on the performances of blended cement mixtures (binary and ternary one), with substitutions of pozzolan ratio at 28 days of hydration. The porosity of pozzolanic cements decreases because of the formation of hydrated phases during pozzolanic reaction.
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Wilińska, Iwona, Barbara Pacewska, and Valentin Antonovič. "Hydration Processes of Four-Component Binders Containing a Low Amount of Cement." Materials 15, no. 6 (March 16, 2022): 2192. http://dx.doi.org/10.3390/ma15062192.
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Results of research on hydration of four-component binders containing very high amounts of supplementary cementitious materials were presented. The samples were composed of blended pozzolana (a mix of conventional fly ash and spent aluminosilicate catalyst), cement (about 20 wt.% in the binder) and Ca(OH)2. Spent aluminosilicate catalyst was proposed as activating component which can improve properties of low-cement blends, while the role of Ca(OH)2 was to enhance pozzolanic reaction. Early and later hydration periods of such blends were investigated by calorimetry, TG/DTG, FTIR and X-ray diffraction. Initial setting time as well as compressive strength were also determined. It was concluded that enhancement of reactivity and improvement of properties of fly ash–cement binders are possible by replacing a part of fly ash with more active fine-grained pozzolana and introducing additional amounts of Ca(OH)2. The spent catalyst is mainly responsible for accelerating action during the first hours of hydration and for progress of early pozzolanic reaction. Fly ash develops its activity over time, thus synergic effect influences the later properties of composites. Samples containing blended pozzolana exhibit shorter initial setting times and higher compressive strength, as well as faster consumption of Ca(OH)2 compared to the reference. Investigated mixtures seem to be promising as “green” binders, alternatives to cement, after optimizing their compositions or additional activating procedure.
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de Souza Soares, Marcela Maira Nascimento, Roberto B. Figueiredo, Maria Teresa Paulino Aguilar, and Paulo Roberto Cetlin. "Evaluation of Pozzolanic Activity of Siliceous Materials Using the Method of Variation of Conductivity in Lime Solution." Materials Science Forum 798-799 (June 2014): 363–68. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.363.
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Pozzolanic materials react with lime produced during curing of cement forming a hard phase similar to hardened cement. There are multiple methods to evaluate the pozzolanic activity of materials and one of these methods is the evaluation of the conductivity in lime solution. This method does not follow a standard procedure and there are multiple parameters that affect the results. The present paper summarizes some of the variations in this method reported in the literature and shows experimental results from tests in siliceous materials with crystalline (sand) or amorphous (silica fume) structure. The test is also used to evaluate the pozzolanic activity of sugar-cane bagasse ash. The effects of temperature, sample size and solution agitation are reported. The results indicates this method permits a rapid evaluation of pozzolanic activity but the testing parameters must be rigorously controlled.
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Cedrim, Felipe Araujo, Guilherme Augusto de Oliveira e Silva, Tiago Assunção Santos, and Daniel Véras Ribeiro. "Pozzolanicity Evaluation of Mineral Additions by Electrical Conductivity Measurements." Materials Science Forum 881 (November 2016): 239–44. http://dx.doi.org/10.4028/www.scientific.net/msf.881.239.
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The search for alternative materials that can replace Portland cement promotes discussion about the use of pozzolanic materials in cementitious matrices. Several techniques and procedures can determine the pozzolanic properties of a particular material based on electrical conductivity. Being an innovative and a subject of demand and minimum resource method, this article seeks validation by the comparison with chemical titration tests. To this end, were tested several possible pozzolanic materials (silica fume, metakaolin and eucalyptus ash) through the mentioned techniques
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Costafreda, Jorge Luis, and Domingo Alfonso Martín. "Bentonites in Southern Spain. Characterization and Applications." Crystals 11, no. 6 (June 20, 2021): 706. http://dx.doi.org/10.3390/cryst11060706.
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The objective of this work was to investigate and demonstrate the pozzolanic properties of the bentonites found at the San José–Los Escullos deposit, located in the southeast of the Iberian Peninsula, to be used in the manufacturing of more durable and environmentally compatible pozzolanic cements, mortars and concretes. These bentonites are mainly composed of smectites, with montmorillonite as the main clay mineral. They were formed by the hydrothermal alteration of tuffs, volcanic glasses, dacites, rhyolites and andesites. For this research, samples were taken from outcrops on the south, north and west side of the San José–Los Escullos deposit, and in the Los Trancos deposit located 19.3 km to the northeast. All samples consisted of bentonites, except for a zeolite sample taken from the northern flank of the San José–Los Escullos deposit, which was used to contrast and compare the behaviour of bentonite in some of the analyses that were done. An investigation of the mineralogical, petrological, chemical and thermogravimetric characteristics of the samples was carried out using various methods, such as XRD, OA (Oriented aggregates), TGA, XRF, SEM and thin section petrography (TSP). In addition, a chemical analysis of pozzolanicity (CAP) was done at 8 and 15 days to determine the pozzolanic capacity of the samples. XRD, XRF, SEM and TSP studies showed that these bentonites have a complex mineralogical constitution, composed mainly of smectites of the montmorillonite variety, as well as halloysite, illite, vermiculite, biotite, muscovite, kaolinite, chlorite, mordenite, feldspar, pyroxene, amphibole, calcite, volcanic glass and quartz. Thermogravimetric analysis (TGA) established the thermal stability of the bentonites studied at above 800 °C. Chemical analysis of pozzolanicity (CAP) confirmed the pozzolanic character of the bentonites, exhibited in their reactive behaviour with Ca(OH)2. The pozzolanic reactivity increased significantly from 8 to 15 days. These results show that the materials studied can be used as quality pozzolans for the manufacture of pozzolanic cements, mortars and concretes.
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Memon, Shazim Ali, Saba Khan, Israr Wahid, Yekaterina Shestakova, and Muhammad Ashraf. "Evaluating the Effect of Calcination and Grinding of Corn Stalk Ash on Pozzolanic Potential for Sustainable Cement-Based Materials." Advances in Materials Science and Engineering 2020 (April 7, 2020): 1–13. http://dx.doi.org/10.1155/2020/1619480.
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In developing countries, one of the usual practices is the uncontrolled, open burning of corn stalk (CS) or its utilization as a fuel. It is known that the ash obtained under uncontrolled burning conditions constitutes blackish and unburnt carbon particles as well as whitish and grayish particles (representing crystallization of silica) due to over burning. However, controlling the burning process can improve the quality of ash produced to effectively use it in cement-based materials. Hence, this research was aimed at exploring the pozzolanic properties of corn stalk ash upon calcination and grinding, for it to be used in the manufacturing of sustainable cement-based materials. In order to obtain a suitable corn stalk ash (CSA), which can be used in cement/concrete, a research investigation consisted of two phases. In the first phase, calcination was carried out at 400°C, 500°C, 600°C, 700°C, and 800°C for 2 hours. The tests applied on the resulting ashes were weight loss, XRD, pozzolanic activity index (PAI), Chapelle, Fratini, and consistency. From XRD spectra, it was found that, at lower temperatures, silica remained amorphous, while it crystallized at higher temperature. Ash combusted at a temperature of 500°C possessed largest pozzolanic activity of 96.8%, had a Fratini CaO reduction of 93.2%, and Chapelle activity of 856.3 mg/g. Thus, 500°C was chosen as an optimum calcination temperature. In the second phase, the ash produced at 500°C was grinded for durations of 30, 60, 120, and 240 minutes to ascertain the optimum grinding times. Resulting ashes were examined for hydrometer analysis, Blaine fineness, Chapelle activity, and pozzolanic activity. Experiment outcomes revealed a direct relationship between values of Blaine fineness, surface area, Chapelle activity, PAI, and grinding duration. It was concluded that CSA can be used as a pozzolan, and thus, its utilization in cement/concrete would solve ash disposal problems and aid in production of eco-friendly cement/concrete.
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Chi, Mao Chieh, Ran Huang, Te Hsien Wu, and Toun Chun Fou. "Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement." Key Engineering Materials 629-630 (October 2014): 306–13. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.306.
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Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.