Artykuły w czasopismach: „Pozzolanas”

1

Hago, Abdel Wahid, Amer Ali Al-Rawas i Awadh Al-Sidairi. "Effect of the Fineness of Artificial Pozzolana (Sarooj) on the Properties of Lime-Pozzolana Mixes". Sultan Qaboos University Journal for Science [SQUJS] 7, nr 2 (1.06.2002): 251. http://dx.doi.org/10.24200/squjs.vol7iss2pp251-258.

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Strength development of lime-pozzolana mortars is affected by the fineness of the pozzolan. This paper examines the effect of the fineness of artificial pozzolana on the strength development of lime-pozzolana mixtures. An artificial pozzolana produced by calcining clays from Oman was used in this study. The artificial pozzolana is locally known as “Sarooj”, and is currently being used in a big project for the restoration of historical monuments undertaken by the Omani Ministry of National Heritage and Culture. The artificial pozzolana was ground to various degrees of fineness, blended with hydrated lime with a ratio of 3:1, and the resulting mortar was used to make hardened mortar cubes. Strength of mortar cubes was measured at ages of 7, 14, 28 and 90 days of casting. The experimental results show that good artificial pozzolanas show a linear correlation between the Blaine fineness of the artificial pozzolana and the compressive strength, but such relationship does not exists for weak type pozzolanas. The fineness of the artificial pozzolana has its most significant effect on delayed strength gain, with more pronounced effect for good type pozzolan.

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Santana, Juan J., Natalia Rodríguez-Brito, Concepción Blanco-Peñalver, Vicente F. Mena i Ricardo M. Souto. "Durability of Reinforced Concrete with Additions of Natural Pozzolans of Volcanic Origin". Materials 15, nr 23 (24.11.2022): 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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Tommasi, Paolo, Luca Verrucci i Tatiana Rotonda. "Mechanical properties of a weak pyroclastic rock and their relationship with microstructure". Canadian Geotechnical Journal 52, nr 2 (luty 2015): 211–23. http://dx.doi.org/10.1139/cgj-2014-0149.

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The geotechnical behaviour of very weak pyroclastic rocks controls both the failure mechanisms at the margins of rock mesas, where historic hill towns are often sited, as well as the stability of old underground cavities in urban areas of Central Italy. The study focuses on the mechanical behaviour of one of the pyroclastic materials forming the Orvieto mesa (pozzolana), not unlike other pozzolanas in Central and Southern Italy and other pyroclastites from volcanic districts worldwide. The mechanical properties under static conditions of this weakly cemented rock are reported. A petrographic and physical characterization of the material was preliminary conducted, followed by a wide range of mechanical tests: oedometer, uniaxial, and isotropic compression tests and indirect tensile tests. The stress–strain and strength behaviours of the pozzolana are highlighted and compared with those of the rock materials of the pyroclastic formation (tuff). The mechanical behaviour of the pozzolana is related to its physical and textural characters, with special reference to continuity of the groundmass and porosity. Finally, the role of the material behaviour at the field scale is discussed.

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Sinha, Dr Deepa A. "Pozzolanas- Evaluation of Silica Fume For Use in Concrete". Paripex - Indian Journal Of Research 3, nr 5 (15.01.2012): 82–84. http://dx.doi.org/10.15373/22501991/may2014/28.

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Shi, Caijun. "An overview on the activation of reactivity of natural pozzolans". Canadian Journal of Civil Engineering 28, nr 5 (1.10.2001): 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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Krivenko, Pavel, Myroslav Sanytsky i Tetiana Kropyvnytska. "Alkali-Sulfate Activated Blended Portland Cements". Solid State Phenomena 276 (czerwiec 2018): 9–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.276.9.

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Early strength of the blended Portland cements containing granulated blast furnace slag and natural pozzolanas (zeolite tuff, etc.) can be enhanced by the alkali-sulfate activation. High early strength of the blended Portland cements as a result of alkali-sulfate activation can be attributed to acceleration of pozzolanic reaction at the early stages and formation of more quantities of ettringite at the early stages of structure formation. The results of the study showed that with high amounts of sodium sulfate in the alkali-sulfate activator, contents of gypsum dihydrate as a setting regulator of the blended Portland cements could be reduced. The effect of sodium sulfate activator on properties of the blended Portland cements was studied and the results are discussed.

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Doleželová, Magdaléna, i Alena Vimmrová. "Porosity of the Ternary Gypsum-Based Binders with Different Types of Pozzolan". Key Engineering Materials 677 (styczeń 2016): 122–27. http://dx.doi.org/10.4028/www.scientific.net/kem.677.122.

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Ternary gypsum-binders with different types of pozzolan were stored in the water and in the air. Brick powder, microsilica and blast slag were used as a pozzolan admixture. The quantity of the pozzolan in the mixture was determined from the amount of the amorphous phase in the pozzolan. Mixtures with pozzolans do not lose strength when stored in the water. Porosimetry shows that the product of the pozzolanic reaction started to develop.

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Juimo Tchamdjou, Willy Hermann, Sophie Grigoletto, Frédéric Michel, Luc Courard, Toufik Cherradi i 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 (wrzesień 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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C. M., Ikumapayi, Akingbonmire S. L. i Oni O. "The Influence of Partial Replacement of Some Selected Pozzolans on the Drying Shrinkage of Concrete". Scientific Review, nr 511 (25.11.2019): 189–97. http://dx.doi.org/10.32861/sr.511.189.197.

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Concrete is prone to cracking and one of the major causes of cracking is drying shrinkage of the hardened concrete. This research work was carried out to study the influence of partial replacement of some selected pozzolans on the drying shrinkage of concrete. Four pozzolans used in this study, were made to replace cement at various percentages resulting in various concrete mixes. Setting time test was conducted for the various cement mixes using Vicat’s apparatus and drying shrinkage test was done for the concrete test specimens. The results of the setting time indicate that partial replacement of pozzolans with ordinary Portland cement increases both the initial and final setting time of cement as the percentage replacement increases. Similarly, drying shrinkage results show that concrete made with Groundnut Shell Ash (GSA) and Locust Bean Pod Ash (LBA) at 12% replacement will have a stable and better shrinkage resistance than the control at both 56 days and 90 days. Meanwhile, the control concrete gives a better drying shrinkage at 28 days curing. In conclusion, the results show that pozzolanas [Bamboo Leaves Ash (BLA), Locust Bean Pod Ash (LBA), Sugarcane Bagasse Ash (SBA) and Groundnut Shell Ash (GSA)] can successfully replace cement up to 12% without necessarily affecting the shrinkage ability of the produced concrete. It also shows that Groundnut Shell Ash (GSA), Locust Bean Pod Ash (LBA) and Bamboo Leaves Ash (BLA) are more resistance to drying shrinkage than the control.

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Jamellodin, Zalipah, Mohd Saman Hamidah, Suraya Hani Adnan, Noor Shuhada Mohammad i Wan Yuslinda Wan Yusof. "Compressive and Flexural Strength of Fine Grained Mortar Containing Rice Husk Ash: A Review". Advanced Materials Research 1051 (październik 2014): 757–62. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.757.

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Fine Grained Mortar (FGM) offers a new innovative technology binder system to strengthen or repair concrete structures. The innovative technique is achieved by using a small maximum grain size of 1 mm for the mortars. Therefore, less than 2 mm of mortar thickness would be fitted between the strengthened layers. FGM also has high binder contents, by adopting different pozzolanic additives and high performance of plasticizers. Recently, the utilisation of supplementary of cementing materials such as Fly Ash (FA) and Rice Husk Ash (RHA) has a become an important in concrete industry. It has demonstrated significant influence in improving the strength of mortar. Most of the previous studies have focused on the FA to be replaced in the FGM. There is still lacking of research of using other pozzolanas in making FGM. This paper presents an overview on the use of FA and RHA as partial replacement of cement in mortar and FGM as well as future research that will be conducted by the authors.

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Merida, Ahcene, i Fattoum Kharchi. "Corrosion of the Pozzolan Concrete in Sulfates". Advanced Materials Research 911 (marzec 2014): 494–98. http://dx.doi.org/10.4028/www.scientific.net/amr.911.494.

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Sulfate attack and its effects are important from both scientific and industrial viewpoints. Itis perceived that cements containing pozzolan have better performance in sulfate solutions,since the pozzolanic reactions reduce the quantity of calcium hydroxide and increasecalcium silicate hydrate. This paper investigates the physical and mechanical properties ofconcretes made by blended cement containing Algerian natural pozzolan of volcanic origin, and Portland cement. in order to better determine the pozzolanic effect of the pozzolan addition in the concrete, the analysis of the experimental results of the effect of the partial replacement of the cement by the naturalpozzolana showed that it contributes positively to the improvement of its mechanical characteristics, its durability with respect to the permeability to the chlorine ions, the ultrasonic pulse velocity as well as the sulphate resistance. The present study confirms the pozzolanic reactivity of the natural pozzolans used.

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Igibah, Christopher Ehizemhen, Olugbenga Oludolapo Amu, Olumuyiwa Samson Aderinola i Lucia Omolayo Agashua. "Geopolymer Stabilization as Novel Technique of Reducing Carbon Dioxide Emissions". Scientific Review, nr 83 (20.07.2022): 42–50. http://dx.doi.org/10.32861/sr.83.42.50.

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The paper discusses geopolymerisation which is a chemical reaction within an alkaline solution as well as a solid reaction of both aluminium and silicon. It highlights the origin of silicates, pozzolanic composite or alumino-silicates that could be melted within alkaline solution that may be utilized as a source of geopolymers creation. Materials that possess plenty aluminium, silicon and others such as metakaolin, microsilica, pozzolanas, ashes, red mud, kaolin clay and slags can be used as raw materials with the activators to create geopolymers. Also geopolymer end product after the exothermic procedure carried out via oligomers, as well as three stages of geopolymerisation which are suspension, when hard or solid alumino-silicates matter and stuff is dissolved because of the occurrence of water together with alkali activator. After jettisoning a small quantity of water, the reorientation outsets, and then the cluster atoms take their position in the structure. In the course of the solidification at 200C (twenty Celsius degree) or higher temperature of roughly 10000C, the water (H2O) is almost absolutely jettisoned and the material displays his final look.

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13

Zhang, X., i G. W. Groves. "The beneficial effect of pozzolanas in suppressing the alkali-silica reaction". Advances in Cement Research 3, nr 9 (styczeń 1990): 15–21. http://dx.doi.org/10.1680/adcr.1990.3.9.15.

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Papatzani, Styliani, i Kevin Paine. "A Step by Step Methodology for Building Sustainable Cementitious Matrices". Applied Sciences 10, nr 8 (24.04.2020): 2955. http://dx.doi.org/10.3390/app10082955.

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In an effort to produce cost-effective and environmentally friendly cementitious binders. mainly ternary (Portland cement + limestone + pozzolanas) formulations have been investigated so far. Various proportions of constituents have been suggested, all, however, employing typical Portland cement (PC) substitution rates, as prescribed by the current codes. With the current paper a step by step methodology on developing low carbon footprint binary, ternary and quaternary cementitious binders is presented (PC replacement up to 57%). Best performing binary (60% PC and 40% LS (limestone)) and ternary formulations (60% PC, 20% LS, 20% FA (fly ash) or 43% PC, 20% LS 37% FA) were selected on the grounds of sustainability and strength development and were further optimized with the addition of silica fume. For the first time a protocol for successfully selecting and testing binders was discussed and the combined effect of highly pozzolanic constituents in low PC content formulations was assessed and a number of successful matrices were recommended. The present paper enriched the current state of the art in composite low carbon footprint cementitious binders and can serve as a basis for further enhancements by other researchers in the field.

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Vejmelková, Eva, Monika Čáchová i Jaroslava Koťátková. "Influence of Selected Pozzolanas on Basic Physical and Mechanical Properties of HSC". Materials Science Forum 824 (lipiec 2015): 39–42. http://dx.doi.org/10.4028/www.scientific.net/msf.824.39.

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Crushed brick (CB) used in high strength concrete as partial replacement of cement is the subject of this paper. It is a waste material and so its exploitation is needed to be found. Concrete industry can be proper area as CB is a fine material and is pozzolanic active. Basic physical properties and mechanical properties were investigated. Open porosity and bulk density achieved the best values when 30% of cement was replaced by CB. Matrix density decreased with rising addition ratio. The values of compressive strength was the highest for 30% replacement level and with 60% addition ratio were not lower than for the reference mixture. The conclusion is, that according to studied parameters 30% of cement substituted by CB is the most profitable addition ratio.

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Seleem, H. H., A. M. Rashad i B. A. El-Sabbagh. "Performance of Blended Cement Concrete against Seawater Attack". Advances in Science and Technology 64 (październik 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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Talero, Rafael. "Qualitative Analysis of Natural Pozzolanas, Fly Ashes, and Blast Furnace Slags by XRD". Journal of Materials in Civil Engineering 2, nr 2 (maj 1990): 106–15. http://dx.doi.org/10.1061/(asce)0899-1561(1990)2:2(106).

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Nair, Deepa G., K. S. Jagadish i Alex Fraaij. "Reactive pozzolanas from rice husk ash: An alternative to cement for rural housing". Cement and Concrete Research 36, nr 6 (czerwiec 2006): 1062–71. http://dx.doi.org/10.1016/j.cemconres.2006.03.012.

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Villar-Cociña, Ernesto, Moisés Frías, Holmer Savastano, Loic Rodier, María Isabel Sánchez de Rojas, Isabel Fuencisla Sáez del Bosque i César Medina. "Quantitative Comparison of Binary Mix of Agro-Industrial Pozzolanic Additions for Elaborating Ternary Cements: Kinetic Parameters". Materials 14, nr 11 (29.05.2021): 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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Lim, Andrew, Abdul Karim Mirasa, Hidayati Asrah i Xiaoping Tian. "MAXIMIZING VOLUME OF SPENT BLEACHING EARTH ASH (SBEA) POZZOLAN USED AS CEMENT REPLACEMENT IN MORTAR THROUGH MECHANICAL ACTIVATION". Jurnal Teknologi 84, nr 5 (26.07.2022): 105–16. http://dx.doi.org/10.11113/jurnalteknologi.v84.18177.

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Spent bleaching earth ash (SBEA) is harmful waste from the oil refining industry that has previously exhibited pozzolanic properties and potential for use as cement replacement. Conventional pozzolanic replacements in cements are typically limited to 30 % only as excessive amounts have detrimental on cement strength. This research aimed to investigate the feasibility of increasing the level of replacement past 30 % through mechanical activation. Preliminary investigations revealed that SBEA contains sufficient silica and alumina oxides to be classified as Class N pozzolan in accordance with ASTM C618. As expected with pozzolans, the use of SBEA in cement mortar improved the 28 and 56-day compressive strengths up to 30 % substitution but at the same time also increased the water requirement. Mechanical activation was able to improve the level of substitution to 50 % through a mix of increasing pozzolanic reactivity of SBEA as well as increasing the specific surface area of its particles.

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Yagüe García, Santiago, i Cristina González Gaya. "Reusing Discarded Ballast Waste in Ecological Cements". Materials 12, nr 23 (25.11.2019): 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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Griffin, Isobel. "Pozzolanas as Additives for Grouts - An Investigation of Their Working Properties and Performance Characteristics". Studies in Conservation 49, nr 1 (marzec 2004): 23–34. http://dx.doi.org/10.1179/sic.2004.49.1.23.

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Sierra, Oscar M., Jordi Payá, José Monzó, María V. Borrachero, Lourdes Soriano i Javier Quiñonez. "Characterization and Reactivity of Natural Pozzolans from Guatemala". Applied Sciences 12, nr 21 (3.11.2022): 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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Hassan, Maan S. "Adequacy of the ASTM C1240 Specifications for Nanosilica Pozzolans". Open Civil Engineering Journal 13, nr 1 (19.03.2019): 42–49. http://dx.doi.org/10.2174/1874149501913010042.

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Background: Nano-silica is a new pozzolan that is boosting the field of nanomaterials and can be used effectively in the concrete industry. ASTM C1240 is used to qualify silica fume pozzolans for use in concrete and for marketing purposes. Objective: The present study aims to assess the adequacy of ASTM C1240 in qualifying nanosilica for use in concrete and to introduce a modified procedure to measure the pozzolanic activity of nanosilica used with cementitious composites. Methods: The effects of various particle sizes and dosages on the compressive strength of blends in standard mortar were investigated. The correlation between the chemical reactivity and the compressive strength were also investigated using TGA and XRD analyses. The criterion conceived was validated at two ages: 7 days and 28 days. Results and Conclusion: The strength activity index results revealed that the following standard procedure ASTM C1240 is not applicable for nanosilica due to the high surface area and great pozzolanic reactivity of SiO2 nanoparticles, so a lower cement replacement percentage should be used. This study suggests that it be no more than 7%. The pozzolanicity testing results confirm that a nanosilica replacement level of more than 7% could not be effective in transforming further Portlandite into a C-S-H or other major cementing compound, leading to a “false negative” for nanosilica pozzolans.

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Kumator Josiphiah TAKU, Bilkisu H AMARTEY, Terhemba AGBER i Michael EGBUNU. "Evaluation of the suitability of plantain peel ash as a secondary cementitious material/ filler in mortar". World Journal of Advanced Engineering Technology and Sciences 8, nr 2 (30.04.2023): 287–92. http://dx.doi.org/10.30574/wjaets.2023.8.2.0096.

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The possibility of using Plantain Peel Ash (PPA) as a cementitious or filler material in partial replacement of cement for mortar and concrete was investigated in this research work. Plantain peels were collected in Idah in Kogi state and carbonated in the open air to reduce the carbon content after which it was calcined in a muffled furnace at 600oC for 3 hours. Samples were taken for oxide composition using XRF analysis. Ordinary Portland cement was partially replaced with PPA at 0, 5, 15, 20 and 25% replacement levels and the OPC-PPA mix used as binder material to produce mortar cubes at 0.5% Water to binder ratio and binder – aggregates ratio of 1:6, which were cured for 7, 14 and 28 days respectively and tested for compressive strength. Durability of the PPA blended mortar was evaluated using water absorption, Sorptivity and apparent porosity tests. The result shows that while specific gravity decreased with increasing percentage replacement from 3.1 to 1.2 for 0 to 25% PPA replacement respectively, standard consistency and setting times increased with increasing percentage replacement. The oxide composition of PPA gives a combined SiO2+Al2O3+Fe2O3 of 22.44%, which is less than the 50% required for pozzolanas. The compressive strength at 7, 14 and 28 days curing all increased with curing age but decreased as the percentage of ash increases, with only the mortar with 0% ash meeting the strength requirement for a class M mortar; and while the sorptivity increases with curing age and percentage replacement, water absorption and apparent porosity decreases with age but increases with percentage replacement. However, PPA blended mortars showed higher performance in acidic curing environment as compared to normal OPC mortars. It can be concluded on the basis of this research that while PPA does not meet the requirement of ASTM C618 for pozzolanas, it can be used as a filler material in concrete and mortar at up to 10% replacement of OPC to increase concrete durability when in acidic environment.

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Pfingsten, Johannes, Joerg Rickert i Klaus Lipus. "Estimation of the content of ground granulated blast furnace slag and different pozzolanas in hardened concrete". Construction and Building Materials 165 (marzec 2018): 931–38. http://dx.doi.org/10.1016/j.conbuildmat.2018.01.065.

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Desfitri, Erda Rahmilaila, Reni Desmiarti, Munas Martynis i Suci Rahma Dhani. "Analisis dan Karakterisasi Potensi Pozzolan Sebagai Sumber Silika (SiO2) Untuk Meningkatkan Nilai Sumber Daya Lokal". Jurnal Rekayasa Hijau 6, nr 2 (13.12.2022): 96–105. http://dx.doi.org/10.26760/jrh.v6i2.96-105.

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ABSTRAKKabupaten Padang Pariaman memiliki sumber daya pozzolan yang belum termanfaatkan secara optimal. Pozzolan adalah bahan yang mengandung senyawa silika dan alumina. Untuk pemanfaatan yang optimal dilakukan analisis dan karakterisasi potensi pozzolan sebagai sumber silika. Silika bisa dimanfaatkan untuk bahan baku utama diberbagai industri, seperti industri gelas, keramik, katalis, pertanian dan untuk pengolahan limbah. Untuk mengetahui potensi pozzolan sebagai sumber silika dilakukan analisis kualitatif dan kuantitaif menggunakan XRD dan XRF. Berdasarkan hasil analisis pola difraksi sinar-X dengan measurement program PANalitycal ditemukan senyawa SiO2 yang tertinggi teramati pada posisi 2θ sebesar 20o dan 26o. Sedangkan analisis XRF dilakukan untuk mendapatkan informasi jumlah elemen dan oksida logam yang terkandung pada pozzolan. Hasil analisi XRF menunjukkan bahwa kadar SiO2 yang terdapat pada pozzolan adalah sejumalh 62,56%. Senyawa lain yang ditemukan pada pozzolan diantaranya Al2O3, SiO2, P2O5, K2O, CaO dan Fe2O3. Hasil penelitian menunjukkan bahwa pozzolan sangat berpotensi untuk dijadikan sumber silika.ABSTRACTPadang Pariaman regency has pozzolanic resources that have not been utilized optimally. Pozzolan is a material containing silica and alumina. For optimal utilization, analysis and characterization of the potential of pozzolan as a source of silica have been done. Silica can be used as a raw material in several industries, for example, glass, ceramic, catalyst industry, farm, and waste treatment. Qualitative and quantitative analyses by XRD and XRF were carried out to investigate pozzolan as a source of silica. Based on x-ray diffraction pattern with measurement of PANalitycal program was found SiO2 compound on 2θ position, 20o dan 26odegree. XRF analysis is used to get information chemical composition of pozzolan. XRF analysis found silica composition is 62,56%. Other compounds also found in pozzolans such as Al2O3, SiO2, P2O5, K2O, CaO, and Fe2O3. The result shows that pozzolan in Padang Pariaman Regency has the potential as a source of silica.

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Blaise Ngwem Bayiha, Benjamin Bahel, Fabien Kenmogne, Ulrich Nota Yemetio, Emmanuel Yamb i Ndigui Billong. "Comparative study of the effects of a natural pozzolan and an artificial pozzolan on the hydraulic properties of Portland cement mortar". Global Journal of Engineering and Technology Advances 14, nr 1 (30.01.2023): 107–19. http://dx.doi.org/10.30574/gjeta.2023.14.1.0021.

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The comparative study of some effects of natural and artificial pozzolans on the hydraulic properties of Portland cement mortar is performed in this work. The natural pozzolan used coming from the Djoungo deposit, Moungo department in the Littoral region (Cameroon) was finely ground and then sieved at 100 μm. The artificial pozzolan used is the alluvial clay of Etoa collected from Yaoundé III District in Mfoundi Division of the Centre Region of Cameroon. It was thermally activated at 700°C after grinding and sieving. The chemical and mineralogical analysis of the raw materials were studied by X-ray fluorescence, infrared spectrometry (FTIR) and X-ray diffraction (XRD) then the specific surfaces and the absolute densities were determined. The formulation of the pastes and mortar was obtained by substituting Portland cement with different pozzolans at different percentages, while the initial and final setting time of the fresh pastes were determined. Linear shrinkage, water absorption, apparent density, flexural strength and compressive strength tests at 7 and 28 days were determined on the hardened mortars. The results obtained show an increasing in the initial and final setting time with the addition of the amount of pozzolan (natural or artificial), the pozzolans played the role of setting retarder in the mixtures, finer particles of the artificial pozzolan speed up the setting time of pastes as compared to that with natural pozzolan. The shrinkage of the hardened mortars increased with the addition of the pozzolans, but it was less than 0.2% in all the samples, the specimens with artificial pozzolans were more affected by the drying shrinkage. The mortars had good mechanical resistance but from 30 to 40% pozzolan, whether artificial or natural, the resistance dropped, the dilution phenomenon caused by the partial replacement of the cement was responsible for the drop in resistance with the addition of pozzolans. The water absorption rate and the apparent density of the specimens decrease when the percentage of pozzolan increases in the mortars. Artificial pozzolan offers a better water absorption rate compared to natural pozzolan due to its higher specific surface. Natural pozzolan makes it possible to obtain a denser mortar.

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Cabrera, Santiago, Kerstin Elert, Anabela Guilarducci i Andrea Margasin. "The effect of local pozzolans and lime additions on the mineralogical, physical and mechanical properties of compressed earth blocks in Argentina". Revista de la construcción 21, nr 2 (2022): 248–63. http://dx.doi.org/10.7764/rdlc.21.2.248.

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The purpose of this research is to evaluate the mineralogical, physical, and mechanical properties of compressed earth blocks (CEB) stabilized with lime and mineral admixtures easily obtained in Argentina: natural pozzolans and brick powder. the admixture mineralogical composition and their pozzolanic potential as well as the development of hydraulic phases upon reaction with calcium hydroxide (lime) were determined, emphasizing the formation of hydrated cementing compounds. Samples with different percentages of lime and mineral additions were prepared in order to test their compressive strength, wet erosion resistance, and water absorption, and contrasting the results with those of their counterparts stabilized exclusively with lime or cement. The results obtained allow us to affirm that both the brick powder and the pozzolan used have pozzolanic properties and, in combination with calcium hydroxide, form amorphous phases of C-(A)-S-H. However, the use of small amounts of both additions in combination with hydrated air lime in the manufacture of CEB, compared to CEB samples stabilized only with hydrated air lime, adversely affected their physical and mechanical properties.

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Taku, K. J., i Y. D. Amartey. "Suitability study of soybeans husk ash as a mixing material to OPC: Effect of calcination time-preliminary investigation". Kathmandu University Journal of Science, Engineering and Technology 12, nr 1 (12.11.2018): 13–22. http://dx.doi.org/10.3126/kuset.v12i1.21561.

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Soybeans husk was collected from a dump site, dried de-carbonated, separated into six samples and calcined at a temperature of 600 °C, for 1, 2, 3, 4, 5 and 6 hours respectively. Samples were taken for X- ray Florescence (XRF) analysis, Standard Electron Microscopy (SEM) imaging, setting time, standard water of consistency determination and specific gravity test. The result of XRF analysis revealed that the SHA contain less than 70 % SiO2+Al2O3+Fe2O3 stipulated by ASTM C618 for pozzolanas, but has very high CaO content. The SiO2 +Al2O3+Fe2O3 and CaO content though varies slightly with the calcination time of soybean husk. The specific gravity of SHA varies with calcination time of SH and ranges between 2.3 and 2.7 and is less than that of OPC irrespective of the calcination time. Setting times of OPC/SHA pastes at 10 % replacement of OPC with SHA increases with calcination time and is greater than that for OPC paste. The SEM analysis shows that the crystal structure of the SHA changes with calcination temperature. The compressive strength of mortar using OPC/SHA as a binder was determined after 7, 14 and 28 days curing and was found to be less than that for OPC mortars at all ages. However, the percentage reduction in strength decreased with curing age, with SHA calcined at 4 hours having the greater strength (i.e. 87.4 % of OPC strength at 28 days). The percentage gain in strength was more pronounced from 7 to 14 days. In all, SH calcined at 600 °C for 4 hours optimizes the pozzolanic potential of SHA.Kathmandu University Journal of Science, Engineering and Technology Vol. 12, No. I, June, 2016, Page: 13-22

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Malathy, Ramalingam, Ragav Shanmugam, Ill-Min Chung, Seung-Hyun Kim i Mayakrishnan Prabakaran. "Mechanical and Microstructural Properties of Composite Mortars with Lime, Silica Fume and Rice Husk Ash". Processes 10, nr 7 (21.07.2022): 1424. http://dx.doi.org/10.3390/pr10071424.

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A mixture of hydraulic lime and pozzolanic material can be used as a binder in making concrete and mortar for energy-efficient construction purposes. Generally, lime possesses lower strength and higher setting time. By introducing pozzolans in the lime mortar, their cementitious properties could be increased and could compete with the cement mortars. The use of pozzolan-lime binder in mortar reduces the utilisation of cement, and hence reduces the environmental problem originating from cement production. This study mainly deals with the mechanical and microstructural properties of lime and lime composite mortars made up of hydraulic lime, silica fume and rice husk ash. Three composite mortars were made with the following combination such as hydraulic lime-silica fume (LSF), hydraulic lime-rice husk ash (LRA) and hydraulic lime-silica fume-rice husk ash (LSR). Further, their properties were compared with the pure lime mortar. Preliminary investigations were made on the lime reactivity and pozzolanic reactivity tests. It was understood that silica fumes have a (15%) better reactivity than rice husk ash. The introduction of pozzolans in the lime mortar promotes fresh, hardened and microstructural properties. The 28 days’ compressive strength of lime composite mortars achieved more than 16 Mpa, while the lime mortar attained 4 Mpa. The combined effect of pozzolanic reaction, hydration and carbonation in the lime composite mortars achieved four times the strength of lime mortar at 28 days. A high peak of calcium carbonate was detected in lime mortar as a result of carbonation. The well-developed microstructure of calcium silicate hydrate and calcium hydroxide exhibits the formation of hydration products in the lime composite mortars as observed from a scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). Similar graphs of Fourier transform infrared spectroscopy (FT-IR) showed the presence of equivalent functional elements in all lime composite mortars.

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Jamellodin, Zalipah, Mohd Saman Hamidah, Suraya Hani Adnan, Noor Shuhada Mohammad i Wan Yuslinda Wan Yusof. "Strength Development of Fine Grained Mortar Containing Fly Ash and Rice Husk Ash". Applied Mechanics and Materials 752-753 (kwiecień 2015): 182–88. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.182.

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Fine grained mortar (FGM) offers a new innovative technology binder system. The innovative technique is achieved by using a small maximum grain size of 600μm for the mortars. Most of the previous studies have focused on the FA to be replaced in the FGM. There is still lacking of research of using other pozzolanas in making FGM. This paper presents a study of the strength of FGM with partially replacement of ordinary Portland cement (OPC) with fine fly ash (FA) and ground rice husk ash (RHA). Flexural and compressive strength of FGM were tested. The results show that the use of FA and RHA produces FGM with improved strength with the replacement up to 20% than that of the control FGM. The use of FA and RHA is very effective in enhancing strength at the later age of FGM.

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Pontes, Jorge, António Santos Silva i Paulina Faria. "Evaluation of Pozzolanic Reactivity of Artificial Pozzolans". Materials Science Forum 730-732 (listopad 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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Shakiba, Mohammad, Peyman Rahgozar, Amir Reza Elahi i Reza Rahgozar. "Effect of Activated Pozzolan with Ca(OH) 2 and nano-SiO2 on Microstructure and Hydration of High-Volume Natural Pozzolan Paste". Civil Engineering Journal 4, nr 10 (30.10.2018): 2437. http://dx.doi.org/10.28991/cej-03091171.

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The main aim of this study is to investigate the effect of activated pozzolan on hydration and microstructure of high-volume natural pozzolan paste. Thermal activation of natural pozzolan with Ca(OH)2 has been applied with nano-silica (NS) as activator at three different temperatures. X-ray diffraction (XRD), thermogravimetric analysis (TGA), laser particle analysis, scanning electron microscopy (SEM) with energy dispersive spectroscopy were employed. In order to analyze the test results, notions of “pre C-S-H” based on XRD and TGA results of activated pozzolan powders has been used. SEM images indicated microstructural improvements of the pastes with activated pozzolans compared to paste with natural pozzolan and natural pozzolan incorporating NS, showing the pore-filling effect of activated pozzolans. The microstructural improvements were proportion to the amount of pre C-S-H formed during the activation of pozzolan.

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Pavlíková, Milena, Pavla Rovnaníková, Martina Záleská i Zbyšek Pavlík. "Diatomaceous Earth—Lightweight Pozzolanic Admixtures for Repair Mortars—Complex Chemical and Physical Assessment". Materials 15, nr 19 (3.10.2022): 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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Saiteja Chary, K., S. Shrihari, V. Siva Prasad Raju i V. Srinivasa Reddy. "Influence of calcium and alumina-based pozzolanas on the strength properties of low calcium fly ash geopolymer concrete". E3S Web of Conferences 309 (2021): 01104. http://dx.doi.org/10.1051/e3sconf/202130901104.

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This work presents the effect of Ground granulated blast furnace slag (GGBS), fly ash (FA) and metakaolin (MK) on the strength properties of geopolymer concrete (GPC). Geopolymer concrete made with FA produces calcium aluminosilicate hydrate (C-A-S-H) product due to presence of alumina and sodium aluminosilicate hydrate (N-A-S-H) gel as main reaction product of polymerization. Geopolymer concrete made with FA and GGBS, calcium silicate hydrate (C-S-H) also gets produced additionally with calcium aluminosilicate hydrate (C-A-S-H) gel and sodium aluminosilicate hydrate (N-A-S-H) gel due to presence of high content of CaO in GGBS. This additional product imparts more strength performance in GPC. In geopolymer concrete made with FA and MK, the more amount of calcium aluminosilicate hydrate (C-A-S-H) is produced due to presence of high amount of alumina in metakaolin along with sodium aluminosilicate hydrates (N-A-S-H) giving more strength to GPC. Metakaolin is recommended to be used for the development of GPC because it has high amount of alumina.

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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, nr 1A (4.05.2018): 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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Arum, R. C., C. Arum i S. A. Alabi. "The highs and lows of incorporating pozzolans into concrete and mortar: A review on strength and durability". Nigerian Journal of Technology 41, nr 2 (2.06.2022): 197–211. http://dx.doi.org/10.4314/njt.v41i2.1.

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It has been established that the construction industry, especially with regards to the production and use of cement generates lots of toxic gases, as well as consumes large quantities of natural resources. Cement itself is an expensive constituent of concrete. In order to reduce environmental pollution, improve cost-savings in production, achieve carbon neutrality and sustainability, the focus should be directed at using alternative waste materials such as ceramic waste, waste glass, palm oil waste, and rice husk, among others. This paper presents a widescale review of the incorporation of pozzolans into concrete and mortar, highlighting the effects on its strength and durability. The review revealed that while the existing literature agrees that the incorporation of pozzolans into mortar and concrete generally improves their durability, there is an apparent contradiction in various research findings on the effect of pozzolans on their strength. The review has shown however that whether the inclusion of pozzolan will increase or decrease strength depends on a number of factors such as Portland cement replacement level, fineness of the pozzolan (particle size of the ash), the reactivity of the pozzolan, concrete/mortar age, type of pozzolan, water-cement ratio, burning temperature, the microstructure of the pozzolan (weakly or strongly amorphous).

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Khan, M. I., i A. M. Alhozaimy. "Properties of natural pozzolan and its potential utilization in environmental friendly concrete". Canadian Journal of Civil Engineering 38, nr 1 (styczeń 2011): 71–78. http://dx.doi.org/10.1139/l10-112.

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In Saudi Arabia, locally available natural pozzolanic material has the potential for use in environmental friendly concrete as a partial cement replacement. Local natural pozzolan was incorporated in concrete as a partial cement replacement to study the effect of replacement level, natural pozzolan fineness and its source. Chemical and physical properties of local natural pozzolan, properties of fresh concrete, compressive strength development, chloride permeability, and porosity of concrete incorporating local natural pozzolanic material as a partial cement replacement is presented. The influence of curing on the properties of concrete containing natural pozzolan and the X-ray diffraction analysis are reported. It was observed that regardless of its different sources, chemical and physical properties of local natural pozzolan are similar and conforms to the requirements of ASTM C 618, Class N. Concrete containing up to 15% natural pozzolan matches with the mix containing 20% fly ash, which is very close to the plain concrete. Higher dosages of this natural pozzolan can be utilized for economical and environmental benefits. This research is the first of its kind that addresses the investigation on Saudi natural pozzolanic material.

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Waghmare, Jagruti Dattatraya, Samruddhi Sampatrao Patil, Sheha Mahadeo Patil i M. Maske. "Study and Review of Properties and Applications of Portland Pozzolana Cement". ASEAN Journal of Science and Engineering 1, nr 1 (23.08.2021): 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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Li, Shiqyn, Della M. Roy i Amitabha Kumar. "Quantatative determination of pozzolanas in hydrated systems of cement or Ca(OH)2 with fly ash or silica fume". Cement and Concrete Research 15, nr 6 (listopad 1985): 1079–86. http://dx.doi.org/10.1016/0008-8846(85)90100-0.

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Stamatakis, M. G., D. Fragoulis, S. Antonopoulou i G. Stamatakis. "The opaline silica-rich sedimentary rocks of Milos Island, Greece and their behaviour as pozzolanas in the manufacture of cement". Advances in Cement Research 22, nr 3 (lipiec 2010): 171–83. http://dx.doi.org/10.1680/adcr.2010.22.3.171.

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Polozhiy, Kirill, Jamal Akhter Siddique i Pavel Reiterman. "Low Cost Cement Floor Screed". Materials Science Forum 824 (lipiec 2015): 77–80. http://dx.doi.org/10.4028/www.scientific.net/msf.824.77.

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Floor screed with different amount of pozzolanic admixture was studied. There were designed 3 mixtures with different amount of the pozzolana. The basic physical properties, mechanical properties and frost resistance were determined. The water /cement coefficient was decided to be taken according to the consistence of the mortar. The mixtures were designed with respect to their application as screed. The properties of developed low-cost pozzolanic screed exceeds the reference material.

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Prathap, M. G., J. S. Sudarsan i S. Nithiyanantham. "Performance on Self-Compacting Concrete Using Ground Granulated Blast-Furnace Slag (GGBFS)". Advanced Science, Engineering and Medicine 12, nr 12 (1.12.2020): 1509–12. http://dx.doi.org/10.1166/asem.2020.2713.

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Concrete is likely the most widely utilized development material on the planet with around six billion tones being created each year. It is just close to water as far according to capita utilization. It makes more impacts condition perspectives and causes more harm because of crude material extraction and outflow of carbon dioxide during the creation of concrete. The ecological issues had made analysts around the globe to lessen the use of concrete utilization by replacing the concrete by including different materials, which are happening normally, squander items from businesses which utilizes less vitality. These materials are called as pozzolanas which can be which can joined with calcium hydroxide, displays cementitious properties. Most ordinarily admixtures utilized in the concrete substance are Conplast 430. This admixture is to be analysed for its presentation when it is blended in with concrete so that can give decrease in life cycle cost. The main objective of this study is to focus the characteristics of M20 and M40 grade concrete with replacing partially of cement with 10%, 20% and 30% of Ground Granulated Blast Furnace Slag (GGBFS) by using the cubes, cylinders which were examined as compressive, split tensile and flexural strengths.

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Kelly, Fergal. "A review of GGBS use in the UK and its role in reducing embodied carbon". Structural Engineer 101, nr 07 (3.07.2023): 24–27. http://dx.doi.org/10.56330/rgta3245.

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The current approach to the carbon assessment of concrete uses a system boundary limited to a given project. Where cement replacements such as ground granulated blast-furnace slag (GGBS) are used to reduce carbon, the benefit to the project relies on the assumption that GGBS was a waste product. However, estimation of the historical production and use of GGBS in the UK shows that it has been used in concrete to its maximal extent for two decades or more, mainly due to its low cost and beneficial effects on the physical properties of concrete. Therefore, while specifying GGBS on individual projects gives a carbon saving within the project boundary, it does not reduce emissions at a national level. Given the importance of GGBS from a technical perspective, it is proposed that its use should be focused on these technical benefits, rather than as a low-carbon cement replacement. This, along with likely future supply issues, illustrates the urgency of moving past our dependency on GGBS and focusing on alternatives such as calcined clays, pozzolanas and limestone fines to reduce the carbon intensity of concrete.

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Martín, Domingo A., Jorge L. Costafreda, Leticia Presa, José Zambrano i 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, nr 1 (25.01.2022): 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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Záleská, Martina, Milena Pavlíková i Zbyšek Pavlík. "Classification of a-SiO₂ Rich Materials". Materials Science Forum 824 (lipiec 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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Costafreda, Jorge Luis, i Domingo Alfonso Martín. "New Deposit of Mordenite–Clinoptilolite in the Eastern Region of Cuba: Uses as Pozzolans". Molecules 26, nr 15 (2.08.2021): 4676. http://dx.doi.org/10.3390/molecules26154676.

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This work describes the newly discovered zeolites in the eastern region of Cuba. In the researched area, there have been no previous studies of natural zeolite exploration. Therefore, the results shown here are new. The main object of this research is to analyse five samples of zeolites and demonstrate their pozzolanic capacity and the possibility of their usage in the industrial manufacturing of pozzolanic cements. The study of the samples was performed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). A chemical analysis (CAQ) to determine the quality of the samples as pozzolans was performed, by determining the total SiO2, reactive SiO2, total CaO, reactive CaO, Al2O3, MgO and the insoluble residue (I.R.). Lastly, an eight-day pozzolanicity analysis (PA) was carried out to determine the pozzolanic reactivity of the samples. The results obtained by XRD, XRF and SEM established that the researched zeolite samples have two main zeolitic phases: mordenite and clinoptilolite. Altered volcanic glass, quartz and smectite (montmorillonite) are the secondary phases. The results of the chemical quality analysis (CAQ) showed that the samples contain a considerable amount of reactive SiO2 and reactive CaO, as well as a low content of insoluble residue, which reinforces their properties as pozzolans. The results of the pozzolanicity analysis (PA) concluded that the analysed samples actively react with Ca(OH)2 after eight days. Based on all the results mentioned above, it is established that both mordenite and clinoptilolite behave like pozzolans and can be recommended for the manufacture of pozzolanic cements, which have more effective properties than Portland cement, in terms of physical, chemical and mechanical strength, low heat of hydration, resistance to sulphates, low CO2 emissions to the atmosphere and negligible impacts on the environment.

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Małolepszy, Jan, i Ewelina Grabowska. "The influence of zeolites on hydration process of mineral binders". Budownictwo i Architektura 12, nr 3 (11.09.2013): 185–92. http://dx.doi.org/10.35784/bud-arch.2031.

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This paper presents the results of physical and chemical properties of zeolite - clinoptilolite (Z), on the basis of which its usefulness in different terms and applications was assessed. Same pozzolan was also investigated and analyzed in term of the changes that it causes in the system pozzolan - cement – lime - sand - water with different content of ingredients. In order to identify the hydration products in the natural conditions, infusion (80ºC) and autoclaving (180°C) XRD, DTA / TG and SEM was used. The results indicate that clinoptilolite is characterized by moderate pozzolanic activity and can be successfully used as a pozzolanic additive for cement, and a binder in the production of aerated concrete.

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Pourkhorshidi, A. R., J. Sobhani i A. A. Ramezanianpour. "A geochemical assessment method for identification of natural pozzolans as supplementary cementitious material". Advances in Cement Research 33, nr 12 (grudzień 2021): 550–60. http://dx.doi.org/10.1680/jadcr.21.00078.

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Pozzolans are available in natural resources as raw materials that are potentially applicable in the cement and concrete industries. Proper identification and exploration methods are crucial in relation to their technical and economical purposes. In this paper, a two-phase study is employed, based on geochemical data processing and experimental investigations. Chemical and petrography of natural pozzolans were utilised to develop the proposed method. This method proposes three geochemical indexes: the limiting values of silica/calcium oxide (SiO2/CaO), alumina saturation and alkali content to qualify the natural pozzolan according to the supplementary cementitious requirements. Then, based on ASTM C618 and EN 196-5 standards and complementary tests, the chemical and physical properties of two natural pozzolans were assessed to validate the proposed method. The results showed that this method could be used as a robust and direct way to identify natural pozzolans.

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