scholarly journals Effects of Red Mud Addition in the Microstructure, Durability and Mechanical Performance of Cement Mortars

2019 ◽  
Vol 9 (5) ◽  
pp. 984 ◽  
Author(s):  
José Ortega ◽  
Marta Cabeza ◽  
Antonio Tenza-Abril ◽  
Teresa Real-Herraiz ◽  
Miguel Climent ◽  
...  
Keyword(s):  
Portland Cement ◽  
Red Mud ◽  
Mechanical Performance ◽  
Network Evolution ◽  
Cement Industry ◽  
Pozzolanic Activity ◽  
Great Effort ◽  
Chloride Ingress ◽  
Cement Mortars ◽  
Cement Based Materials

Recently, there has been a great effort to incorporate industrial waste into cement-based materials to reach a more sustainable cement industry. In this regard, the Bayer process of obtaining alumina from bauxite generates huge amounts of waste called red mud. Few research articles have pointed out the possibility that red mud has pozzolanic activity. In view of that, the objective of this research is to analyse the short-term effects in the pore structure, mechanical performance and durability of mortars which incorporate up to 20% of red mud as a clinker replacement. As a reference, ordinary Portland cement and fly ash Portland cement mortars were also studied. The microstructure was characterised through mercury intrusion porosimetry and non-destructive impedance spectroscopy, which has not previously been used for studying the pore network evolution of red mud cement-based materials. The possible pozzolanic activity of red mud has been checked using differential scanning calorimetry. The non-steady state chloride migration coefficient and the mechanical properties were studied too. According to the results obtained, the addition of red mud entailed a greater microstructure refinement of the mortar, did not worsen the resistance against chloride ingress and reduced the compressive strength compared to control binders.

Physical and Chemical Influence of Polyacrylate Latex on Cement Mortars

2011 ◽  
Vol 261-263 ◽  
pp. 807-811 ◽  
Author(s):  
Ye Tian ◽  
Zong Jin Li ◽  
Hong Yan Ma ◽  
Xian Yu Jin ◽  
Nan Guo Jin
Keyword(s):  
Pore Structure ◽  
Cement Hydration ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Air Entrainment ◽  
Hydration Products ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Physical And Chemical ◽  
Chemical Influence

In this research, the physical and chemical influence of polyacrylate (PA) latex on cement-based materials were studied using polymer modified mortars with polymer/cement (P/C) ratios of 0%, 5% and 10%. Physically, the mechanical performance of PA latex modified mortars was investigated with compression toughness energy and bending strength. Further more, a comparison of the pore structure and porosity between PA latex modified and unmodified mortars was conducted. The chemical reactions between PA polymer and cement hydrates were clarified with thermogravimetric (TG) analysis. It can be concluded from this research that PA polymer can refine the pore structure of cement mortars and link the cement hydration products together chemically. While, at the same time, PA latex addition can cause air entrainment which will weaken the physical behavior of cement mortars. So there is an optimum P/C ratio to achieve the best mechanical properties. And in this research, the optimum P/C ratio is 5%.

scholarly journals Utilization of Iron Ore Tailings as Raw Material for Portland Cement Clinker Production

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Li Luo ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Tiejun Chen
Keyword(s):  
Portland Cement ◽  
Iron Ore ◽  
Mechanical Performance ◽  
Mineralogical Composition ◽  
Cement Industry ◽  
Raw Material ◽  
Cement Clinker ◽  
Iron Ore Tailings ◽  
Portland Cement Clinker ◽  
Clinker Production

The cement industry has for some time been seeking alternative raw material for the Portland cement clinker production. The aim of this research was to investigate the possibility of utilizing iron ore tailings (IOT) to replace clay as alumina-silicate raw material for the production of Portland cement clinker. For this purpose, two kinds of clinkers were prepared: one was prepared by IOT; the other was prepared by clay as a reference. The reactivity and burnability of raw meal, mineralogical composition and physical properties of clinker, and hydration characteristic of cement were studied by burnability analysis, differential thermal analysis, X-ray diffraction, and hydration analysis. The results showed that the raw meal containing IOT had higher reactivity and burnability than the raw meal containing clay, and the use of IOT did not affect the formation of characteristic mineralogical phases of Portland cement clinker. Furthermore, the physical and mechanical performance of two cement clinkers were similar. In addition, the use of IOT was found to improve the grindability of clinker and lower the hydration heat of Portland cement. These findings suggest that IOT can replace the clay as alumina-silicate raw material for the preparation of Portland cement clinker.

Effect of hydrated lime on efflorescence formation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Diogo Henrique de Bem ◽  
Priscila Ongaratto Trentin ◽  
Ronaldo A. Medeiros-Junior
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Design Methodology ◽  
Hydrated Lime ◽  
Content Type ◽  
Mercury Intrusion ◽  
Lime Content ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Historical Heritage

PurposeEfflorescence formation is very common in cement-based materials. In the case of mortar, efflorescence is more studied when only Portland cement is used as a binder. However, the repair of historical heritage, as well as the construction system of some countries, usually uses mortars composed of hydrated lime and Portland cement. This study aims to determine the influence of the hydrated lime content on the incidence of efflorescence in mortars.Design/methodology/approachMortars with 0%, 50%, and 100% lime/cement ratio were studied, using three different methods to accelerate efflorescence formation. The surface area of mortars affected by efflorescence was quantified by analysis using image software. Also, analysis of mercury intrusion porosity test, flexural tensile, compressive strength, absorption of water by capillarity, porosity, XRD and TGA was performed.FindingsMore efflorescence in mortars with a higher amount of lime in their composition was observed. The results show that the increase in the lime content reduces the flexural tensile and the compressive strength and increased the absorption of water by capillarity and the porosity of the mortars. The material formed by the efflorescence was calcium carbonate, proven by microstructural tests.Originality/valueThe results of greater efflorescence formation in mortars with lime are important to alert users who apply this type of material. Some type of protection must be done more rigorously for lime-cement mortars, especially concerning contact with water, since efflorescence tends to be faster for this type of material.

scholarly journals Reduced Carbonation, Sulfate and Chloride Ingress Due to the Substitution of Cement by 10% Non-Precalcined Bentonite

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1300
Author(s):  
Carmen Andrade ◽  
Ana Martínez-Serrano ◽  
Miguel Ángel Sanjuán ◽  
José Antonio Tenorio Ríos
Keyword(s):  
Portland Cement ◽  
Cement Industry ◽  
Chloride Ingress ◽  
Gas Emissions ◽  
Nineteen Seventies ◽  
Novel Approach ◽  
Carbonation Resistance ◽  
Structural Applications ◽  
Mineral Additions ◽  
Clinker Production

The Portland cement industry is presently deemed to account for around 7.4% of the carbon dioxide emitted annually worldwide. Clinker production is being reduced worldwide in response to the need to drastically lower greenhouse gas emissions. The trend began in the nineteen seventies with the advent of mineral additions to replace clinker. Blast furnace slag and fly ash, industrial by-products that were being stockpiled in waste heaps at the time, have not commonly been included in cements. Supply of these additions is no longer guaranteed, however, due to restrained activity in the source industries for the same reasons as in clinker production. The search is consequently on for other additions that may lower pollutant gas emissions without altering cement performance. In this study, bentonite, a very common clay, was used as such an addition directly, with no need for precalcination, a still novel approach that has been scantly explored to date for reinforced structural concrete with structural applications. The results of the mechanical strength and chemical resistance (to sulfates, carbonation and chlorides) tests conducted are promising. The carbonation findings proved to be of particular interest, for that is the area where cement with mineral additions tends to be least effective. In the bentonite-bearing material analysed here, however, carbonation resistance was found to be as low as or lower than that observed in plain Portland cement.

scholarly journals Eco-Efficient Hybrid Cements: Pozzolanic, Mechanical and Abrasion Properties

2020 ◽  
Vol 10 (24) ◽  
pp. 8986
Author(s):  
Segundo Shagñay ◽  
Leticia Ramón ◽  
María Fernández-Álvarez ◽  
Asunción Bautista ◽  
Francisco Velasco ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Industry ◽  
Pozzolanic Activity ◽  
Partial Replacement ◽  
Mechanical Resistance ◽  
Abrasion Test ◽  
Cement Ratio ◽  
Activated Slag ◽  
Substitute Materials

One of the most polluting industries is the cement industry and, for this reason, alternative lines of research recommend the use of substitute materials for traditional Portland cement. This study proposes the use of industrial (slag and fly ash) and ceramic wastes for the total or partial replacement of Portland cement in the manufacturing of both alkaline-activated and hybrid cements. To carry out this study and evaluate the behavior of the proposed materials, different mortars were manufactured: Portland cement (CEM I), two alkaline-activated slag systems and six hybrid systems, with an 80–20% waste-to-Portland-cement ratio for all the proposed wastes. An assessment of the pozzolanic activity was carried out for the different materials. The behavior of all the systems regarding mechanical resistance and durability to abrasion was studied. All the proposed materials, especially those with ceramic wastes, showed pozzolanic activity and suitable characteristics for use in the manufacturing of alternative cements. The mortar made of slag activated with waterglass presented the highest mechanical strength and lowest porosity, but the hybrid materials presented competitive results. After being subjected to the Böhme abrasion test, their effectiveness as substitutes for Portland cement is reiterated, some of them improving their durability to wear.

Properties of Cement-Based Materials Containing Melting Incinerator Bottom Ash

2011 ◽  
Vol 250-253 ◽  
pp. 834-838 ◽  
Author(s):  
An Cheng ◽  
Hui Mi Hsu ◽  
Sao Jeng Chao ◽  
Wei Ting Lin ◽  
Hao Hsien Chen ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Particle Size ◽  
Compressive Strength ◽  
Portland Cement ◽  
Bottom Ash ◽  
Pozzolanic Activity ◽  
Unit Weight ◽  
Maximum Particle Size ◽  
Cement Based Materials ◽  
Maximum Particle

This paper presents an experimental investigation on the effect of incinerator bottom ash (IBA) fineness and the cooled process of molten IBA on fresh mortar properties and compressive strength of hardened mortars. IBA with two finenesses, an original IBA, and a pulverizing incinerator bottom ash (PIBA) powder, with maximum particle size of 4.75 and 0.074 mm respectively were used to partially replace sand and Portland cement at 0%, 10%, 20%, 30%, and 40% by weight. The pozzolanic activity characteristics of powder were obtained from melting the above PIBA in an electric-furnace at 1450 °C for 1 h. and chilled by quenching in water (WIBA) and air (AIBA). Results indicate that incinerator bottom ash caused a reduction in compressive strength, unit weight, and flowability values when used as a replacement for sand and cement. However, IBA can be processed by melting to regain reactive pozzolanic activity, which may be used to partially replace cement.

scholarly journals The Use of Volcanic Powder as a Cement Replacement for the Development of Sustainable Mortars

2020 ◽  
Vol 10 (4) ◽  
pp. 1460
Author(s):  
Viviana Letelier ◽  
José Marcos Ortega ◽  
Rosa María Tremiño ◽  
Bastián I. Henriquéz-Jara ◽  
Ivo Fustos ◽  
...  
Keyword(s):  
Portland Cement ◽  
Greenhouse Gases ◽  
Pore Structure ◽  
Co2 Emissions ◽  
Environmental Effects ◽  
Ordinary Portland Cement ◽  
Mechanical Performance ◽  
Cement Industry ◽  
Environmental Benefits ◽  
Greenhouse Gases Emissions

Currently, reduction of environmental effects of the cement industry is an issue of global interest and one of the alternatives is to replace clinker with additions such as volcanic powder. The purpose of this work is to study the influence of up to 400 hardening days of volcanic powder, obtained from the last eruption of the Calbuco volcano (Chile), on the pore structure, mechanical performance, and durability-related properties of mortars which incorporate up to 20% volcanic powder as a substitution for clinker. In addition, an evaluation of greenhouse gases emissions was performed in order to quantify the possible environmental benefits of incorporating the volcanic powder in the mortars. The results obtained indicated that mortars with contents of 10% and 20% of volcanic powder had adequate service properties and improved all durability-related properties overall as compared with those noted for ordinary Portland cement. Additionally, the use of up to 20% volcanic powder makes it possible to reduce the CO2 emissions of mortars by almost 20%, demonstrating the advantages of incorporating this addition in mortars.

Rheological properties and hydration behavior of portland cement mortars containing calcined red mud

2013 ◽  
Vol 40 (6) ◽  
pp. 557-566 ◽  
Author(s):  
D.V. Ribeiro ◽  
A.S. Silva ◽  
J.A. Labrincha ◽  
M.R. Morelli
Keyword(s):  
Portland Cement ◽  
Rheological Properties ◽  
Red Mud ◽  
Cement Mortars

The Portland Cement Industry of the World

1898 ◽  
Vol 46 (1192supp) ◽  
pp. 19108-19109
Author(s):  
Bernard L. Green
Keyword(s):  
Portland Cement ◽  
Cement Industry ◽  
The World
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